Stand-Alone and Stand-Alone and Mesh Networks of Mesh Networks of Dissolved Oxygen Dissolved Oxygen

(DO) Monitors(DO) MonitorsSd-May11-20Sd-May11-20Betty NguyenBetty NguyenScott MertzScott Mertz

David HansenDavid HansenAshley Ashley

PolkinghornPolkinghorn

AdvisorsAdvisorsJoseph ShinarJoseph ShinarRuth ShinarRuth Shinar

withwithBob MayerBob MayerAlex SmithAlex Smith

BackgroundBackground

ApplicationsApplications Waste water treatmentWaste water treatment Chemical plantsChemical plants Fish farmsFish farms Fermentation labFermentation lab Monitoring water qualityMonitoring water quality

Saves energySaves energy

Market Research

Existing solutions: > $1000 HACH LDO Process Dissolved Oxygen

Probe $1565 No remote capabilities Market: over 100 M

Project ObjectiveProject Objective

Existing monitors and networkExisting monitors and network Account for temperature variationAccount for temperature variation

Temperature sensorTemperature sensor DO level calculation modificationDO level calculation modification

Ensure functioning mesh networkEnsure functioning mesh network Test integrated unitsTest integrated units Make necessary changesMake necessary changes Add new functionalityAdd new functionality

Conceptual SketchConceptual Sketch

Functional Requirements Required

The monitor units shall take readings of dissolved oxygen. The monitor units shall wirelessly transmit their readings to the

master controller. The master controller shall request readings from each monitor

unit. The master controller should have a graphical user interface to

display measurements. The master controller user interface shall allow the user to poll a

monitor unit for data. The system shall query each monitor unit for data through the

master controller. The Windows service shall log all data processed through the

unit in a SQL database. The network nodes shall create a star-like topology

Optional The network nodes shall create mesh network topology The master controller shall send calibration data to each monitor

unit.

Non-functional Requirements

The system shall have an optimal operating range of 1000 meters.

The microcontroller shall enter a sleep state between samples.

A temperature probe shall be attached to the existing sensor probe to increase calculated accuracy.

Constraints Operating temperature: 0 to 50° Celsius.

The temperature sensor must be accurate to ±1°C to satisfy this constraint. DO Monitor units need to be resistant to changes in temperature.

Operating environment: water resistant. The probe should be resistant to water damage.

Battery power is limited in sensor locations. The system needs to conserve as much power as possible when not measuring DO levels to ensure long battery life.

Existing implementation uses Zigbee. Zigbee modules cannot route while in sleep mode.

Risks

Circuit board redesign Encountering circuit issues frequently

Existing design problems Sleep prevents mesh network from

functioning Power is controlled by DO Monitor, not

ZigBee node

Functional Decomposition

DO MonitorDO Monitor

Zigbee NodeZigbee Node

Hardware Platforms

AtxMega128 ZigBit Amp Custom DO Sensor Temperature Sensor: Temperature-

to-Voltage TC1047

Test Plan: DO Sensor Temperature sensor

Verify voltage levels from temperature sensor.

Verify ADC conversion. Verify temperature constraint extremes.

DO Sensor Verify DO sensor readings at room

temperature. Verify DO sensor readings at various

temperatures. Verify device enters and exits sleep mode

Test Plan: ZigBee Node

Verify the ability of a ZigBee Node to receive a message.

Verify the ability of a ZigBee Node to transmit a message.

Test Plan: NW Coordinator; Master Controller

Network Coordinator Verify the ability of a Network

Coordinator to receive a message. Verify the ability of a Network

Coordinator to transmit a message. Master Controller

Verify the ability of the Master Controller to send a command.

Test Plan: Integration Testing

Verify communication between the Master Controller (PC) and Network Coordinator.

Verify transmission of a command from the Network Coordinator to all ZigBee Nodes by verifying that the same command is read on all ZigBee Nodes. This is part of the star topology.

Verify transmission of data from any ZigBee Node to the Network Coordinator by verifying the same data was received by the Network Coordinator. This is also a part of the star topology.

[Optional] Verify a ZigBee Node is able to receive data from another ZigBee Node and able to pass it to the Network Coordinator. This makes a mesh network.

Repeat steps 1 - 4 with all command types.

Test Plan: System Testing

Verify power usage when in OFF state. Verify the device enters sleep mode when

not in use. Confirm the user interaction of pressing

the “Take Sample Now” button in GUI will result in new measurement data from all DO monitor units.

Confirm the user interaction ability to reconfigure coefficient calibrations on all DO monitor units.

Accomplishments

Temperature sensor tested in hardware

Hardware debugging Obtained necessary software stacks Some network testing Documentation clarified and

expanded

Project Status

Milestone Description  Temperature HW Complete

The temperature sensor will be integrated with the DO Monitor.

X

Design Document Complete

Design document will be completed. X

Temperature SW Complete

Temperature readings should be accurate to ±1°C. DO readings should be adjusted using the coefficients for

the correct temperature range.

 

Mesh Network Functional

The mesh network has been confirmed to be functional, and all errors have been corrected.

 

Sleep Mode functional

The unit has been confirmed to enter sleep mode, and it enters a decreased power use state.

 

Mesh Network Temperature Calibration Expansion complete

New values for temperature coefficients can be sent over the mesh network from the GUI to individual

monitors, and the monitors can replace their coefficient tables.

 

Schedule

Resource Estimate

Name PriceVoltage Regulator

$ 10.00

Diodes $ 6.00

Temperature Probes

$ 6.00

ATXMega $ 40.00

LED Drivers $ 8.00

Digital Supplies $ 10.00

Zigbits $ 100.00

LCD $ 20.00

Other Parts $ 20.00

Total $ 220.00

Member Contributions David Hansen

Extensive hardware critiquing and debugging Scott Mertz

Hardware debugging Temperature sensor testing

Betty Nguyen Network testing Setting up test framework

Ashley Polkinghorn Network testing Setting up test framework

Next Semester…

Building and testing two more boards Make Master Controller consistent

with sleep mode design Possibly implement remote calibration Finish testing network components Finish implementing and testing

temperature firmware Integration testing