LED-Outlined Traffic LED-Outlined Traffic Signs on the ISU CampusSigns on the ISU Campus

Jacob BonnerJacob BonnerDustin NekvindaDustin Nekvinda

Hieu PhamHieu PhamBrian SchnurrBrian SchnurrDavid WallaceDavid Wallace

May 07-01May 07-01

Project OverviewProject Overview The goal of this project is to implement a set of The goal of this project is to implement a set of

diamond shaped pedestrian cross-walk signs that diamond shaped pedestrian cross-walk signs that will stand out and alert drivers to potential dangers. will stand out and alert drivers to potential dangers. The signs will have light emitting diodes (LED’s) that will The signs will have light emitting diodes (LED’s) that will

flash to get the driver’s attention. flash to get the driver’s attention. During class breaks During class breaks On-demand On-demand Override switch Override switch

The signs will communicate with the master system via The signs will communicate with the master system via wireless signal. wireless signal.

The system will also be equipped with countdown timers The system will also be equipped with countdown timers that inform the pedestrians of the time they have remaining that inform the pedestrians of the time they have remaining to cross the street before the sign’s LED’s stop flashing. to cross the street before the sign’s LED’s stop flashing.

The system will be powered by a solar panel/battery back-The system will be powered by a solar panel/battery back-up power source. up power source.

It is the intent of this project to reduce possible It is the intent of this project to reduce possible accidents and violations by alerting the driver to a accidents and violations by alerting the driver to a potentially dangerous situation.potentially dangerous situation.

Intended Users and UsesIntended Users and Uses The system designed in this project is intended to be used The system designed in this project is intended to be used

by Iowa State University Department of Public Safety. The by Iowa State University Department of Public Safety. The system will be set up to operate on its own with minimal system will be set up to operate on its own with minimal interaction necessary. Once implemented, the only interaction necessary. Once implemented, the only interaction with the system shall be when the automatic interaction with the system shall be when the automatic flashing time needs to be changed, or during out-of-session flashing time needs to be changed, or during out-of-session breaks when the over-ride switch will need to be flipped. breaks when the over-ride switch will need to be flipped.

After installation the intended users will include motorists After installation the intended users will include motorists and pedestrians. Pedestrians will rely on the system to and pedestrians. Pedestrians will rely on the system to provide a heightened sense of awareness for the drivers. provide a heightened sense of awareness for the drivers. This is intended to reduce the danger to pedestrians This is intended to reduce the danger to pedestrians crossing campus streets.crossing campus streets.

The intended use of this system is to alert drivers of The intended use of this system is to alert drivers of situations that may involve pedestrians on the roadway. It situations that may involve pedestrians on the roadway. It is designed to allow pedestrians to cross the street safely is designed to allow pedestrians to cross the street safely and tell drivers that there is a heightened chance of and tell drivers that there is a heightened chance of pedestrians in the street. The system will be placed where pedestrians in the street. The system will be placed where there is already a cross-walk, but more attention needs to there is already a cross-walk, but more attention needs to be drawn to it.be drawn to it.

Operating EnvironmentOperating Environment The operating environment will be a recommended The operating environment will be a recommended

location on the Iowa State University campus to be location on the Iowa State University campus to be determined by a CCEE undergraduate course determined by a CCEE undergraduate course taught by Professor Shauna Hallmark. taught by Professor Shauna Hallmark.

The set of signs shall be able to operate in this The set of signs shall be able to operate in this location for an extended period of time. This location for an extended period of time. This means the signs will be able to stand up to all means the signs will be able to stand up to all necessary weather conditions and maintain power necessary weather conditions and maintain power under any irregular weather patterns. under any irregular weather patterns.

The system’s electronics will be enclosed in a The system’s electronics will be enclosed in a NEMA 4 rated enclosure. This enclosure will NEMA 4 rated enclosure. This enclosure will protect the system from any moisture or extreme protect the system from any moisture or extreme weather. Electrical components of the system weather. Electrical components of the system shall be able to function from -25 to 80 degrees shall be able to function from -25 to 80 degrees Celsius.Celsius.

Functional RequirementsFunctional Requirements

Pushbutton activationPushbutton activation Programmable integrated chipProgrammable integrated chip Communication networkCommunication network Sign displaySign display

LED’sLED’s Countdown displayCountdown display

ReliabilityReliability Solar charging protectionSolar charging protection

System OverviewSystem OverviewCross Walk System Overview

Countdown Display

Sign Display

Slave Signaling System for Signs

Sign Controller

Signal Control System

Wireless Transmit / Receive Push Button

ControlRelay

Master Control System

PIC

Master Controls

Wireless Transmit / Receive

School In/Out of Session Switch

Power Source / SupplyBattery

Charge Controller

12

V D

C

Real Time Clock

Power Source / SupplyBattery

Charge Controller 1

2V

DC

Flash / Dimmer Module

Legend

Power Line

Signal Line

Physical Physical Implementation/DesignImplementation/Design

Power Supply and Charging Power Supply and Charging SystemSystem

Solar PanelSolar Panel Panel Size Determined Panel Size Determined

by Previous SD Group by Previous SD Group Excel SoftwareExcel Software

Compatibility with 12 Compatibility with 12 volt base systemvolt base system

Charge ControllerCharge Controller Controller Needed to Controller Needed to

Regulate ChargingRegulate Charging Needs to be able to Needs to be able to

handle maximum handle maximum current and voltage current and voltage from panelfrom panel

Power Supply and Charging Power Supply and Charging SystemSystem

BatteryBattery 12 Volt System Capability12 Volt System Capability Used previous SD team Used previous SD team

software for battery software for battery sizingsizing

Needs to be able to Needs to be able to handle load during low handle load during low charging times, i.e. night charging times, i.e. night and very cloudy daysand very cloudy days

3-5 Days without sun for 3-5 Days without sun for sizing battery was sizing battery was recommended from recommended from several solar power several solar power supplierssuppliers

Micro ControllerMicro Controller

Serial Interface: yes

Frequency: 2.4 to 2.431 GHz

Operating Temperature: -30 to 70 C

Outdoor Range: 500 fts

RF Interface:Integrated Antenna

Supply Voltage: 3 VDC

Transmit Current: 18 mA

Receiver Current: 15 mA

Transmit Power: 0 dbm

Size: 1.9x1.2x.14 inch

Pin Count: 28

No addressing or programming

High noise immunity

Serial Interface: yes

Operating Temperature: -40 to 70 C

Baud Rate:2.4 or 9.6 kbps

Supply Voltage: 2 to 5.5 VDC

Supply Current (at 3VDC): .7 mA

Size: .31x.37x.16 inch

Pin Count: 8

Transceiver Encoder/Decoder

Micro ControllerMicro ControllerWiring Diagram

Micro ControllerMicro Controller

FunctionalityFunctionality• Take input from the push buttonTake input from the push button• Transmit signals to the PICTransmit signals to the PIC• Receive signals from the PICReceive signals from the PIC• Decode the PIC signalsDecode the PIC signals• Activate/deactivate LED’s and Activate/deactivate LED’s and

countdown timercountdown timer

Master SystemMaster System This subsystem is the This subsystem is the

main functionality main functionality controller for the controller for the overall project.overall project.

This system will This system will contain first and contain first and foremost a foremost a Programmable Programmable Integrated Chip, or Integrated Chip, or PIC, that will interface PIC, that will interface with other components with other components to facilitate overall to facilitate overall system functionality.system functionality.

Master System Master System (Support (Support Components)Components)

The receiver IC will accept the The receiver IC will accept the incoming coded WWVB incoming coded WWVB broadcast via it’s antenna and broadcast via it’s antenna and send the information to the send the information to the microcontroller for decoding.microcontroller for decoding.

This antenna is specially tuned This antenna is specially tuned to receive a 60 kHz, low to receive a 60 kHz, low frequency transmission called frequency transmission called WWVB. WWVB.

The Real Time Clock (RTC) is The Real Time Clock (RTC) is used for time keeping used for time keeping capability for the master capability for the master system.  system. 

The RTC has an internal 32 The RTC has an internal 32 kHz crystal oscillator is kHz crystal oscillator is provided to maintain this time, provided to maintain this time, as well as clock adjustment as well as clock adjustment function to correct the function to correct the oscillator slight variance in oscillator slight variance in accordance to environmental accordance to environmental temperature. temperature. 

Antenna and Receiver IC

Receiver IC Block Diagram

Real Time Clock Block Diagram

Master System (PIC)Master System (PIC)

The microcontroller is the “brains” of this device.The microcontroller is the “brains” of this device. This PIC is rated for extreme weather conditions This PIC is rated for extreme weather conditions

and has the capability to communicate with any and has the capability to communicate with any transceiver chosen for communications between transceiver chosen for communications between the master subsystem and slave subsystem.the master subsystem and slave subsystem.

It has an 8-bit architecture with 14 KB of Flash It has an 8-bit architecture with 14 KB of Flash memory and 368 bytes of RAM.memory and 368 bytes of RAM.

LED’sLED’s The LED cluster was chosen for this system to The LED cluster was chosen for this system to

ensure visibility at 925 feet. The LED color was ensure visibility at 925 feet. The LED color was based upon the color of the crosswalk sign. based upon the color of the crosswalk sign.

The clusters have a BS15 base, which is a The clusters have a BS15 base, which is a common base for automotive applications. The common base for automotive applications. The LED clusters operate on a 12 Volt base which is LED clusters operate on a 12 Volt base which is compatible with many solar cell applications. compatible with many solar cell applications.

Flasher-Dimmer ModuleFlasher-Dimmer Module This module is used to satisfy the federal regulations This module is used to satisfy the federal regulations

regarding flashing rates. In addition, the module provides regarding flashing rates. In addition, the module provides dimming capabilities given the outdoor lighting. dimming capabilities given the outdoor lighting.

60 flashes per minute 60 flashes per minute The accuracy of this unit allows for stability of +/- 1 flash per The accuracy of this unit allows for stability of +/- 1 flash per

minute. minute. The dimming capability of the module will help save what The dimming capability of the module will help save what

would otherwise be wasted power. A maximum dimming would otherwise be wasted power. A maximum dimming percentage can be set by the user. A photoresistor is percentage can be set by the user. A photoresistor is included with this module to monitor light conditions. included with this module to monitor light conditions.

Component EnclosureComponent Enclosure Certain components of the crosswalk system will need to be Certain components of the crosswalk system will need to be

protected from vandalism and adverse weather conditions. To protected from vandalism and adverse weather conditions. To achieve this, all electrical components that do not already have achieve this, all electrical components that do not already have weather protection will be placed inside this locking enclosure. weather protection will be placed inside this locking enclosure.

The enclosure needs to allow for transmission and reception of The enclosure needs to allow for transmission and reception of signals. This requires that the enclosure be made of plastic signals. This requires that the enclosure be made of plastic instead of metal. instead of metal.

The exact size of the enclosure will depend solely on the size of The exact size of the enclosure will depend solely on the size of the battery chosen by the group. the battery chosen by the group.

Design EvaluationDesign EvaluationMay07-01 Design Evaluation

Functionality

Relative Importance

(%)

EvaluationScore (%)

ResultantScore

Will flash signs when requested from the attached button 20% 100% 20%

Automatically flashes signs during high traffic times (class transitions) 20% 100% 20%

Signs successfully sends and receives information with the master controller 20% 100% 20%

Countdown display will turn on and off at the appropriate times in conjunction with the flashing LED’s 15% 100% 15%

System will be able to operate only on solar power 10% 100% 10%

System will comply with all known traffic laws and standards 10% 100% 10%

Systems will be able to operate under all weather conditions 5% 100% 5%

Total 100%   100%

QuestionsQuestions