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Senior Design Project:
Smart Consumer Home Network Appliance Power System
EEL 4914
Senior Design 1
Group Members:
Maeve Casey
Nicholas Mulqueen
Shawn McDorman
Sponsored By:
Duke Energy
December 2, 2013
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Table of Contents and Figures 1.0 Executive Summary .................................................................................................. 1
Figure 2.1 Washington Post graph showing cost of annual blackouts increasing and consumers are paying for it.. ................................................................................... 2
2.2 Goals and Objectives ............................................................................................ 4
2.3 Project Requirements and Specifications .............................................................. 5
2.3.1Deliverables ..................................................................................................... 5
Figure 2.3.1 Block Diagram of Deliverables Communication ................................... 6
2.3.2 Technologies Used ......................................................................................... 6
3.0 Research Related to Project Definition ..................................................................... 7
Figure 3.1.1 Graphs displaying the correlation between electrical equipment demand and the amount of disposable income consumers have. ............................ 8
3.2 Similar Products .................................................................................................... 9
Figure 3.2 - Typical configuration for a home area network supporting energy measurements using current transformers. ............................................................10
3.3 Whole House Monitor : Pulse Sensor ...................................................................11
Figure 3.3 – Power Cost Monitor pulse sensor clamp shown on electricity meter with accompanying IHD. ................................................................................................12
3.4 Circuit by Circuit Measuring: The Current Transformer .......................................12
Figure 3.4 Shows an current transformer monitoring system that attaches and measure every individual circuit in the house..........................................................12
3.5 Individual Appliance Measuring: The Analog Front End .......................................13
Figure 3.5 The classic AFE, the Kill A Watt® from P3 International ........................14
4.0 Hardware and Software Design Research ...............................................................15
4.1 Brief Overview of Subsystems .............................................................................15
4.1.1 Main Device Hub ...........................................................................................16
Figure 4.1.1 Main Hub Block Diagram ....................................................................16
4.1.2 Wall Device ...................................................................................................17
Figure 4.1.2 Data Flow of Wall Unit ........................................................................17
4.1.3 Device Enabled Browser Based Software ......................................................18
4.1.4 Mobile App ....................................................................................................18
4.2 Wall Device ..........................................................................................................18
4.2.1 Power Monitoring Microcontroller...................................................................18
Table 4.2.1 Power Monitoring MCU Comparison ....................................................19
Figure 4.2.1 Example Block Diagram of MSP430AFE253 Application ....................20
Figure 4.2.1-1 Recommended Operating Conditions and Ratings for MSP430AFE253 .....................................................................................................21
Figure 4.2.1-3 Voltage versus Frequency for the MSP430AFE253 .........................23
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Figure4.2.1-4 Current characteristics For MSP430AFE253 in active mode ............22
4.2.2 Bluetooth Transceiver for Wall device ............................................................23
Table 4.2.2 Quick summary of Bluetooth Devices ..................................................23
Figure 4.2.2-1 Example Application Schematic .......................................................24
Figure 4.2.2-2 CC2541 Typical Electrical Characteristics ........ Error! Bookmark not defined.
Figure 4.2.2-3 Comparative Current Consumption Using TPS62730 in Low Energy Mode ......................................................................................................................25
4.2.3 Power Supply ................................................................................................26
Figure 4.3.2-1 Capacitive Power Supply for MSP430AFE253 ................................27
Figure 4.3.2-2 Switching based power supply to power additional components ......27
4.2.4 Antenna and Balun ........................................................................................29
Figure 4.2.4 Comparison of Reference Balun to Murata Balun ...............................29
4.2.5 Current Transformer ......................................................................................29
4.3 Main Hub .............................................................................................................30
4.3.1 T.I. Metrology ................................................................................................30
4.3.2 Electrical Standards Required by Utility Meters .............................................31
4.3.3 The Internet of Things ....................................................................................31
Figure 4.3.3 Basic elements that make up the smart home area network for measuring electricity consumption ..........................................................................33
4.3.4 Metering Devices that Apply to our Project ....................................................33
Figure 4.3.4 Block diagram of the master and slave processors, the MSP430F6638 and the MSP430AFE, respectively .........................................................................33
4.3.5 The Host Processor .......................................................................................34
Figure 4.3.5-1 Functional block diagram of the MSP430F6638 Error! Bookmark not defined.
Figure 4.3.5-2 Displays the 74 I/O pins on the MSP430F6638 ...............................34
4.3.6 Communication with the MSP430F6638 ........................................................35
Figure 4.3.6 – Block Diagram portraying communication between devices. ............36
4.3.7 Bluetooth Node ..............................................................................................36
4.3.8 SiteplayerTM ...................................................................................................37
Figure 4.3.8 Siteplayer Functional Block Diagram. .................................................37
5.0 Project Prototype Construction and Code ................................................................43
5. 1 Parts Acquisition and Bill of Materials .................................................................44
Table 5.1.1 BOM for CC2541 Part 1/2 ...................... Error! Bookmark not defined.
Table 5.1.1 BOM for CC2541 Part 2/2 ...................... Error! Bookmark not defined.
Table 5.1.2 BOM for MSP430F6638 ......................... Error! Bookmark not defined.
Table 5.1.3 BOM for MSP430AFE2XX ...................................................................47
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5.2 PCB and Assembly Information ...........................................................................47
Figure 5.2.1 MSP430F6638 Evaluation Schematic .................................................48
Figure 5.2.2 MSP430AFE253 Evaluation Schematic ..............................................49
Figure 5.2.3 CC2541 Evaluation Schematic ...........................................................50
Figure 5.2.4 SiteplayerTM Development Kit Schematic ............................................51
6.0 Project Prototype Testing ........................................................................................53
6.1 Hardware Methods of Testing ..............................................................................53
Figure 6.1.3 – These are typical power functions that the MSP430’s energy library must be able to calculate ........................................................................................58
Figure 6.1.4 MSP-TS430PW24 Target Socket Module, PCB .................................60
6.1.6 Bluetooth Testing and Evaluation ..................................................................61
Figure 6.1.6 Transmission Values for CC2541 Matched to a 50 Ohm Antenna ......61
Figure 6.1.6-1 Typical Receiving Characteristics For CC2541 ................................62
6.1.7 SiteplayerTM Testing and Evaluation ..............................................................62
Figure 6.1.7 Schematic of SiteplayerTM Application. ................................................63
6.2.3 SitePlayer Data Flow Chart............................................................................65
Figure 6.3.1 SitePlayer Editor ................................................................................69
7.1 Milestone Discussion ...........................................................................................74
Figure 7.1 Milestone Timeline .................................................................................74
7.2 Budget and Finance Discussion ...........................................................................75
Table 7.2 Estimated Budget ...................................................................75
Appendix A: Copyright Permissions ...............................................................................77
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1.0 Executive Summary
S.C.H.N.A.P.S (Smart Consumer Home Network Appliance Power Systems) is a project aimed at educating the public on energy awareness.
Demand for electricity continues to rise, while the electricity grid continues to get older. In order to keep America powered the electrical grid needs a serious remodeling, however this is a very expensive task. On the other hand, encouraging consumers to reduce their energy waste will make a huge difference on the amount of demand that the grid experiences.
Unfortunately, this has not been an easy task for utility companies. Electricity has become a novelty in our society and is treated as commonly as oxygen that is until the lights go out. Furthermore, electricity is cheap over small amounts of time, only costing a couple cents to charge a laptop for an hour. The short term savings of unplugging devices does not create enough incentive for consumers to change their energy consumption habits.
Our project intends to create the incentive for customers to take charge of their energy usage. This will be accomplished by through enabling household appliances and devices to communicate their energy consumption over the network and making this information available to the customer on the computer or other web enabled device.
One of our systems would consist of several wall plug-ins that could measure and calculate the power of an individual appliance or device and then send that information to a host microcontroller. The host microcontroller would act as a collection hub for the various plug – in device measurements and forward all this information to a server. Giving the consumer access to all the information of their power consumption by logging into the website online.
The idea behind this is to create awareness about energy efficiency and conservation in the consumer’s home. Blackouts and rolling brownouts due to high-energy demand can be easily prevented if consumers knew what load peak times were and what time they happened. Furthermore, making the customers aware of peak load times will prepare them for the future of the electrical grid. Electricity is a mysterious topic to many people because they have never taken the time to understand it and nobody has bothered to explain it to them. Our project aims to be the tool the general public uses to understand how easy it is to conserve energy, prevent blackouts from happening, and be good to the planet all while saving money!
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2.0 Project Descriptions
2.1 Project Motivations
Figure 2.1 Washington Post graph showing cost of annual blackouts increasing and consumers are paying for it. Reprinted with Permission
(Pending) from The Washington Post.
The U.S. electrical power grid has been named “The Greatest Engineering Achievement of the 20th Century” by the National Academy of Engineering (Engineering), despite the fact that in a world of constantly updating technology, this modern marvel has not changed much since Thomas Edison first supplied power to Manhattan over 130 years ago. Electricity has become so essential in our day to day lives that it is easy to take it for granted, until the moment we don’t have access to it. According to the Washington Post, “U.S. electric customers are now paying 43 percent more to build and maintain local power grids than they did back in 2002. “At the same time, the grid is also becoming less reliable, with blackouts now taking 20 percent longer to fix” (Plumer). The following figure shows a graph from the Washington Post article displaying the linear correlation between the amount of money customers have spent on repairing a weakening electricity grid.
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Currently, the only system that power companies have in place to react to and fix power outages relies solely on customers calling their power company's automated voice response services and reporting their issue. Furthermore, power companies are in the dark as to whether or not power has been restored to an individual house until that household calls the power company again to confirm that power has been restored. In the event of a storm or hurricane, millions of people are at risk to lose power, this causes a major, costly problem for utility companies; prioritizing and restoring power to their customers.
Obviously, the archaic grid that our country is being supplied by is in desperate need for some updates and expansion in order to accommodate energy demand - that is rising at 1 percent every year. However, this is a very costly endeavor, requiring an estimated cost of $673 billion to truly modernize according to a recent study by the American Society of Civil Engineers (Thompson). When in fact there is a simple solution, turning off lights and other electronics when they are not in use! According to IEEE, “residential energy consumption accounts for 21% of the total electricity use in the United States. Unfortunately, research indicates that almost 41% of this power is wasted” (Alahmad, Wheeler and Schwer). The first step towards reducing electrical load demand on the grid is by decreasing the amount of energy used by consumers. This requires a behavioral change on the consumer side of things.
Utility companies across the nation have been gearing up for the future electric grid by deploying smart meters that will be able to communicate more than just electricity usage. Millions of consumers around the country have already received their very own smart meter from their utility company, this meter will act as a messenger of power consumption data between the utility customer and consumer, however it will talk about more than just electricity consumption. According to the Innovation Electricity Efficiency Institute of the Thomas Edison Foundation, approximately 46 million smart meters have already been deployed in the US (Duke has installed nearly 50,000 smart meters in Florida alone), and they show no signs of stopping, with utility companies now focusing on integrating newer technologies into the grid (Innovation Electricity Efficiency).
Applications such as two way communication of electricity data will provide utility companies the ability to implement dynamic pricing to account for demand response time.
The consumer will see these changes in the subsequent bill they receive from the power company after the smart meter is installed, Dynamic Pricing is a feature of the smart grid that will set the cost of a kilowatt-hour based on the time of day – during peak demand times electricity will be more expensive and cheaper during off peak times. This concept is intended to offset the amount of power demanded during peak times in order to prevent electrical faults due to an overloaded system.
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Our project aims to educate consumers on their energy usage and provide them with the tools to curb their use. S.C.H.N.A.P.S is a home power monitoring system which allows consumers to have greater control over their power usage. POWERGRID International reports that, “studies show that consumers who track their daily energy consumption have cut it some 15%” (Miller and Littmann-Ashkenazi). Creating a platform where users can easily manage and track where they are wasting energy is the first step to reducing unnecessary consumption and decreasing the load on the grid. Additionally, the revolution in electricity measuring is coming to a meter near you. Soon everybody will have to adjust to the new method of billing that the utility companies will implement, our system intends to prepare the consumer for this change by giving them insight on what demand response time is, why it is an important time for reducing energy consumption and how much money it can save you to do so.
2.2 Goals and Objectives S.C.H.N.A.P.S is a project aimed at educating power consumers on controlling their energy consumption. We hope that integrating our technology into everyday life will provide consumers with the opportunity to become aware of their energy consumption. The only way this system will be marketable is if it is attractive to consumers in order to fulfill this requirement the system must:
Be easy to install – we want anybody to be able to enjoy the benefits of saving money on their electric bill, while also reducing demand on the grid
User-friendly interface – total control over energy consumption, by providing instructions at their fingertips
Provide an incentive for continued use – allow users to see long term savings by cutting back on waste
To accomplish this, our system will be made up of 3 main parts
Several Individual Analog Front End Appliances – which will be able to measure power of individual appliances or devices and perform power calculations
A main hub MCU – This is where information from all of the individual AFEs will be wirelessly sent and collected
A server – The final destination for the various measurements that have been collected throughout the household
Our system is not only intended to collect data but also to interpret the data it collects and present it to the customer. There are various measurements and calculations that can be extrapolated from the collected data, some more vital than others. Some of the values that we find are more relevant to encouraging power reduction include the ability to:
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Measure and log individual home appliance energy consumption, in order to allow tracking
Present how much per Kilowatt Hour a device is costing you
Display how much money you have saved by keeping an appliance turned off
Inform the consumer when phantom power is being drawn and encourage them to turn off the device
Allow remote control of individual AFE plugs
2.3 Project Requirements and Specifications
2.3.1 Deliverables
What we planned on creating here is a power monitoring device that displays the device data straight to mobile app devices. This feature allows consumers to read their power consumption on the fly and be aware of how much power they are consuming. Other metrics will also be displayed through the app such as but not limited to: how much power is used, history of power consumption, how money was saved month per month.
The main hub will be able to wirelessly connect with all units in the household, of which we plan to have anywhere from 2-8 units being able to attach to one hub. The wall units will be able to send power metrics wirelessly and will also be configured with an ability to be shutoff remotely through the app interface. This can be used to help cut off any power used through standby appliances and consumer electronics. The power used by these smaller units will be small as designs call for ultra-low power consuming devices on the interface.
Another thing we would like to deliver is the ability of the device to be integrated into a system that allows power companies to be contacted via the touch of a button. The app will have a feature that contacts the users power company via email with a pre loaded message alerting the company of an outage. This way the device and app can be used to help the power companies with grid management. Figure 2.3.1 is the idea of what the group would like to deliver in terms of overall of data.
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Figure 2.3.1 Block Diagram of Deliverables Communication
2.3.2 Technologies Used The device utilizes various technologies all geared toward making a more efficient power monitoring device. With our main concern being power management, a very efficient power monitoring IC is needed. Communication devices also needed to be low power consuming but still have a high rate of data transmission.
There are several companies that make power monitoring IC's and as such we reviewed several possible options to determine which will best accommodate our needs. Most of these IC's provide ultra low power to prevent a leeching of power from monitoring. These will be implemented into the wall units that go throughout the consumers’ house. As well these devices will be outfitted with wireless modules.
For our wireless communications we have chosen a solution that incorporates Bluetooth and Wi-Fi. There are other suitable methods of wireless communication but the reason we chose not use them will be addressed later in this report. The modules will be compatible with devices and be required to have two way communication to send data to and from the wall units and main hub. All modules will ideally be that geared to low power consumption in devices.
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The main unit uses a microcontroller that is clocked to send and receive data as well as communicate with the wall units. It will also be able host its own webpage data using a device called SitePlayerTM. SitePlayer allows custom web based data to be accessed via web browser. This can be used alongside the mobile app, though functionality may be limited to in home use. We will however try to incorporate a way to access the system through devices away from the home to allow the user to manage and control the drain from vampire power consumption. This will be achieved through a subsystem that will allow to shut of the device through remote access and putting wall device in a low power standby mode. This may seem redundant as other devices were in a standby mode, but we hoped to minimize the impact of vampire power to just the wall units which should consume far less power than many larger appliances in their standby modes.
3.0 Research Related to Project Definition
3.1 Industry Report
The industry that our project best fits under is defined as ‘Electronic Part & Equipment Wholesaling in the US (NAICS: 42369) (Harrison). This field is expected to create total revenue of $262.9Billion in 2013 for the various innovative technologies that it fabricates. Major products and services that come out of this industry include: circuit boards and parts, communication parts and equipment, electronic parts and testing equipment, semiconductors et cetera. The various devices that have been developed through the aggregate of these electronic parts and components have sparked a wireless revolution that is transforming the world around us.
Currently, communications equipment sector takes up the largest percentage of the market at 35.6% of the pie. A surge in consumer demand for instant access to data bits whenever, wherever and as quickly as possible, fueled the advance of high-speed internet and data services which helped this industry after it took a hit during the 2008 recession. However, demand for electrical equipment is expected to be on the rise through 2013 as more Americans gain access to disposable income and corporate spending increases, specifically on improving communication bandwidth capabilities. As the graphs in Figure 3.1.1 from the IBISWorld report shows, the demand for electrical equipment correlates very closely with the amount of disposable income consumers have in their pockets. This is an important market driver because it dictates that consumers see electronics as luxury items that become more of a want in times of need.
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Figure 3.1.1 Graphs displaying the correlation between electrical equipment demand and the amount of disposable income consumers have.
Reprinted with Permission (Pending) from IBISWorld
There has been a significant decline in the cost to purchase electronic components over the past few years, mostly due to competition with offshore jobs. Corporate businesses have sent many manufacturing operations overseas to benefit from cheap labor – and cheap products – to produce mass quantities of components, which has negatively affected electronic wholesalers in the U.S., who must in turn lower their costs to remain competitive. Another key factor to this industries success depends on the percentage of households that own at least one computer because; computers are made up of the wholesaled electrical parts and components that this industry produces. In addition, consumers with one or more computer in their house are much more likely to purchase other products that require similar electrical components.
This industry has been on the cutting edge of innovation for hundreds of years allowing it to reach a very mature time in its life cycle. IBISWorld defines a mature industry as one whose ‘revenue grows at the same pace as the economy, has established technology and processes on the market and has achieved a total market acceptance of product and brand’ (Harrison).
Surprisingly enough the companies that supply the electricity to power all of these high-tech devices are way behind their micro-counterparts in terms of updates, speed and reliability. The current power grid infrastructure in place does not allow for any communication between utility companies and their consumers, making it extremely difficult to provide a reliable service. Communication is on the rise and utility customers are going to need to create a significantly better channel for communication between themselves and their customers in order to supply the ever rising demand for electricity.
Innovative research and development will continue to expand the electrical device and parts field and in order for utility companies to keep up they will have
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to start implementing some of these developing technologies into their operations, which would be mutually beneficial for both industries (HighBeam Business).
3.2 Similar Products
Being informed on one’s energy usage is not a new concept by any means. There have been products out on the market for years that will report electrical usage of your appliances. Those interested in curbing their energy consumption must have a way to measure their current usage in order to decide the most effective course towards energy reduction. There are several tiers of home energy consumption monitoring: basic whole-home monitoring (classic electric meter-reading), circuit-by-circuit monitoring & individual appliance monitoring. These technologies are the various methods of measuring energy being consumed, in order to interpret the data and plan out how to curb energy consumption moving forward requires a platform for viewing the numerous amounts of data the measuring devices collect.
Houses typically come standard with an electric meter on the side, measuring the total power output of the house in kilowatt-hours (kWh). At the end of each month the utility company sends an employee out to measure the total amount of power the meter records and sends you the bill. Monitoring energy consumption through an existing house electric meter requires venturing to the outside corner of your house that contains the meter and recording the measurement displayed – monthly, daily, hourly, depending on how many data points the user is interested in recording. In practice, this method provides limited amounts of data that cannot be broken down any further than total house power output. This does not give the consumer any insight into which appliances are eating up the most electricity or which appliances are unnecessarily consuming power and wasting money.
Furthermore, the consumer must calculate the total energy savings themselves by recording each utility bill total and comparing total kWh and total cost to previous months. The average electricity user may find this laborious task not worth the short term savings on their power bill each month. A lack of information as to how people can adjust their electricity usage and no information on how much money it will save them provides little incentive for people to change their habits. Although the in home displays solve this problem, providing the customer with another gadget that will accumulate space on a countertop, where it could easily get misplaced or damaged and in such an event you are left with a bunch of additional plugins collecting energy data with no way of conveying that information to the consumer.
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This is a problem that is addressed with the in home display (IHD – an example is shown in Figure 3.3), which is a device that collects data from plug load monitors or other energy measuring devices scattered throughout the house and presents the information on an all-inclusive screen. Such as all the rest of tiers of in-home energy monitoring, the in home display has varying degrees of measurement starting from individual appliances to collecting entire house energy consumption data and displaying it on an additional device inside the home. Some IHDs act as a portable display that is linked to software on a computer, a server on the web, or a mobile phone giving the consumer multiple platforms for energy monitoring. The following diagram Figure 3.2 displays the block diagram for a typical home area network.
Figure 3.2 - Typical configuration for a home area network supporting energy measurements using current transformers. Reprinted
with Permission (Pending) from Energy Circle
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An independent touch screen monitor that collects data from appliance smart plugs can be seen as a redundant piece of hardware in todays wireless world. It is no secret that the incredible success of smartphones and tablets is due in huge part to Apps, the accessibility and innovation that has spawned from these pixelated buttons on our wireless devices provides developers a chance to provide users with total control of their entire lives with the swipe of a finger.
A study conducted by IEEE members in Omaha, Nebraska provided a thousand residents of the city with in home devices that would alert them during times of high electrical demand on the grid. The study was implemented to observe the effect of in home devices on power reduction. It was concluded that the IHD alone will not significantly curb electricity usage over a 30 day period. Participants candidly admitted that they paid more attention to the device in the initial 30 day period, in fact 10.5% of participants said they did not pay attention to the device after the first month (Alahmad, Wheeler and Schwer).
As the Omaha study showed, the in home devices did little to change behavior towards curbing consumer energy consumption, as interest decreased over time. This could easily be contributed to the fact that people had no incentive behind the reminder and further more they had to be in the room in order to know that the demand time was happening. Providing an app that consumers would have in their pocket alerting them at optimal times to turn off their power and allowing them the ability to remotely control devices will greatly improve the chances of seeing a behavioral change in energy consumption because this option requires little additional work on the consumers end. In addition, constantly updating the consumer on how much money they are saving by turning off that TV while they weren’t home will encourage consumers to continue curbing their wasteful habits so they can see those dollar signs add up!
3.3 Whole House Monitor : Pulse Sensor Fortunately, there are some products out on the market today that eliminate the need for manually checking your electric meter. By placing a pulse sensor that has the ability to wirelessly communicate directly on your electric meter, power drawn through the meter will be collected and sent to a server or in home display (IHD) where the consumer can access it. The pulse sensor measures the electricity that you are consuming by counting the electronic pulse made by the utility meter as it measures units. These sensors are common on various meters for measurement including electricity, gas, and water. However, these devices are limited in the fact that they can not determine whether power is going in or out they can only measure the amount of pulses the meter draws (Weliczko). Products on the market today that utilize this technology include the Blue Line Innovations PowerCost Monitor and the Wattvision. These systems place a clamp on the electricity meter – the PowerCost Monitor clamp is shown in the Figure 3.3 below with its accompanying IHD - that holds the pulse sensor and transmits the data over WiFi to a server, the Wattvision also has the optional phone app to monitor energy consumption on the go. Although, these products encourage whole home energy consumption reduction, they do little in terms of
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providing a breakdown of consumption throughout the house. They will also cost you a couple hundred dollars to purchase, on top of an annual subscription to access the data on their software or servers.
Figure 3.3 – Power Cost Monitor pulse sensor clamp shown on electricity meter with accompanying IHD. Reprinted with Permission (Pending) from
Energy Circle
3.4 Circuit by Circuit Measuring: The Current Transformer
Figure 3.4 Shows an current transformer monitoring system that attaches and measure every individual circuit in the house. Reprinted with Permission
(Pending) from Energy Circle
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The energy conscious consumer who is also electrically savvy can purchase a circuit-by-circuit monitoring system which measures individual house circuits at the breaker level and sends this data to a server which the consumer has access too. Installation of one of these systems requires removing the breaker panel and attaching current transformer (CTs) around each wire coming out of every circuit (as shown in the Figure 3.3-2 of the eMonitor system below), for this reason it is recommended that an electrical technician – or a competent electrical engineering student – installs the system.
These devices, CTs consist of a magnetic core and a secondary winding that creates a donut around the electrical wire coming out of a circuit breaker. Alternating current flowing through the wire induces a magnetic field in the core which in turn creates a proportional current in the secondary winding of the CT – shown in the turns ration equation below, the generated voltage due to current in the second winding is what the device ultimately measures (Energy Circle).
Calculated results are transmitted over a wireless medium such as WiFi or Zigbee to either an in-home display (IHD) or a server where the user can access the data on their computer or other internet enabled device.
Existing products such as The Energy Detective (TED) 5000 series (TED) and The Powerhouse Dynamics eMonitor (Energy Circle) collect data from current transformers placed on the homeowner’s circuit breaker box and display it on an in home display, these products also take it a step further and send energy information to a web server where the consumer can access the information online with their computer or other web enabled device.
As shown in Figure 3.4 above, these devices can seem unfriendly and messy to the average electrical consumer because they require a somewhat scary setup to those that are unfamiliar with electrical circuits, furthermore it is recommended that an electrician install these systems in order to prevent consumers from electrocuting themselves. Purchasing one of these systems that incorporates whole house monitoring with accompanying energy management software is not cheap and will run you a couple hundred dollars at least, the eMonitor retails for $500. These systems make energy consumption management a chore for the consumer, in regards to installation, which decreases the likelihood that energy reduction will be implemented.
3.5 Individual Appliance Measuring: The Analog Front End
The final tier of home energy consumption management is on the individual appliance level. Analog Front End (AFE) devices are plugged in between the wall outlet and the appliance they are measuring, which is plugged into the actual
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plug load monitor. These devices report the power consumption and operating costs of individual appliances, which is useful for discovering which electronics, are eating up the most amount of electricity in the consumer’s home. The most popular version of this basic system is the Kill A Watt® from P3 International shown in the Figure 3.5. This classic electric measuring device has an LCD screen which displays energy consumption in kilowatt-hours (kWh), just as the utility company does. This device also calculates energy cost per day, week, month and year based on local electricity rates, which can be programmed into the device. In addition the Kill-a- Watt® allows the user to check quality of power a device draws by monitoring voltage, line frequency and power factor. The latter is a useful nugget of information in order to determine if a device has gotten too old or is broken by drawing more power than necessary to perform the same function based on the manufacturer specifications (P3 International).
Figure 3.5 The classic AFE, the Kill A Watt® from P3 International
Reprinted with Permission (Pending) from P3 International.
Kill A Watt® is a fantastic product for the consumer who is interested in figuring out exactly how much power an individual product eats up because it is efficient, straight forward and affordable - priced at a moderate $23.99 on the P3 International website. The Watts Up? PRO Power Meter is another product on the market that measures individual appliance power consumption and reports on that individual appliances energy usage (Watts up?). The Belkin Conserve Insight™ is another product on the market similar to the Kill A Watt® and the Watts Up?, however it differs in these two products by providing a five foot long cord between the wall outlet and the LCD display and plug for the device, allowing the consumer to track energy usage of hard to reach appliance outlets such as washing machines or dryers.
Although the idea of being able to measure individual appliances is convenient, it lacks the connectivity in today’s wirelessly connected world. The novelty – and
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cost benefits of the Kill A Watt® wares off once the consumer has to move the device to multiple appliances and devices through out there house, all while manually keeping track of the measurements that the device takes. This product serves with good intentions, however it falls short in regards to integrating into everyday use on the consumer side because it creates more work for the user with little return over a short period of time.
However, today’s market for individual plug monitors has become incredibly diverse with products that offer a variety of different features including but are not limited too: multiple individual plugs that wirelessly communicate their energy usage to an in-home display (IHD) or a server where a user can easily access the information, real-time communication with utility companies on local rates to factor in real-time cost, and sensing phantom power and responding by cutting power supply to the stand-by device.
The makers of the Kill A Watt® and the Watts Up? Products both have editions of their individual plug load monitors that send information to an in home display. Envi by PowerSave Inc., the Modlet from ThinkEco are all AFEs that support multiple plugs which run about $30 on top of the cost of the hub software.
In order to curtail ones energy usage efficiently, there must be a way to measure the existing power being consumed and a platform to view the information in a way that will promote energy saving. Tracking old school style gives the consumer little to no insight on their electricity usage habits and how they can be adjusted to save money and energy. Furthermore, it is incredibly important that the installation is simple and does not require an electrical expert for setup and that the data is easily accessible to the consumer at all times. A complicated set up will likely discourage users from even bothering to think about home energy monitoring. It is important to provide an application that keeps the consumer actively involved in managing their home energy consumption, otherwise the slow return on investment will have minimal effects on inducing a behavioral change in the electrical user.
4.0 Hardware and Software Design Research
4.1 Brief Overview of Subsystems This section will be a brief introduction to the subsystems we intend for our device. These are the basic definitions of what we would like to see in each subsystem with no conclusions being drawn yet. The subsystems are listed as follows:
Main Device Hub/ Central Data Collection
Wall Units
Mobile Device App
Device Enabled Browser Based Software
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4.1.1 Main Device Hub
The main device will be used primarily as a data hub, sending and receiving the data transmitted from the wall units and uploading them to the internet. Through the main device we plan to host a Bluetooth Serial Port to receive the data from the wall units Bluetooth transceivers. Ideally we would like this serial port to host at least 6 separate devices on the Bluetooth network. The Bluetooth will be at the 2.4 GHz band to support the highest data transmission for this type of device. From there it will be stored on a microcontroller and sent out via Wi-Fi to the residents wireless router in order to be used on browser based software and hopefully mobile device apps. Figure 4.1.1 best demonstrates the flow of data we want to achieve from our design.
Considerations were made to use the IEEE 802.15.4 protocols or ZigBee and research suggests that this is the most common solution for energy metering in the home. However our goal is to utilize the Wi-Fi network of the user and there are many concerns with interference between IEEE 802.11b and IEEE 802.15.4. "A significant and measurable performance degradation of 802.11 results when the two networks coexist, leading to a throughput degradation of 802.11 by up to 80%" (Bahai). Using this information, we find it best to use 802.11b protocol in our main hub to ensure no interference between our device and Wi-Fi for the user. Figure 4.1.1 represents the flow of data through the main hub of the device.
Figure 4.1.1 Main Hub Block Diagram
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4.1.2 Wall Device The wall device is a key subsystem of SCHNAPS. The wall unit will be able to measure the amount of power being drawn from an outlet in the household that has been plugged into. The MCU's we have been researching work by taking in current and voltage data and processing the data through ADC. This data can then be used by whatever module is connected to the output. In most cases this is an LCD module that would display data locally, but our goal is to bypass local feeds altogether and use wireless technology to get that data sent directly to mobile devices and browser based software.
The Bluetooth technology we will be incorporating into the wall devices will be on the 2.4GHz band. This band allows for faster data transmission than sub 1GHz bands although the range will be limited to about 50 meters in total range. We feel that this allows for the greatest data rate transmissions while still covering areas of a household that contain the greatest power consuming appliances.
Figure 4.1.2 Data Flow of Wall Unit
Powering the wall device MCU's and Bluetooth can be achieved by creating a workable voltage for both modules. These devices need around 3.3 VDC to operate accordingly, and we can use a current transformer as well as several shunts to achieve this. Voltage will be regulated from this point allowing our modules to function. All of these components will be low current consuming
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devices to make sure they add negligible consumption on all lines they are installed on. Figure 4.1.2 exemplifies the basics of how signal and data will be transmitted through the wall unit.
4.1.3 Device Enabled Browser Based Software As no one in our group has the background to develop and manage a server, we are using a product named SitePlayerTM to enable our device to have Web and remote access. The SitePlayerTM accesses the web via Ethernet connection native to the device hardware.
The SP1 is connected to a host MCU where it will receive data to host on the website. The web data is uploaded to and stored directly on the SP1 module. This will be displayed using an object oriented programming language of our choosing. With little background in object oriented programming, we feel this is our safest solution in Web enabling our device and being able to meet time constraints will be met without limiting the goals of our project. A characteristic data sheet will be included at the end of this report for the SP1 module.
4.1.4 Mobile App The mobile app will be the last piece of our design. We want our mobile app to be able to track every aspect of the wall devices performance and integrate functionality with the wall device as well. The mobile device will be able to track all the metrics from the wall devices i.e. power consumption, carbon footprint, cost on each line and total cost. The app will also be able to produce alerts and notifications for the user. While most of these alerts can be user defined, some will be automated to help bring attention to energy waste and cost.
Alerts that will be made customizable will be confined to phantom power alerts and cost analysis. The cost analysis alerts will look at how much time the user has been drawing power on a certain line and let them know how much it has cost them in kWh to run appliances on this line. The user set phantom power alert will notify them after a set amount of time if a line is drawing phantom power from devices in standby mode and ask the user if they would like to turn off the wall unit to save power. The last notification will be automatic and a reminder to the user. It will remind the user about using power during peak demand times. Power companies want to reduce usage during peak times in order to prevent blackouts so they are going to be instituting higher rates during these peak demand times. This notification will help try to alleviate increased cost on the user and further strain on the grid during peak times.
4.2 Wall Device
4.2.1 Power Monitoring Microcontroller There are many power monitoring IC's available each offering a unique set of peripherals and quality of data that can be stored and used. The most crucial aspect of these is that the one we decide to use provides the most accurate and
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low cost impact to the design and lowest current consumption. There are three from those viewed, that the group has considered for the power monitoring. These are the Texas Instruments MSP430 based AFE253, the NXP Semiconductors ARM Cortex-M0 based EM773 and the Freescale Semiconductor ARM Cortex-M4 based Kinetis Family MK30DX256VLQ10. Table 4.2.1 lists various criterions that were used as first round comparison points.
Table 4.2.1 Power Monitoring MCU Comparison
As shown these devices have various features in design for. Size and cost were very important factors; these three were the most cost efficient for their dimensions. The range for the Flash memory and RAM are great though. The MK30DX256VLQ10 and EM773 are more geared toward LCD operation, most of their GPIO pins being able to operate LCD segments (NXP Semidonductor), (Freescale Semiconductor). Since our design is going to bypass LCD altogether
Model MSP430AFE253
(Digi-key) EM773 (Digi-
Key) MK30DX256VLQ10
(Digi-key)
Flash Memory
Size(kB)
16 32 256
RAM Size(kB) .5 8 64
GPIO 11 25 102
Core 16Bit 32Bit 32Bit
Clock Frequency 12Mhz 12-48MHz 100MHz
Data Converters 3x 24Bit ADC None 2x16Bit ADC
2x12bit DAC
Package 24 pin 33 pin 144 pin
Dimensions(LxWxH)
(in mm)
7.7x4.5x1.2 7x7x.85 (NXP
Semidonductor) 20x20x1.4 (Freescale
Semiconductor)
Cost(for a single unit)
$5.54 $5.04 $12.34
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the MSP430 device reduces the size and number of unneeded pins.
Figure 4.2.1 Example Block Diagram of MSP430AFE253 Application
Courtesy of Texas Instruments
The MK30DX256VLQ10 has the highest memory and fastest clock and includes ADC as well as DAC converters. These converters however are lower in quality at 16Bit for the ADC converters, than the MSP430 which has a higher resolution with 24 bit. The EM773 does not even come with these converters, meaning we would have to purchase additional parts to account for this as well as the space needed to account for the external components. The EM773 has been ruled out for this fact. The MK30 features the highest clock frequency, this however leads to it consuming more power for peripherals than the other two devices. The MK30 is not one we would use in our final design because of how large it is compared to the other two devices. The extra memory would be an added bonus
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as well as the faster clock and larger core memory, but the extra pins are not needed and the design requires minimization of the amount of space needed in the device.
The group has decided from what we have found that our requirements are met by the MSP430AFE253. The unit is small enough to fit into our design requirements and its cost is relatively low. The device also operates at 220 μA at a VCC of 2.2V at an operating frequency of 1MHz. This is considerably smaller than other devices viewed (Freescale Semiconductor), (NXP Semidonductor). The MSP430 device also has higher resolution on its ADCs, giving better accuracy readings for device measurement. Accuracy is rated at .1% at 2000:1 current ratings. An example block diagram is provided as Figure 4.2.1. (Texas Instruments)
It is important to not the characteristics of the MSP430AFE253. The device has 4 power modes, each with a different associated voltage level and current consumption. The values listed in Figure 4.2.1-1 give the absolute values for input and power into the device (Texas Instruments). These values should not be exceeded for the device to operate at full efficiency.
Figure 4.2.1-1 Recommended Operating Conditions and Ratings for MSP430AFE253 Courtesy of Texas Instruments
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Figure 4.2.1-3 Voltage versus Frequency for the MSP430AFE253 Courtesy of Texas Instruments
Figure4.2.1-4 Current characteristics For MSP430AFE253 in active mode Courtesy of Texas Instruments
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The device also operates more effectively at different voltages. The voltage helps drive the crystal oscillator and makes the device operate up to its master clock speed of 12MHz. The graph provided by Texas Instruments in Figure 4.2.1-3 shows how voltage affects the ability of the operating frequency to change (Texas Instruments).
The only modes we should be concerned about for the device are the active modes, mainly the full active mode. The full active mode will be utilized as the device will constantly be displaying data while connected to the line. The current consumption varies as a linear function of frequency. Figure 4.2.1-4 shows the relations between frequency, voltage and current (Texas Instruments). It also displays the values for typical values for 1 MHz and 12 MHz.
4.2.2 Bluetooth Transceiver for Wall device Model CC2541 (Texas
Instruments) CSR1010 (Cambridge
Silicon Radio Limited)
Data Rate Up to 2Mbps Not listed
Power 0 dBm 7.5 dBm
Sensitivity -99 dBm -92.5 dBm
Voltage Supply 2-3.6 V 1.8 - 3.6V
Current RX 20.2 mA 16 mA
Current TX 18.2 mA 16 mA
Memory 256kB Flash, 8kB RAM 64kB Flash, 64kB RAM
Package 40 Pin 32 Pin
Dimensions(mm) 6.15x6.15x1.0 5.25x5.25x.8
Cost $5.75 $2.74
Table 4.2.2 Quick summary of Bluetooth Devices
There are so many solutions for Bluetooth connectivity on the market, finding the most appropriate one was a little hard. With the advancement of Bluetooth technology however the searched started at finding the most energy efficient Bluetooth modules. The Bluetooth low energy or Blue tooth 4.0 technology is made for all low energy consumption needs. Bluetooth v4.0 introduced low energy technology to the Bluetooth Core Specification, enabling new Bluetooth
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Smart devices that can operate for months or even years on tiny, coin-cell batteries (Bluetooth SIG). This level of power consumption is perfect for implementing the low consumption circuit we want to implement with our design.
The group has decided between two possible Bluetooth devices, the CC2541 from Texas Instruments and the CSR CSR1010. Both devices are both Bluetooth 4.0 low energy devices. These devices consume less than 20mA of current and operate at 3.3V input voltage. Table 4.2.2 is a short list of qualities the group used to determine which would be the best device to use.
While price, size, and power consumption are still the biggest factors the group considers, everything on the table was carefully considered before making a final decision. The CC2541 has greater sensitivity and lower power output during its active mode and the 2Mbps is uncommon for Bluetooth 4.0 devices (Bluetooth SIG). The CSR1010 has its data rate unlisted in its data sheet but we can assume that the max rate is 1 Mbps per the Bluetooth 4.0 specifications (Bluetooth SIG).The groups wants our device capable of keeping the user fully updated at anytime so the fastest data rate is our preference.
Figure 4.2.2-1 Example Application Schematic Courtesy of Texas Instruments
The current being consumed from each device during receiving and transmission are well within acceptable ranges. The CSR1010 far surpasses the CC2541 by 4.2mA during RX and 2.2mA during TX. Reading through the CC2541 datasheet
25
the group found that a particular Texas Instruments power supply is available, the TPS62730, that puts the RX and TX values at 14.7mA and 14.3mA, respectively (Texas Instruments). This makes the CC2541 much more viable for our design.
Figure 4.2.2-3 Comparative Current Consumption Using TPS62730 in Low Energy Mode Courtesy of Texas Instruments
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The last thing to consider was the RF connections to the devices. These connections require a balun and an antenna to transmit data. A balun converts an unbalanced signal into a balanced signal or balanced to unbalanced depending on application. The CSR1010 hosts a single RF port with an internally placed balun matched to a 50 ohm port for the antenna (Cambridge Silicon Radio Limited). The CC2541 does not come with an internal balun but Texas Instruments provides documentation on how to construct a balun for this specific device (Wium). Texas Instruments also has material covering how we could design our own antenna for use with the CC2541 and how we should match it to the balun (Texas Instruments). The balun and antenna being of our own design drive the price down, however small, but allow us to come up with an antenna that will complement the structure of the wall unit to reduce size.
With all factors considered we have chosen to go with the CC2541. The group believes we will be able to more adequately accomplish our design goals with the CC2541, with its increased memory and data rate, despite its cost. Using this device coupled with the power supply mentioned above we will see lower power consumption than that of the CSR1010. The amount of supplementary materials provided by Texas Instruments for the CC2541 also makes it really configurable for our design and this is why we consider it the better device for our design. Outlined in Figure 4.2.2-1 is an example application schematic.
Our main concern with the Bluetooth is that it acts in its lowest power consumption mode. The CC2541 has different current consumption during transmission and receiving data and at different frequencies. Frequency dictates how much current is consumed because it determines how powerful the output signal is. Figure 4.2.2-2 gives the typical characteristics during use while operating in low energy mode (Texas Instruments).
To obtain the lowest current consumption though, we have to use a special power supply, the TPS62730, shows a considerable drop in the amount of current consumed during TX and RX modes. This power supply is also capable of operating in the Bluetooth low energy mode which provides a data rate of 1Mbps, suitable for our needs of data transfer. Figure 4.2.2-3 shows comparative values of TX and RX modes to that of the typical values in Figure 4.2.2-2 for the CC2541. These values are what made us choose to use the CC2541. (Texas Instruments)
4.2.3 Power Supply The power supplies will be supplied by power form the mains line. The power needs to converted down to a usable 3.3VDCfrom 110VAC. This can be achieved using a capacitor based power supply. The supply filters down the mains signal into a usable DC signal coupled with a 3.3V low power regulator IC driven at 12mA (Texas Instruments). The regulator part is the TPS77033 able to power the MSP430. Figure 4.2.3-1 shows this power supply unit. A separate switching based power supply may be needed to drive the Bluetooth requiring slightly more current to drive the RF transmission. This power supply circuit will
27
add the TSP62730 to allow the lowest current consumption from the Bluetooth device. This type of power supply is displayed in figure 4.3.2-2. (Texas Instruments)
Figure 4.3.2-1 Capacitive Power Supply for MSP430AFE253 Courtesy of Texas Instruments
Figure 4.3.2-2 Switching based power supply to power additional components Courtesy of Texas Instruments
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Figure 4.3.3: Full Wave Rectifier
We had issues with the power input that was recommended by ti. They have the
resource of having resistors that never overheat and can take as much current as you
can give.
The figure above gives a circuit diagram of a full wave rectifier using a bridge
configuration. A full wave rectifier allows current to flow during both parts of the input
sine wave input. Assuming Vx is the same for all of the diodes, when Vin > 2 . Vx, D2
and D4 are forward biased and D1 and D3 are reverse biased. Current then flows from
Vin (A) through D2 through R and then through D4 and back to Vin (B) (Figure 5(a)).
Again, when Vin < -2 . Vx, but in the opposite polarity, D1 and D3 are forward biasedand
D2 and D4 are reverse biased. Under this condition, current flows from Vin (B) through
D3 and then through R and D1 and back to Vin (A) (Figure-6(b)).
Under both conditions for Vin being high . Vx and Vin are low and Vx, which is the
current flowing through the resistor R is in the same direction. Even though Vin changes
polarity, the voltage across R remained the same. The lower picture gives Vin and Vout
as a function of time. Vout is the same as Vin when Vin is high . Vx except it has been
reduced in amplitude two diode drops of Vx. When Vin is low. Vx, then Vout is the
inverted version of Vin Vx except it also has been reduced in amplitude by two diode
drops of Vx.
Through these two ideas, we settled on a middle ground with is shown in the picture
below which implements the main points of the recommended circuit but implements the
full wave rectifier above to make a circuit that steps down the power appropriately with
realistic parts.
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Figure 4.3.3: Final Power Input Design
4.2.4 Antenna and Balun
Figure 4.2.4 Comparison of Reference Balun to Murata Balun Courtesy of Texas Instruments Permission Pending
The antenna will be of our own design, a simple dipole antenna outlined in the design notes provided by Texas Instruments for the CC2541. The antenna needs to be matched to the balun. The group will want to design the antenna to be matched to a 50 ohm design, this being a typical value for RF devices. As well the balun supplemental design notes suggest an impedance of around 50 ohms. Texas Instruments also provide application notes for a balun produced specially for the CC2541 (Kervel). This balun is produced by Murata and is an alternative
30
to building our own balun. It is already matched for a 50 ohm line. Matching the antenna will be difficult however, but the CC2541 development kit employs a network analyzer between the balun and the created antenna. Achieving a matched line will ensure the highest quality signal and the least amount of data loss.
As stated previously, Murata makes a balun specifically for use with Texas Instruments low power Bluetooth devices. The balun is made to match a 50Ohm terminated line. "The balun replaces 9 discrete 0402 components in the recommended discrete balun / filter design". This balun will significantly reduce the amount of materials needed to match the RF ports to the antenna. Figure 4.2.4 compares the Texas Instruments balun reference design to the Murata balun. (Kervel)
4.2.5 Current Transformer The MSP430 input lines cannot support the current and voltage from the mains. The inputs need to be tuned down to 500mV from the standard line voltage of 110V. The current transformer used in the implementation page by Texas instruments calls for a current transformer with a turns ratio of 2000:1 with a rating of 100A (Texas Instruments). There are not that many companies that provide this device. Through Digikey there is one such company, Nuvotem Talema. The part is the AP-2000 current transformer.
4.3 Main Hub
4.3.1 T.I. Metrology Texas Instruments Inc. is one of the world’s oldest and largest semiconductor chip manufacturer in the industry. Through creating market leading digital signal processors and analog semiconductors, which create a medium for media content and other files to get transmitted over a network, TI has expanded into a diverse network of its own creating technologies that are the backbone of hundreds of our own technological devices (Cother, 2013). Among the wide range of technologies that TI creates electronic parts for, the company shows a vested interest in the future of electricity metering. Supplying the widest variety of smart grid metrology application processors, communication systems and energy-meter ICs, TI is prepared to meet the demands of the changing electricity market (Texas Instruments Inc., 2013).
Smart Grid Solutions is TI’s response to the changing energy market around the globe fueled by market forces and regulation driving energy usage reduction. Two way communication between the utility company and consumer is the greatest task that must be conquered. Soon the wires running into your house will not only deliver electricity to power your home but it will also act as a two – way communication channel for data transmission between you and your utility company, known as Power Line Communication (PLC) (Texas Instruments Inc., 2013). According to the Edison Electrical Institute, a smart meter will show up on
31
your house sooner rather than later (Queen, 2011). The two way communication will be implemented on the Advanced Metering infrastructure (AMI) and support time based rates, real – time data, and a LAN interface. These smart meters will breakdown how much power is being consumed and what time consumption takes place. This information will be readily available to the utility company and those consumers that have home area network interfaces. This is what the future of energy looks like, utility companies all over the globe are finding it imperative to switch to this smart grid in order to keep up with energy demand as it shows no signs of slowing.
4.3.2 Electrical Standards Required by Utility Meters TI family of microcontrollers and AMIs have been developed to support the Smart Grid applications that are driving the energy revolution including, dynamic pricing, demand response, remote control power on/off, outage management, reduction of technical losses and network security. Network security will be a parallel concern as the electricity grid grows. Smart meters being deployed will be directly responsible for measuring the amount of electricity being consumed in a household, this means a high level of accuracy and consumer privacy is expected from the smart meters themselves and the network they make up. For this reason all Texas Instruments Smart Meter products fall within the specifications of standardization of accuracy for the American National Standard for Electrical Metering (ANSI) when used for revenue and the IEC standardization of electro technologies within the electrical field internationally (Texas Instruments Inc., 2013).
The required precision required for utility and sub-metering varies based on function. According to the Energy Harvesting Solutions article presented by DigiKey, utility meters that deal with billing customer electricity usage obviously require much stricter accuracy guidelines (as tight as 0.1 percent error) by the two institutions mentioned above – ANSI and IEC. Devices that are involved in sub-metering are not required to be as precise (accuracy usually around 2 percent) because they are not directly involved in the billing process (Goldberg, 2012).
Our use of AFEs in our project for power measuring, will not be directly involved with the billing process. Therefore, the level of accuracy and precision does not have to be as strict. However, because we have chosen TI’s family of meter IC’s we will still experience the benefits of highly precise electricity measurements.
4.3.3 The Internet of Things
The Home Area Network associated with the Advanced Meter infrastructure is another application of the future that TI’s family of electronics is fully equipped to handle. These devices make up a network commonly referred to as the Internet of Things (IoT) defined by TI as ”an intelligent, invisible network fabric that can be
32
sensed, con- trolled and programmed. IoT-enabled products employ embedded technology that allows them to communicate, directly or indirectly, with each other or the Internet (Chase, 2013).” TI’s family of microcontrollers has a group of chips that perform energy measurements and calculations on a single circuit board intended for Analog Front End use, the MSP430AFE2xx series is for individual appliance energy measurement. The microcontroller on board performs calculation and also has an SPI interface for transmitting collected data to a central hub processor.
Figure 4.3.5-1 Functional block diagram of the MSP430F6638 Courtesy of Texas Instruments Permission Pending
This encapsulates the basic elements of our energy measurement data collecting network: an analog front end device consisting of a current sensor and analog to digital converter to collect energy measurements, a separate microcontroller to perform energy calculations (the MSP430AFE2xxx is a single chip solution that houses both ADCs for measurement and an MCU for power calculations), and a host processer to collect, interpret and send data to either an LCD display or other interface where the user can access the data (Figure 4.3.3).
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Figure 4.3.3 Basic elements that make up the smart home area network for measuring electricity consumption Reprinted with Permission Pending from DigiKey
4.3.4 Metering Devices that Apply to our Project
Figure 4.3.4 Block diagram of the master and slave processors, the MSP430F6638 and the
MSP430AFE, respectively Courtesy of Texas Instruments
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Our project requires AFE’s that have the capability of measuring power consumption using ultra low power and have the ability to send the information wirelessly. It also requires a hub for the information to get sent to, the host processor. We need a host processor that has is able to process data and interpret power calculations.
In TI’s mission to expedite time to market the MSP430AFE2xx has a microcontroller partner to enable the full scope of energy management capabilities, the MSP430F6638 is a highly – integrated electric meter solution. The metering family of TI has a variety of different tools and resources for developing, testing and implementing energy metering.
The latter MSP deals with the application layer of metering and acts as the host processor. There is only one host processor that will be the ‘master’ of the various ‘slave’ metrology processors otherwise referred to as the analog front ends. The two devices will communicate data to each other through their through digital isolators via a serial peripheral interface (SPI) or universal asynchronous receiver/ transmitter (UART) (Chase, 2013). The block diagram of the two set up together is shown in Figure 4.3.4, the blue boxes at the bottom of the dotted line represent the connection of the two devices.
4.3.5 The Host Processor
Figure 4.3.5-2 Displays the 74 I/O pins on the MSP430F6638 Courtesy of Texas Instruments Permission Pending
35
The MSP430F6638, functional block diagram shown in Figure 4.3.5-1, is an ultra-low power consuming microcontroller that requires a low supply voltage ranging from 1.8V to 3.6V, sticking with the low power consumption theme. There is only a 3 microsecond delay when waking up from standby mode which will allow for real-time reports on selected appliances. The device is packed with a powerful 16 – Bit RISC architecture, extended memory and up to 20-MHz system clock makes it an exceptionally fast processor. The device contains a 12-bit analog-to-digital converter (ADC), comparator for background energy processes and up to 74 I/O pins – schematic of I/O pins shown in Figure 4.3.5-2. The first four registers are R0 to R3, are dedicated to specific functions while the remaining registers are all purpose, the register labels are shown in datasheet.
4.3.6 Communication with the MSP430F6638 Seeing as the demand for electricity only continues to grow, rapid deployment of energy saving technologies is necessary. TI accommodates for this by supplying every kind of end to end wireless solutions that are designed to be easily implemented onto their microcontrollers. Our purposes will employ the use of Bluetooth low energy technology, to stick with our theme of reducing energy. Moreover, utilizing various wireless technology to create a network of stand-alone AFEs that report individual appliance energy usage to a central hub that will upload the data to a platform that the consumer can access, provides an environment that gives the user more control over their energy usage than ever before.
Transmitting data from the application processor can be done over either of the two universal serial communication interfaces (USCIs). These communication interfaces create a full duplex portal for two-way wireless communication and data collection between connected devices throughout a home network. As mentioned, communication between our master/slave processors will be conducted over Bluetooth – discussed in detail later on. Figure 4.3.6 is a block diagram of the intended network setup between the analog front end device, host processor and the server.
In order to send the collected data to a server, first of all we must set up a server. For the purposes of saving time and focusing on bigger parts of the project we have chosen to bypass creating our own Internet Protocol for our server to house the data. We are able to accomplish this through NetMedia's SitePlayer. There is always a balance in life, and the code the TCP/IP code that is lost on the software side is picked up on the hardware side, in order to communicate with the SitePlayer (TM) we must embed the micro-controller with code that creates a gateway for communication between the two devices (Schoof, 2012).
Communication between the micro controller and the server will utilize the second USCI port of the application processor. The most optimal form of communication to the server is simply to solder the two together. Although we could create another wireless bridge from the host MCU to the server, this would require setting up a second network and run the risk of unnecessary
36
communication failures. There is also the option of feeding the information from the main hub to the server through the USB serial port of the microcontroller to the computer, which is also connected to the server. This method will be useful during testing ultimately, hardwiring the devices together is not only the most reliable form of transmission, but it also cuts down various pieces that we will need.
Figure 4.3.6 – Block Diagram portraying communication between devices. The blue line represents the wireless connection of the Bluetooth
communication protocol and the black arrows represent wires connecting the devices.
4.3.7 Bluetooth Node The CC2541 uses Bluetooth low energy protocol 4.0 in a single mode. This allows it to only communicate with other devices of the same protocol. Bluetooth 4.0 is available in a dual mode as well which handles both Bluetooth 4.0 and Bluetooth legacy protocols. The dual mode uses more power than the single mode and dual mode was considered for the design for its compatibility but the power consumption for devices viewed was typically 4 times the amount of the single mode devices.
The main hub will be using the CC2541 run as a master device. Bluetooth protocol supports up to active slave devices and 255 devices in sleep mode (Bluetooth SIG). This makes it possible to realize our goal of having 6 active devices reporting power metrics. Critical data for the CC2541 can also be found in section 4.2.2, concerning the Bluetooth device being used for the wall plug unit.
MSP430
AFE
Bluetooth
MSP430
F6638
SitePlayer
Server – Web Access
Hard
Wired
Ethernet
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4.3.8 SiteplayerTM The Siteplayer Module will allow us to provide a device hosted web server for the user. " SitePlayer handles web protocols and Ethernet packets independently of the device processor. Web traffic does not affect the device processor, which also adds a measure of security. Communication between SitePlayer and the device is accomplished through objects sent through a standard two wire serial port" (NetMedia, Inc).
Figure 4.3.8 Siteplayer Functional Block Diagram. Reprinted with Permission (Pending) from NetMedia.
With the Siteplayer, we can actively host web data for the main hub to display over the internet and through object oriented devices. We would like to create the app data from this device as well displaying it through web capable devices. The group decided to use the Siteplayer after being recommended it as a solution to our inexperience with designing and setting up server operations. The device seems highly configurable and operates separate of the host MCU, making it a perfect addition to easing the burden of all the data processes being handled by the MCU. Figure 4.3.8 is the functional block diagram include in the documentation for the Siteplayer SP1 module.
4.3.9 Changes to the Main Hub
Contrary to popular belief, nothing ever goes the way it is planned to go on
paper. We tried the MSP430F6638 and the EK-TM4C123 and both
microcontrollers failed for various reasons. Most issues with them were the code
required to deal with them were too complicated for three electrical engineers but
additionally, the MSP430 was simply not a good fit and our research in this area
didn’t tell us this due to its lack of second level thinking. God bless Maeve but
she didn’t have a clue what she was doing when she was assigned this portion of
the project.
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The board that we ended up using for the main controller is the Tiva-C
Connected Launchpad SW-EKTM4C129XL, pictured in Figure – 9, from Texas
Instruments. This microcontroller will act as the systems main hub,
communicating with the various plug-in devices via Bluetooth connections,
gathering their power usage information and posting this information to a
webserver where the user can access it using a web portal. This board offers out
of the box internet connectivity, just requiring an Ethernet port connection from
the board to a router and a power supply to get the board online. We chose this
board for both its capabilities and its ease of connectivity. In order to create a
network of home appliances the system must be simple to implement in order for
it to fit into people’s everyday lives.
In addition to quick internet connectivity this board has the ability of the most
basic MSP430 Launchpad, which fulfills the requirements of our project. In order
to communicate with the plug-in devices this board has multiple SPI and UARTs
which will be the interfaces that we use in order to have the board communicate
through Bluetooth.
This board acts as the messenger between the internet server and the plug-in devices. Being the master in the master-slave chain of command. The board is able to pull information when it is needed in addition to sending an hourly update of information. Another advantage of this board having internet connectivity is that we do not have to store information on it for a long period of time. The board is equipped with 256KB of SRAM, meaning the board will be wiped every time the main controller is powered off. However, it will also be wiped every time the controller sends information to the webserver. This is a useful feature to ensure the safety of all the information
4.4 Website Information
The look and feel of the website is simple. It needs straightforward text without much extra diction, a user-friendly naviation bar at the top of every page. Once logged in you get to the archived user pages with the sidebar of easynav links to help get them from one page to another. The website should ooze confort with easy to read fonts and colors that massage the eyes. And with the help of the SitePlayer Objects, should have some pretty fun applications to display their data in very accessible, easy to read designs.
4.4.1 Projected Look and Feel
The home page is very much a resting hub for the customers can have their current questions answered as well as find out what Dukes current rates are for signing up. If there have been changes or updates to the product or website on the SCHNAPS side it will be posted here as well. It’s also important to advertise
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a little bit here. While not everyone who visits the main page is a SCHNAPS consumer yet, everyone who visits is a potential customer.
SCHNAPS
‘Your Key to Home Monitoring’
Home Login About us Contact
Welcome to Schnaps.
If you have any questions please feel free to ask us.
Today what’s exciting is we are realeasing our website for you to monitor your power consumption. It’s a really exciting step for you to save money and be more prepared during a blackout.
Duke Energy is currently Offerring a whole new set of deal to go along with
its minismartmeter sells.
And Don’t Forget : It’s inefficient not to go with SCHNAPS
Figure 4.4.1 Projected Website Home Page appearance
Logging in is a page of its own. While the SitePlayer is known to have very high standards of security, a login screen can mess up all of that. See component testing (page 10). The username and password will be chosen for each account prior to them buying and being issued a product. They are not changeable.
SCHNAPS
‘Your Key to Home Monitoring’
Home Login About us Contact
Figure 4.4.6 Projected Website Data Page appearance
Username: ________________
Password:
_________________
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The Data page is the home page for once you log into the SCHNAPS database. Of course, it is named appropriately as is provides all the data. A pie chart is one of the Objects that the SitePlayer provides and is very easily read. A couple of Options should be available for the pie chart. While each section is devided by device, the information that can be shown should be able to be shifted such that the results are reflective of Monthy Average or Current power consumption. Beneath the chart is a table that has each device shown broken down to different categories. Shown will be current power output, the monthly average, per unit cost and the monthly cost of each device. Per Unit cost should be the same for each device and may be omitted.
SCHNAPS
‘Your Key to Home Monitoring’
Home Login About us Contact
Data
Contract
History
Current Power
Output
Monthly Average
Per Unit Cost
Monthly Cost
Device 1
Device 2
Device 3
Device 4
Figure 4.4.2 Projected Website Data Page appearance
Status page is very useful during a power outage. While it is true that it is much more difficult to get on the internet during a power outage with a powerless computer and router/modem combination. But if you can find a way to access the internet then SCHNAPS will tell you what phase in the recovery process you are at. SCHNAPS response program is usually at the Normal phase of its relief effort. This means that no current issue is plaguing your grid. Once a blackout is
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sensed, SCHNAPS immediately alerts your power provider. And the status switches to notified. Once Duke receives this they are able to log into SCHNAPS and alter the status to Acknowledged. Typically it shouldn’t stay on this stage long, and once Duke diagnoses a problem they change the status to fixing and eventually back to normal mode. Once Duke has an estimate of how long until power is restored, there is a spot they can post that as well but once power is restored you will probably know.
SCHNAPS
‘Your Key to Home Monitoring’
Home Login About us Contact
Data
Contract
Status
History
(Color Coded for what stage it’s on)
Figure 4.4.3 Website Status Page appearance
SCHNAPS
‘Your Key to Home Monitoring’
Home Login About us Contact
Schnaps was developed by a group of origionally four college students,
while one of the four had to drop the project for health reasons he is
still considered a bright star for his help in coming up with the idea and inspiring the design. The four are: Shawn McDorman, Maeve
Kasey and Nick Mulqueen.
When SCHNAPS was developed it filled a coulple of needs. Blackouts
response was slow and innificient, consumers could only view their
power expenditures when a bill came and power was being used in large quantities without remorse. SCHNAPS steps in and provides an
efficient system for communication between devices and power provider during a blackout.
Figure 4.4.4 Projected Website About Us Page appearance
Normal Notified Acknowleged Fixing Estimated Restore Time
Current
Status
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The Contact page is brief. It simple has contact information of both a SCHNAPS representative and Duke Energy. (if other energy companies are applicable then they will be listed as well).
SCHNAPS
‘Your Key to Home Monitoring’
Home Login About us Contact
Figure 4.4.5 Projected Website Contact Page appearance
The Blackout page is a page reserved to document power outages to make each consumer better informed. While just about everyone knows that power outages are more likely to occur in the summer, this will put data to the paper that willclear all doubt. This page tells the time out, time in and elapsed time for each blackout.
SCHNAPS
‘Your Key to Home Monitoring’
Home Login About us Contact
Data
Contract
History
Figure 4.4.6 Projected Website History Page appearance
Date Time Out Time
Restored
Elapsed Time
Blackout 1
Blackout 2
Blackout 3
Schnaps
Contact
Number:
Email:
Duke
Contact
Number
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4.4.2 Actual Website Look and Feel
The website evolved mostly based on what we could and could not do. For example since we no longer were using the sightplayer for its sightobjects and easy graphics we were no longer able to easily convert the data into graphs and charts etc. The colors went from the jouvenile colors of our Alma Mater (black and gold) to the adult variations of green hues with white accents. Some things were cut for various reasons. The Logging in page was deemed moot and excessive and was replaced by just having a log in widget on the home page. Since our project migrated from the blackout reaction protocols to simple knowledge gathering the status page was eliminated. The history page was probably one of our least favorite pages and we decided to omit it from the final project. There is an aspect of history in the actual device page but that is a very small part of what it was. while other things like the home page were simply varied to include logo and headers that fit the company we attempt to portray. The about us and contact page were merged into one congruous page with contact information and a brief outline of each member. And out monitoring page was simplified into a simple number depicting the output each device outputs at a single time. The final result is below.
Figure 4.4.8 Actual Website Home Page
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5.0 Project Prototype Construction and Code
5. 1 Parts Acquisition and Bill of Materials The parts will be ordered mainly from Digikey for cost and convenience of receiving parts in on bulk order. The Bill of Materials was constructed using supplemental material provided by Texas Instruments and NetMedia. The parts listed are used in evaluation and application schematics. All permissions and for materials have been requested by their respective companies some with permission pending and will be included in the report as the official bill of materials to prototype our devices. This will not be the final bill of materials as some components may be deemed unnecessary and some components may be added to increase functionality of the device. Tables 5.1.1 through 5.1.3 are the bill of materials provided with each device and are labeled accordingly.
Part name Pcs/unit Description
Manufacturer Part number
CC2541 1 2.4 GHz SoC TI CC2541
C_0402 0 Capacitor, general, 0402; Do not mount
C_100N_0402_X5R_K_10 5
Capacitor, 100n, 0402, X5R, 10%, 10V Murata
GRM155R71A104KA01D
C_12P_0402_NP0_J_50 2
Capacitor, 12p, 0402, NP0, 5%, 50V Murata
GRM1555C1H120JA01D
C_15P_0402_NP0_J_50 2
Capacitor, 15p, 0402, NP0, 5%, 50V Murata
GRM1555C1H150JA01D
C_18P_0402_NP0_J_50 2
Capacitor, 18p, 0402, NP0, 5% 25V Murata
GRM1555C1H180JZ01D
C_1N_0402_NP0_J_50 1
Capacitor, 1n, 0402, NP0, 5%, 50V Murata
GRM1555C1H102JA01D
C_1P0_0402_NP0_C_50 3
Capacitor, 1p, 0402, NP0, +/-0.25pF 50V Murata
GRM1555C1H1R0CZ01D
C_1U_0402_X5R_K_6P3 2
Capacitor, 1u, 0402, X5R, 10%, 6.3V Murata
GRM155R60J105KE19D
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Part name Pcs/unit
Description Manufacturer
Part number
C_220P_0402_NP0_J_50
1 Capacitor, 220p, 0402, NP0, 5%, 50V Murata GRM1555C1H221JA01D
C_2U2_0402_X5R_M_6P3VDC
1 Capacitor, 2u2, 0402, X5R, +/-20%, 6.3V
Murata GRM155R60J225ME
L_1N0_0402_S
1 Inductor, 1n0, 0402, Monolithic type, +/-0.3 nH
Murata LQG15HS1N0S02D
L_2N0_0402_S
2 Inductor, 2n0, 0402, +/-0.3 nH Murata LQG15HS2N0S02D
L_3N0_0402_S
1 Inductor, 3n0, 0402, Monolithic type, +/-0.3 nH
Murata LQG15HS3N0S02D
L_BEAD_102_0402
1 EMI filter bead, 0402 1k ohms Tape GHz Band Gen Use
Murata BLM15HG102SN1D
R_0402 0 Resistor, general, 0402; Do not mount
R_10K_0402_F
2 Resistor, 10k ohms, 0402, ±1% Koa RK73H1ETTP1002F
R_2K7_0402_F
1 Resistor, 2k7 ohms, 0402, ±1% Koa RK73H1ETTP2701F
R_56K_0402_F
1 Resistor, 56k ohms, 0402, ±1% Koa RK73H1ETTP5602F
SMA_SMD 1 SMA connector, straight SMD-mount Hus-Tsan Group Taiwan
SMA-10V21-TGG
SMD_SOCKET_2x10
2 SMD pinrow socket, .050 spacing, 2x10
Samtec SFM-110-02-SM-D-A-K-TR
X_32.000/10/20/40/10
1 Crystal, 32.000000MHz, FA-20H, 10.0pF, +/-10ppm, (FTC: +/-20ppm at -40/85C), 40ohms
Epson Toyocom
FA-20H, 32MHz, 10PPM, 10pF, -40/+85C, 40ohms
X_32.768/20/50/40/12
1 Crystal, 32.768 kHz, 12.5pF, 20/50 ppm,SMD package
Epson Toyocom
MC-306
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Table 5.1.3A/B CC2541, BOM for MSP430AFE2XX Courtesy of Texas Instruments Pending Permission
5.2 PCB and Assembly Information
The PCB layout will be constructed using Cadsoft Eagle PCB software. As of now the group members are very limited in their skill with eagle and other PCB schematic programs. We chose to use Eagle because the campus computer lab has access to Eagle software and Eagle also has a freeware version available. This will allow us to edit schematics and at home if need be. Schematics of each device will be included on this report with permissions from each manufacturer. These will help us determine how to assemble our prototype before the final PCB is to be drawn using Eagle. Figures 6.2.1-6.2.4 depicts the schematics used.
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Figure 5.2.1 MSP430F6638 Evaluation Schematic Courtesy of Texas Instruments Permission Pending
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Figure 5.2.2 MSP430AFE253 Evaluation Schematic Courtesy of Texas
Instruments Permission Pending
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Figure 5.2.3 CC2541 Evaluation Schematic Courtesy of Texas instruments
Permission Pending
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Figure 5.2.4 SiteplayerTM Development Kit Schematic Reprinted with Permission (Pending) from NetMedia
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The assembly will be custom made out ABS plastic. After finding the exact dimensions needed to house our wall units and main hub, the group is going to shop around for the best price for ABS plastic housings. There are many manufacturers and finding one that also includes PCB printing and stamping seems to be the best value and offers the greatest convenience to the final product.
Currently the group is working on putting together a full scale Solid Works model. This will allow us to plan the exact look and dimensions of the assemblies. This coupled with our Eagle Schematics will be the last step in prototype development before the final product is produced.
5.3 Final PCB Information
One of the most important parts of the wall device is the printed circuit board that will
house all the circuitry and logic devices. We teamed up with CadSoft for their affordable,
easy to use tool for designing our printed circuit board and Element14 for printing the
circuitboard. Eagle is fairly widely used and there are even free tutorials online to learn
how to use it professionally. It is award winning and highly recommended. The best part
of the program is the way it simplifies Schematic Capture, Board Layour and Autorouter
functionalities. Element14 has massive Eagle libraries from the places we planned on
ordering our parts from (AVX, murata, and Vishay) along with many others. But what
makes it a huge part of our project is the way it links the parts in our schematic directly to
suppliers order codes. This simplifies and speeds up the ordering process and even
allows you to order them directly from the Eagle program.
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For the actual development process, we developed a schematic for each phase of the
power monitoring system. We needed a current measuring circuit, a voltage measuring
circuit and a circuit to step down the power supply from 120 Volts to 3.3 Volts without
losing any of the critical consumption details. The pictures below show both the current
and the voltage circuit gave us the calculations we predicted based upon the different
load pulls from different devices.
6.0 Project Prototype Testing
6.1 Hardware Methods of Testing
The circuits were tested in the Sr. Design Lab at UCF. The Idea was to take 120VAC
and convert it to 3.3VDC with the power circuit and then use that to power the current
circuit and voltage circuit.
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Figure 6.1.1&2 Outputs for the Power Source and Current Front ends.
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Figure 6.1.3 Output for the Voltage Front end
To test the Bluetooth connection, Realterm was used in conjunction to Code Composer
Studio to read the serial input/output while the Wall Device was constantly streaming its
channel. Connecting was difficult but the results are undeniable: Signal is being sent to
the main hub and they are the correct values.
Figure 6.1.4 Real Term Read in signal
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6.1.1 Testing the MSP430 Microcontrollers
Development and testing will begin on the MSP430 microcontrollers, these devices are the ones running the show, ensuring that these two devices properly perform their intended functions will help the entire project run smoothly. TI offers development and testing boards to accompany their ICs to allow fast market deployment. This is good news for us because the resources provided will help us get to graduation quickly. These development kits offer on board, real-time programming of the microcontrollers on the associated software. The Embedded workbench that fully supports all MSP Embedded processes and implements TI Software libraries. Additionally we are able to choose which programming language we would like to use, including C/ C++.
The MSP430 family features JTAG interface Architecture IEEE Testing Standard 1149.1. The testing standard consists of a group of design rules implemented on the IC level that allow software greater control over the circuit. The JTAG interface was created to hinder the expensive hardware updates that were required to fix the faulty manufacturing of pins that were needed for testing. –primary benefit of the standard is its ability to transform extremely difficult printed circuit board testing problems that could be attacked with on board testing methods into well-structured problems that software can easily and swiftly deal with (Amontec).
The interface between the circuit and software allows for easier debugging of circuit application throughout development and design. Communication between the two devices using JTAG requires a series connection and a shared set of instructions. The host processer (host master) supplies data to the sub meter (slave) through the series connection. The interface calls for two-way communication in order to allow the receiver to respond its results to the host. According to the IEEE standard, each device must be equipped with a base JTAG instruction set in order to properly perform communication requests additionally, the standard provides the opportunity to build upon the standard instructions, allowing the user to customize and implement their own instructions as necessary to their individual project. This provides the opportunity to implement additional testing capabilities, device emulation, and other required device functions (Greenberg). The communication process between these two devices begins in the emulation tool – hardware driven by software – acts as a bridge between software command and hardware. The software translates the programmed orders from the master (host PC) to slave (sub-mcu) the as a series of JTAG commands. From here the JTAG engine pushes these commands to the JTAG interface signals.
In order to conform to the JTAG interface standard as set out by IEEE, a device must contain a Test Access Port Controller (TAP), found directly on the IC and functions as a 16-state finite state machine that generates clock and control
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signals to the instruction and data registers. TAP is where the Boundary Scan Register and other test features of the device are accessed. The only two events that can trigger a change of the controller state are a test clock rising edge and a system power up. The TAP acts as the gate keeper for communication protocols going through the JTAG wires, incoming signals are identified and given a control signal based on the slave Boundary Scan logic.
The JTAG interface also requires four pins with specified testing functions which include:
1. Test Data Input (TDI): It is used to shift data and instruction tests into the Boundary Scan register.
2. Test Data Output (TDO): this pin provides data from the Boundary Scan register or other internal register.
3. Test Clock (TCK): this input controls test-logic timing independent of clocks that normal system operations employ. The TDI shifts values into the appropriate register on the rising edge of TCK.
4. Test-Mode Select (TMS): this input, which also clocks through on the rising-edge of TCK, determines the state of the TAP controller.
TI was among first customers of the JTAG interface, implementing it on the MSP430 immediately after it was released. This protocol is useful for the MSP430 because it allows communication between partner developer tools for the board as well as opportunities for testing throughout the development process. This communication protocol directly impacts the outcome of our project. It is important that we choose a development board that will provide the necessary tools to allow us to easily and quickly program our microcontroller. Furthermore, it is absolutely imperative that the development board be able to communicate with the mcu. The development board will allow us to program the board using software and then transfer this data to the sub meter. Without this communication bridge created by the JTAG interface, countless hours would be wasted trying to connect microscopic pins on a tiny board. The second opportunity that this protocol has implemented to make our lives easier is the ability to test the functionality of the sub-meter mcu throughout the development process. Periodic testing will be helpful to us throughout the development process, in order to ensure that our program is running efficiently on the sub mcu board and to debug any problems that we might encounter.
6.1.2 Spy Bi-Ware (2-Wire JTAG) protocol
TI developed protocol to address the needs of a simple interface that is easy to implement, stays within existing MSP430 design instructions and uses the minimum amount of required communication interconnects between devices. The emulator hardware/software tool that is already found on the board translates and reduces the 4 wire JTAG instructions down to two wires. The Spy-Bi-Wire interface then interprets the JTAG commands and sends them to their intended registers. In essence, the Spy-Bi-Wire has all of the same benefits
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of the JTAG communication conditions reduced to two signals – the SBTCK, clock signal and the SBWTDIO, data input output signal – other wise called a serial to parallel converter. The spy-bi-wire accomplishes this through time division multiplexing, converting the serialized JTAG commands into parallel JTAG commands which can be interpreted by the TAP controller found on the target device.
The Spy-Bi-Wire could prove to be a useful addition to the MSP430 device as it was implemented in order to minimize the overhead of the four-wire JTAG interface for the purpose of testing and debugging the target board’s emulation environment with the assistance of software via the development board.
6.1.3 The Integrated Development Environment
Development kits are suited to be programmed in IAR Embedded Workbench® - an Integrated Development Environment (IDE) that functions as a compiler and debugger tool and supports C/C++ and assembly languages for the purpose of programming 8-, 16-, and 32-bit microcontrollers (IAR). The accompanying software to the MSP430 microcontroller has a code size limit for all compiler, debugger and simulation instructions that caps at 4 Kbytes – due to the basic knowledge of programming that the group collectively shares, it is unlikely that we will exceed this limitation. Both TI and the IAR Embedded Workbench companies provide support and resources for coding and debugging microcontrollers within the Integrated Development Environment. Furthermore, TI offers multiple tools – such as C-SPY debugger with MSP430 simulator and example project tutorials and code templates – within the IDE to stimulate the early stages of development for multiple MSP applications.
In order to obtain precise energy consumption measurements and perform necessary power calculations the MCU must have a powerful library that can calculate complex energy equations like those presented in TI’s introduction to the MSP430 Sub-Metering application technical document (Dhond), featured in Figure 6.1.3.
The MCU Energy Library provides easy implementation for power measurements and calculations on the MSP430AFE2xx. Furthermore, being able to program directly on chip allows flexibility in carrying out instructions. Allowing user input
to control what functions they require of the MCU.
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The wide variety of tools available for beginners through TI and the MSP430 make it the most attractive microcontroller on the market for our project. Not only will this assist three electrical engineers build upon our basic knowledge of coding microcontrollers, it will also provide tutorials for us to set up our microcontroller for energy related applications, the area we will be most concerned with in terms of accuracy of measurements and calculations.
Figure 6.1.3 – These are typical power functions that the MSP430’s energy library must be able to calculate Courtesy of Texas Instruments Pending Permission
6.1.4 The MSP430AFE Target board
A standalone ZIF socket target board is used to program debug the MSP430 through JTAG or Spy Bi-Ware (2-wire JTAG) protocol. The development board supports all MSP430AFE2xx Flash parts in a 24-pin TSSOP package (Texas Instruments). The development board comes with an LED indicator a JTAG adapter and header pin-out for prototyping. The Figure 6.1.4 below shows the PCB of the Target board and points out the various communication interfaces on the board for testing. These are the various pins that we can connect to in order to being developing.
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Figure 6.1.4 MSP-TS430PW24 Target Socket Module, PCB
Courtesy of Texas Instruments Pending Permission
The first test of the MSP430AFE2xx will be to ensure that the microcontroller properly calculates power equations such as those derived in Figure 6.1.3. Once proper and accurate calculations are proven and tested we can begin testing the communication protocols between the two microcontrollers.
6.1.5 Testing and Debugging the MSP430F6638
The MSP430F6638 features the MSP430 USB Debugging interface as a development tool. This flash emulation tool is designed to allow for immediate development on the MSP430 MCU. It includes USB debugging interface used to program and debug the MSP430 in-system through the JTAG interface or the pin saving Spy Bi-Wire (2-wire JTAG) protocol. The ultra-low power of the flash device requires no external power supply. The MSP-FET430UIF development tools supports development with all MSP430 flash devices. The USB interface physically connects both the microcontroller and PC side microcontroller to the computer where the integrated software environment, the IAR Embedded Workbench Kickstart for MSP430, allows for real-time programming. While in the development stage introductory code is offered to help the user get started and understand the testing and debugging phase of the MSP430. The flash emulation tool is another tool meant for easy communication with MSP430 target devices as the device is fluent in the JTAG interface communication protocols in addition to target boards that support the Spy-Bi-Ware debug protocols.
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6.1.6 Bluetooth Testing and Evaluation
Figure 6.1.6 Transmission Values for CC2541 Matched to a 50 Ohm Antenna Courtesy of Texas Instruments
Using the CC2541 development kit, we will test and configure our devices for use with MSP430AFE253 and MSP430F6638. Before configuration can be done, development of the circuit must be done. There is no material provided from Texas Instruments on the MSP430AFE253 being directly connected to a Bluetooth device so at this point we are uncertain how our prototype will act with the amount of memory provided as the device is usually coupled with a host MCU with a significant size. All connections are provided for UART/USART and it seems possible to make these connections between the two devices. In the implementation document the primary MCU, the MSP430F6638 is used to run LCD functions and also handles wireless communication functions to and from the MSP430AFE253 (Texas Instruments).
The first thing to overcome in hardware trouble shooting for the prototype, is ensuring that the antenna is matched correctly to the CC2541. The balun, which will possibly be acquired from Murata if matching becomes a problem, must be matched to 50 Ohms. When the line is matched we will check it for power output and make sure we have achieved typical levels as listed on the datasheet for CC2541 using the development kit for the CC2541. Figure 5.2.3 shows the Evaluation module schematic for the CC2541. This will primarily be used to get a jump start on how to implement the circuit into our design. Details for transmission power are included in Figure 6.1.6. These are the values we want to achieve with our RF ports matched to a 50 Ohm antenna (Texas Instruments).
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Figure 6.1.6-1 Typical Receiving Characteristics For CC2541 Courtesy of Texas Instruments
After testing is finished on the connection from the CC2541 to the antenna, the process will be repeated for another antenna to ensure we have connections between two active wireless devices. We must also ensure that one device is acting as a master for all the other devices to connect to. This will need to be configured using the CC2541 development kit and tested for appropriate power output. Figure 6.1.7 displays typical values for the power output from the CC2541 acting in Bluetooth low energy mode. We want to be able to match these values to allow the best connection between devices.
With connections appropriately configured, data transfer will be tested between the wall units MSP430AFE253 device and the MSP430F6638 MCU in the main hub. The devices should be connected by standard wire to the correct I/O ports and correctly using UART communication. The ports and registers will be checked for the test data sent from the MSP430AFE253 to the MSP430F6638 development kits software suites. This will allow us to see if the data was sent correctly without error between the devices.
The final task will be applying these prototyping setups to the final device layout in a compact package and making sure there is no complications with the final PCB layout function.
6.1.7 SiteplayerTM Testing and Evaluation The Siteplayer SP1 module is what will power our web based page and app operation through a convenient on device web server. Programming it to function with the MSP430F6638 will not be a hard task as it can act as a standalone device with its own hardware. Figure 6.1.7 depicts the typical application of the Siteplayer module in a circuit.
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Figure 6.1.7 Schematic of SiteplayerTM Application. Reprinted with Permission (Pending) from NetMedia.
The Siteplayer SP1 is the last piece of hardware we must test and evaluate for the design. We will first ensure the SP1 is connected properly and all essential electronics are working correctly. The device should be connected as well to the already functioning and stable MSPF6638 interfaced with the Bluetooth device.
Between the Bluetooth connections we should be receiving test packets of data to ensure a stable wireless connection. The web page data and anything that will be hosted on the server should be already programmed onto the device and tested using the SP1-K development kit. The data will be programmed in the language of the groups choosing discussed in the software portion of this report. After the SP1 programming, the module will be tied to the MSP430F6638 using the UART/USART lines. We will be testing for accurate data transfer between the two devices sending test packets to make sure the devices are sending and receiving the same data. The Ethernet connection should as well be configured at this point and have been tested using the SP1-K , making sure the web data was able to be streamed and accessed. There should be no metered data when this occurs but a fully programmed web page should be accessible from this data.
This being the last device to be tested and checked for accurate data and electronic signals, we will be ready to move onto finalizing our design plans and setting up schematics for the final product.
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6.2 Siteplayer Programming Overview For the most part the below section is just to show our original idea of how the main hub handoff was supposed to work. Siteplayer is one of those really great devices that worked really well but only for one program and only back in the early 2000’s. All project information on it refers to it taking data and posting it online with smooth design. But the code for it is ancient and narrowly worded so it can’t be extrapolated to different situations or functions. So while the next section is important because it led to the final result, it didn’t end up getting used.
6.2.1 Overview
Acclaimed as the world’s smallest ethernet web server, Siteplayer is a little bit of everything rolled into one. Siteplayer is a microprocessor’s best friend as when you plug it into a microprocessor-based device, it immidiately becomes web enabled and a whole new range of possibilities open to it. The SitePlayer is a relatively inexpensive way of reaching this result compared to the rest of the its family of software servers. A key feature of the SitePlayer is that it handles most of the protocals and packets separate from the device processor which is very important for security reasons. Because the Siteplayer needs the device’s processor it is technically a web server coprocessor, and it is a good thing that it does things based off the processor because that means the processor doesn’t have to speed up or be affected in any way in order to link together. A two wire serial port appears to be the only thing that is needed to have the SitePlayer and the device communicate. It is an object communication and no network code or TCP/IP is required. While the SitePlayer has a minor “stand alone” mode, this is not necissarily important to us as it is not used. SiteObjects however are very imortant for they will lay the foundation for the software aspect of our device. SiteObjects are the non-programmer’s dream as it allows you to create an interface without resorting to Java or CGI or some other form of higher level language tool. Any standard web tool used for authorizing can be used to make the pages for our device. We are just going to link an eclipse environment document to it since most of our programming in in Java. The Siteplayer actually takes in the web pages into its flash so it can work with it properly.
6.2.2 Creating a Project
Several steps must be completed before using the siteplayer. A Project file has to be created so the directions for the siteplayer can be defined. This document will state how to perform and assembled using SiteLinker whose sole purpose is to link your site to the SitePlayer. Once connected to the internet with an Ethernet cord, information can pass to, not just from, the SitePlayer. Four steps of setting up a definition file include:
1. Using a .SPD file (SitePlayer Definition File) objects must be defined and created that will help to organize your site.
2. Web site documents must be created in any HTML editor
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3. SitePlayer has a .SBD file (Binary File) that needs to be downloaded and assembled via the SiteLinker program
4. Finally, when all that is completed, SitePlayer can be Surfed
6.2.3 Data Flow
6.2.3 SitePlayer Data Flow Chart Beneath is Figure 6.2.3, of how the data flow works for the SitePlayer. Once the chip is plugged into the processsor we have, we can take the information from this device and run it through a SiteObject and eventually an HTML buffer and make a easy device that displays exactly what we want. The information that the controller passes to the Siteplayer is stored in Object defined memory locations through the serial port. These Objects are written and defined by the Definition file. On reqeust by the site/web pages, the Object values that are stored to memory are substituded in through the Ethernet Cord.
6.2.4 Definition File The definition file is limited only by the programmer’s imagination. It is linked with the SiteLinker to bring out any number of outcomes. Once the SitePlayer Definition file comes in and tells it what to do the SiteLinker creates the SitePlayer Binary image file to get downloaded to the SitePlayer. This .SPB contains startup parameters which for us will be the Usernames and acounts for each current account along with any other user information that needs to be uploaded. It also includes the usable web pages and SiteObjects that have already been designed. The Definition File works off its own branch of assembly language that is sometimes referred to as SiteLanguage. The language is broken into the Definition section, Object section and Export section. The comments section, the fourth section, is generally separated by semicolons.
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6.2.5 Definition Section
The Definition section is easily isolated as each definition is preceded by dollar signs ($). This document, unlike other languages, is space sensitive. There are several very important commands that should be briefly covered: $DHCP defines whether SitePlayer needs to keep a fixed IP address or if it collects one from a DHCP server. Ours will be on until that solves problems so there will not be an issue with generating specific addresses for each of our devices. $Devicename can assign up to 64 characters. Ours will be SCHNAPS for simplicity. $Include is big because it allows us to connect our library of objects from our Java (Eclipse Specifically) environment. $Parse allows several different types of files to be searched for including htm, html, xml, and wml files. Since there are several very important jar files in the Eclipse environment that allow it to attach everything together, this will be used unless the program is fine with working with Eclipse at as an endpoint as opposed to collaboratively. $PostIRQ is a function that lets buttons be pressed on the SitePlayer and used in its design. This means two things. First is that we are able to include an on/off switch on our device that enables and disables the Blackout Relief Program we are going to have. Losing power at random times would cause many issues if the Relief program couldn’t be turned off. This way, when somene wants to relocate a device, they can turn it off and not have relief on its way imminently. $Sitepath is used as a backup URL for your device. While it will be looking for the correct address, INDEX.HTM will be loaded if no filename is specified.
6.2.6 Object Section
The Object section which is a very important section. It typically is made up of our specific variables and their sizes, types and initial values and these variables become the SiteObjects. Its importatant that the SiteObject’s names we issue here are the same ones from the HTML files and device processor or they will throw errors and will not work. Limit name length is 32. It is interesting to note that the SitePlayer doesn’t have to be directed by another device but can actually direct a different device. If a Display is plugged into the COM port then you can actually have it display certain messages just by pushing buttons on it. Unfortunately, this option is not quite complex enough for what we are trying to accomplish and we need more than to just have a device say ‘hello’ when the hello button is pushed. The Baud Rate is a statistic that needs to be calculated for proper connection to the site. Once calculated, the Baud Object can be created. The HalfSec object 0FF1Fh is a natural build in clock that the SitePlayer provides. Basically, this is an object that decrements every .50135 of a second and can easily be build to provide easy math equations to help with our charts or graphs. The ExitIf0 modifier is going to allow us to initiate some extra security to
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the website and user information. What this object does is that it cancels any displaying or loading of the website if what is in that register is zero. Now combine that with a login que logic sequence and now people can’t just plug in the website that leads to someone else’s account without logging in properly with the proper password. When combined with the halfsec object and a little more programming logic, it can easily put a counter on each person logging in so they don’t just leave their application on and steal bandwidth without actually using the information provided. $OutputOnly is a fun command that keeps the user from changing data on certain pages. This seems especially important on the history page as once the data is changed then it becomes increasingly difficult to recreate that data. $Bidirectional is a command that could be put in front of an object presented to the energy company. When duke has to change the stages and duration of power outages it makes sense that they need to be able to alter the data. Just not necessarily all of it.
6.2.7 Export Section
The export section provides a means to export files to our compiler by defining how and where the information needs to be sent. It can also me made to create web pages when configured correctly. Different file exports need their own function and location/file format.
6.2.8 Web Page Files
Java and Visual Basic Scripting are very good tools for providing the live updates of data for the website but the SitePlayer doesn’t require them for development. We will be using Eclipse to develop the look and layout of the pages which will be the interface of the device through SitePlayer.
6.2.9 SiteObjects
The SiteObjects will come in and bolster the Java code with its power and flexibility. There is a way to connect the SitePlayerPC to view and test pages without applying the processor device. First, a standard web site must be built. Ours using Eclipse for its broad application content and Object Oriented Programming. And then simply change the the HTML code to point at different objects within its own data. Using the .SPI (SitePlayer Interface file can be used to add control. Once the HTML file is created, the actual data in it can be made up entirely of objects directly from the SitePlayer. Objects consist of variables of data with a specific size, type and initial value. They should be defined in the Definition file. Using an object is typically done by signalling with an arrow (“^”) key and then the name of the object, optional modifiers and any special commands. Modifiers are used to accurately allow certain manipulations of objects using SitePlayer while it is emitting data. When using modifiers, the
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actual HTML is not being changed, only the object. Some modifier objectives include selecting particular digits within an object, doing simple math to subjects, or choosing a specific bit within an object. Some issues arise based off the logical arrangement of text and objects being laid next to each other. Sometimes a double carrot must be used when dealing with filenames when division is not wanted.
6.3.0 Web Pages
While not especially needed, SitePlayer provides a good range of HTML files and graphic controls to help get someone started on their website and make sure it is attractive, active and professional. The main root to the SitePlayer chip is read from the $Sitepath definition when the site is eventually assembled with SiteLinker. For SitePlayer, the Interface file is what provides the ability for recieving data from the web browser. While it doesn’t matter what name we pick, interface.spi creates the smallest amount of confusion. It can be used to adjust and look up SitePlayer object names and values when placed into hyperlinks. It can also be used to get submissions when given the form action file name or it can redirect and reroute the browser or submit to it once it has linked with the correct HTML instructions. It is a good thing that HTML pages are small otherwise they would not fit into SitePlayer’s miniscule 48K limit (for web pages). What we have planned should just barely fit into that capacity. In order to make the interface file, the spi file needs to contain the next web page location after the setpoint had been changed. The browser will go to the page, get the information and then come straight back to its original page with updated information. An extra line at the end of the file opens up the scheme and allows it to write in its routing information. A different way to do the job of the interface file is through navigation links. Formatting a link to send specific information that is requested. SitePlayer doesn’t use HTML convention for getting its information. This is rectified by changing the POST tag to a GET tag in an HTML <FORM> tag. A few things to note when dealing with the different means of information interaction include that Check Boxes only send information when clicked and send nothing when unclicked. This could be problematic if a user wants an unclicked box to mean something. This is solved by adding a hidden field that sends a zero when Check Boxes are unchecked. Since the SitePlayer receives things in order and overwrites previous values as new ones come in, it’s important to keep your hidden zeros coming in first such that the one can overwrite it if a box is checked. In a radio button, a hidden field isn’t necessary. Binary values come out very easily and a ‘#’ or ‘$’ allow other values to be printed as well. List/Menus always submit some value. Unfortunately, if no value is selected, the List submits the first option on the list. SiteObjects have to be used to prevent a change from occuring when nothing is selected. We will define the top item in the list to be the current item and that will solve that issue. Remember that a great aspect of SitePlayer is that as long as the format of the data it receives is proper, it doesn’t care how it gets the information.
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6.3.1 Binary File
Figure 6.3.1 SitePlayer Editor
We have briefly talked about the Binary image that gets defined by the Siteplayer Definition file and told exactly what to do through the code. Well once written, this is downloaded to SitePlayer through a stalwart Ethernet connection and it can then interact with the device and serve up the web pages. SiteLinker is a primary tool in that assembling and downloading process. In fact, this is SiteLinker’s main role in the grand scheme. SiteLinker has very specific instructions, however, on how to be set up properly:
1. A SitePlayer Definition file or an older SitePlayer Binary file need to be opened on the File menu of the SiteLinker Program.
2. SiteLinker’s password and IP address needs to be configured to the same as the SitePlayer’s throught the Configuration Menu.
3. Definition files use a different command to compile as old Binary files but either mode must be selected from the Download Menu SitePlayer also has a Browser menu for accessing your primary browser, a Calculator, and an Editor menu for changes that need to be made to a definition file. Beneath is Figure 6.3.1 of what the editor window looks like.
6.3.2 Surf SitePlayer
Now that the Binary image has been created, downloaded, defined and assembled, it is possible to surf the SitePlayer if the web browser is pointed to
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the correct IP address (SitePlayer’s IP address). Since the Browser is the inferface interface to the SitePlayer, after the correct changes and tweaks are made, there should be no issue communicating with SitePlayer through a default browser. There is a setting that keeps the cache from cleaning itself and helps with speed as the pages become easily accessible. Disabling a proxy server helps some as well. What hasn’t been talked about much is SitePlayerPC. It’s main purpose is to emulate the Siteplayer chip without internet connectivity. This enables a testing realm that is much more simple. You also don’t have to enable the chip to take instructions from the device processor. You can plug in initial conditions and play around with everything with just the SitePlayerPC and simulate what results will occur. Large projects like ours will use this feature extensively for component and comprehensive testing.
1. Run the SitePlayerPC program. Open a Binary file with the File Menu. With that running the SitPlayerPC server with activate.
2. COM Port configuration will designate what events will occur to link certain devices to SitPlayerPC. No devices mean the setting should be set off for the COM Port.
3. Use the Broswer and SitePlayer site to interact with SitePlayer. Testing and changes are available to be seen once the binary image is Reloaded.
SitePlayer doesn’t play well with other servers so they must be disabled before SitePlayerPC is running. An ethernet network card is required to be downloaded to the computer and for development there could be a need for multiple development cards to minimize traffic and keep speed from dipping. To develop a SitePlayer’s webpages, the IP address has to be plugged into an $InitialIP function or, in our case, the $DHCP is on. This means that the Serial Port Tester is can be used to discover the IP address even after the it has been reassigned by the DHCP.
6.3.3 Serial transmitting and Receiving
There are two different ways to get an object to the SitePlayer. The first and easiest is by using the serial port but if the device doesn’t have a serial port then the SitePlayer can be ‘bit banged’ through a pin on the device exterior. The code for that is relatively small and only requires 128 bytes. Without a serial port the information doubles. The easiest way to fry a SitePlay is to use the serial port I/O while it is downloading new firmware or web pages from the Ethernet jack. If this is undesirable, then there should be some sort of coordination between the two and it generally is ideal to unplug one while changes are going through the other. The bit values of a command byte are split into two different subsections of Command Value and Number bytes. Each subsection is split into 4 sections of one bit. The top bit is set each time form data is sent to the SitePlayer device. This happens whether a change occurred or not. This brings up ComParams which set the baud rate and even the response delay. It standardizes the baud rate when it is reset and even controls the maximum delay. If changes need to be made to either then the ComParams must be edited. The best way to send things to the SitePlayer from the device is by using Write or WriteX commands. The
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best way to send objects from the SitePlayer to the device is the Read or ReadX command. To send an object from the device strait to memeory the UDPsend command is the the best option to use. It provides a certain level of flexibility to have this command.
6.3.4 Bit Variables
SitePlay has a lot of bits hardwired into it to help it get around having to calculate where a bit is located. These are called bit variables. If it has to go around a variable to change a device bit, it doesnt have to modify the byte in a different area and transport it back and forth. To avoid error, Siteplayer runs the read, modify, and write operations for you without interrupts. This way, there isn’t any chance for the device to write back while it is running. SiteLinker is in charge of allocating several physical bits in the memory for bit objects. Only when the memory is not used is it allowed to be used for regular objects. While these commands are used the same way as before commands (Read, Write, etc) the second byte controls what information is sent. Toggle bit is a command that takes a byte in as an arguement as well as a specified address byte and flips the bit at that specified address. An issue that will need to be worked around is that only 16 bits can be allocated per command to write or to read. An easy way to get around this is with multiple single byte objects. These can be sent much faster with a multi-object command than the lengthier commands.
6.3.5 Serial Port
There is an easy way to test the serial port called the Serial Port Test Program. It’s also called the SitePlayerSerialDemo.exe and it is included in all SitePlayer software. If SitePlayer is unavailable through ethernet then this is a way to set the IP address or to change your PC COM port to match SitePlayer’s. The process goes as follows:
1. Connect the SitePlayer Dev Board Serial Port J9 to one end of the serial cable
2. The other end goes to the PC’s serial port
3. Once physically connected the option to start the SitePlayer Serial Port Tester program should appear and needs to be activated
4. Select from the Comm Menu the PC COM port
6.4 Software Testing
6.4.1 Functionality Testing
Check all the links: This step is primarily for external links. The site must have a functioning URL to get to it but also any external links must lead away fluently and accurately.
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Test forms in all pages: Most important when logging in. Making sure alternate accounts are not visible to multiple users and the correct accounts are being pulled up with the right username.
Cookies testing:Cookies need to help reduce login time upon repetitive relogs yet cannot compromise the security of the site as a whole
Validate your HTML/CSS: If code is not optimized for Search Engines then it will be a missed opportunity for marketing. Validate by running code through http://validator.w3.org/.
Database testing: Database testing is a large part of this project as the overall goal isn’t reachable without server/applet communication being on point.
6.4.2 Usability Testing
Test for navigation:Make sure that the navigation from one part to another function’s properly. If the Contacts page doesn’t take you to the contacts page then there is a problem.
Content checking: Includes spelling and grammar tests along with having a style and color scheme that doesn’t clash or pry the user’s attention away from the important content of the site.
Other user information for user help: Since our site is not very long winded or extensive so a search bar isn’t going to be all that important but contact information will be provided.
6.4.3 Interface Testing
There are two main interfaces: The Web server and application interface and the Application and Database server interface
6.4.4 Compatibility Testing
Browser compatibility: Google Chrome, Explorer, Safari etc. different Browsers sometimes show things differently. Web site must be tested on each platform and stylized to work properly regardless of which browser is being used
OS compatibility: Generally the more popular API’s are available on all OS platforms. However, there are many API’s that are not. Testing on an apple and a Windows computer must be included in testing
Mobile browsing: Mobile browsing will not be as important for our site because the app will be available and should have most of the functionality of the site
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Printing options: Fonts, page graphics, page alignment. Everything just needs to look right when it comes out
6.4.5 Performance Testing
Web load testing: Delivering to multiple computers at the same time is sometimes difficult to test on our budget and resources. In this case a series of four computers with multiple browsers and windows open and using the site at the same time should be adequate to test the adequacy of the load potential
Stress testing: The website will be forced to break at some point in time. It could be something small like a wrong input for a password. Or it could be something more serious like the server sending it too much information at the same time. This test is generally going to make sure that the site responds correctly to these issues: Initial tries it should restart and as for a relog but if extensive errors occur repetitively then notifications should be sent out.
6.4.6 Security Testing
Internal pages shouldn’t be accessible unless a password has been entered. Plug in an internal URL and see if the actual page comes up or if you are rerouted to a different page.
The extended url should include a number for what account is being displayed. If that number is changed, a new account should not be displayed without asking for username and password
7.0 Administrative Content
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7.1 Milestone Discussion
Figure 7.1 Milestone Timeline
Setbacks and miscalculations will define the timeline for the spring. However, if neither of these things happen then we will be done without project a month early. For the spring timeline it is easiest to just define each portion of the spring by what tasks are parallelizable. The website and ordering parts will begin as soon as January starts. 2 months are allotted for general website design and approximately 1 month for the first stint of part ordering and assembly of the plug in device and smart meter. Ordering the parts and website assembly can be done at the same time while assembly of the two main physical components can be done shortly after the parts arrive. The app assembly could be done at the same time as the website assembly, however, two reasons have us push it back to a late February start: the first is manpower, in a three man team there are just so many things we can do at one time and the second is that it is more of a second tier deliverable in the overall goal of the project. So it is decided that once the website is done then the app can be worked on. With basic assembly done, component testing can begin. Each subpart needs to be working properly before it begins to work with other parts of the module. As testing comes to a close then the devices need to start communicating with each other. And once the plug in device and the smart meter and the website all seem to work together, then comprehensive testing and preparation for presentations begin.
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7.2 Budget and Finance Discussion The group has compiled a list of parts and kits that will be used to construct a prototype and carry us to the final design. The list of items is an estimate of what it will cost to get the prototype started and how much we expect it to cost. We expect to start ordering as soon as possible to being collecting data for the prototype. We will be receiving funding from an outside source. Duke Energy has approved our proposed budget for $809 dollars for development of devices that contribute to sustainability. This proposed list of items that we submitted to Duke has been vastly changed and a better estimate of the budget has been drawn. Table7.2 shows the updated list of items. These prices have been estimated and rounded to the nearest dollar amount.
Item Purchased From
Cost Units Total
MSP430AFE253
Development Kit
Texas Instruments
$175 1 $175
MSP430AFE253 Digikey $6 8 $48
MSP430F6638
Development Kit
Texas Instruments
$89 1 $89
MSP430F6638 Digikey $11 2 $22
CC2541
Development Kit
Texas Instruments
$99 1 $99
CC2541 Digikey $7 9 $63
Siteplayer Development Kit
NetMedia $80 1 $80
Siteplayer SP1
Module
NetMedia $25 2 $50
PCB BatchPCB $40 6 $240
Housing Various $30 6 $180
Table 7.2 Estimated Budget Total = $1046
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Many values were rounded generously up to account for parts that were not included in Table 7.2 such as discrete components. Discrete Components have little effect on the amount we need to set aside for the budget.
8.0 Project Summary
It is clearer now more than ever that the energy infrastructure in this country is rapidly changing. Advancing technologies are pushing communication of all types of data and the electricity and the grid are no different. Utility companies need the ability to communicate with the consumer (through their meter) to pull dynamic information about energy usage. While on the consumer end, in order to take control of their energy consumption, they must be able to communicate with the energy consuming devices in their homes in order to manage the places that could use the most improvement.
In order to create the incentive for the consumer to change their usage habits the most important features we were looking for in this project include, easy installation, the ability to wirelessly communicate data efficiently and accurately, and the capability to access this information conveniently.
With three electrical engineers on the team and no computer science/engineer types, as a team we had to decide exactly the amount of programming we could handle to complete the project efficiently. Now a days semesters pass within the blink of an eye and we have no time to waste dilly-dallying around trying to learn new coding languages or figuring out how to set up our own internet protocols.
For this reason alone TI was an obvious choice for microcontrollers because of all the support and resources they offer for programming their MSP430s including their very own Wiki page, a forum that hosts both consumers and TI employees for the exchange of ideas and dozens of developing, testing and evaluation tools.
Furthermore, TI has made it energy metering a core technology in amongst their vast range of products. This company recognized the future need for devices that would require energy and power measuring capabilities in addition to offering the availability to incorporate wireless communication protocols. TI has laid a down the foundation for countless numbers of energy efficient tools that will not only help consumers save money by wasting less energy, but also save the grid infrastructure from wasteful consumers. The various development and testing kits that TI provides enable quick path to market. This is a driving factor behind choosing TI for our AFE devices. An MSP430AFE2xx chip combines the ∑-∆ ADC measurement devices and the calculating processing power of a microcontroller to create an incredibly efficient tool for monitoring energy consumption. This device has the capability to wirelessly communicate data, which allows it to perfectly integrate into the average consumer’s everyday routine.
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In order to save ourselves the headache of trying to create an internet protocol for a server to house the collected energy data, our team opted to invest in the NetMedia SitePlayer. This device by passes the coding required to create the protocol, so all you have to do to get your information to a server is connect it to the SitePlayer. We all feel that this is the right choice for our team because it will allow us to focus on our individual objective without worrying that there won’t be a way to view all of our hard work (all measurements will be available online, with the assistance of the Siteplayer server).
Appendix A: Copyright Permissions
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Appendix B: Bibliography
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Texas Instruments. MSP430AFE2x3: Mixed Signal Microcontroller . Datasheet. Dallas: Texas Instruments, 2011. Document.
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Wium, Espen. Design Note DN041: Using CC253X or CC254X with Dipole PCB Antennas. Design Report. Dallas: Texas Instruments, 2013. Document.
