LED-Outlined Traffic Signs on the ISU Campus Jacob Bonner Dustin Nekvinda Hieu Pham Brian Schnurr David Wallace May 07-01

Project Overview The goal of this project is to implement a set of diamond shaped pedestrian cross-walk signs that will stand out and alert drivers to potential dangers. The goal of this project is to implement a set of diamond shaped pedestrian cross-walk signs that will stand out and alert drivers to potential dangers. The signs will have light emitting diodes (LED’s) that will flash to get the driver’s attention. The signs will have light emitting diodes (LED’s) that will 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 wireless signal. The signs will communicate with the master system via wireless signal. The system will also be equipped with countdown timers that inform the pedestrians of the time they have remaining to cross the street before the sign’s LED’s stop flashing. The system will also be equipped with countdown timers that inform the pedestrians of the time they have remaining to cross the street before the sign’s LED’s stop flashing. The system will be powered by a solar panel/battery back-up power source. The system will be powered by a solar panel/battery back-up power source. It is the intent of this project to reduce possible accidents and violations by alerting the driver to a potentially dangerous situation. It is the intent of this project to reduce possible accidents and violations by alerting the driver to a potentially dangerous situation.

Intended Users and Uses The system designed in this project is intended to be used by Iowa State University Department of Public Safety. The system will be set up to operate on its own with minimal interaction necessary. Once implemented, the only interaction with the system shall be when the automatic flashing time needs to be changed, or during out-of-session breaks when the over-ride switch will need to be flipped. The system designed in this project is intended to be used by Iowa State University Department of Public Safety. The system will be set up to operate on its own with minimal interaction necessary. Once implemented, the only interaction with the system shall be when the automatic flashing time needs to be changed, or during out-of-session breaks when the over-ride switch will need to be flipped. After installation the intended users will include motorists and pedestrians. Pedestrians will rely on the system to provide a heightened sense of awareness for the drivers. This is intended to reduce the danger to pedestrians crossing campus streets. After installation the intended users will include motorists and pedestrians. Pedestrians will rely on the system to provide a heightened sense of awareness for the drivers. This is intended to reduce the danger to pedestrians crossing campus streets. The intended use of this system is to alert drivers of situations that may involve pedestrians on the roadway. It is designed to allow pedestrians to cross the street safely and tell drivers that there is a heightened chance of pedestrians in the street. The system will be placed where there is already a cross-walk, but more attention needs to be drawn to it. The intended use of this system is to alert drivers of situations that may involve pedestrians on the roadway. It is designed to allow pedestrians to cross the street safely and tell drivers that there is a heightened chance of pedestrians in the street. The system will be placed where there is already a cross-walk, but more attention needs to be drawn to it.

Operating Environment The operating environment will be a recommended location on the Iowa State University campus to be determined by a CCEE undergraduate course taught by Professor Shauna Hallmark. The operating environment will be a recommended location on the Iowa State University campus to be determined by a CCEE undergraduate course taught by Professor Shauna Hallmark. The set of signs shall be able to operate in this location for an extended period of time. This means the signs will be able to stand up to all necessary weather conditions and maintain power under any irregular weather patterns. The set of signs shall be able to operate in this location for an extended period of time. This means the signs will be able to stand up to all necessary weather conditions and maintain power under any irregular weather patterns. The system’s electronics will be enclosed in a NEMA 4 rated enclosure. This enclosure will protect the system from any moisture or extreme weather. Electrical components of the system shall be able to function from -25 to 80 degrees Celsius. The system’s electronics will be enclosed in a NEMA 4 rated enclosure. This enclosure will protect the system from any moisture or extreme weather. Electrical components of the system shall be able to function from -25 to 80 degrees Celsius.

Functional Requirements Pushbutton activation Pushbutton activation Programmable integrated chip Programmable integrated chip Communication network Communication network Sign display Sign display LED’s LED’s Countdown display Countdown display Reliability Reliability Solar charging protection Solar charging protection

System Overview

Physical Implementation/Design

Power Supply and Charging System Solar Panel  Panel Size Determined by Previous SD Group Excel Software  Compatibility with 12 volt base system Charge Controller  Controller Needed to Regulate Charging  Needs to be able to handle maximum current and voltage from panel

Power Supply and Charging System Battery 12 Volt System Capability Used previous SD team software for battery sizing Needs to be able to handle load during low charging times, i.e. night and very cloudy days 3-5 Days without sun for sizing battery was recommended from several solar power suppliers

Micro Controller Serial Interface: yes Frequency: 2.4 to 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 TransceiverEncoder/Decoder

Micro Controller Wiring Diagram

Micro Controller Functionality Take input from the push button Take input from the push button Transmit signals to the PIC Transmit signals to the PIC Receive signals from the PIC Receive signals from the PIC Decode the PIC signals Decode the PIC signals Activate/deactivate LED’s and countdown timer Activate/deactivate LED’s and countdown timer

Master System This subsystem is the main functionality controller for the overall project. This system will contain first and foremost a Programmable Integrated Chip, or PIC, that will interface with other components to facilitate overall system functionality.

Master System (Support Components) The receiver IC will accept the incoming coded WWVB broadcast via it’s antenna and send the information to the microcontroller for decoding. This antenna is specially tuned to receive a 60 kHz, low frequency transmission called WWVB. The Real Time Clock (RTC) is used for time keeping capability for the master system. The RTC has an internal 32 kHz crystal oscillator is provided to maintain this time, as well as clock adjustment function to correct the oscillator slight variance in accordance to environmental temperature. Antenna and Receiver IC Receiver IC Block Diagram Real Time Clock Block Diagram

Master System (PIC) The microcontroller is the “brains” of this device. This PIC is rated for extreme weather conditions and has the capability to communicate with any transceiver chosen for communications between the master subsystem and slave subsystem. It has an 8-bit architecture with 14 KB of Flash memory and 368 bytes of RAM.

LED’s The LED cluster was chosen for this system to ensure visibility at 925 feet. The LED color was based upon the color of the crosswalk sign. The LED cluster was chosen for this system to ensure visibility at 925 feet. The LED color was based upon the color of the crosswalk sign. The clusters have a BS15 base, which is a common base for automotive applications. The LED clusters operate on a 12 Volt base which is compatible with many solar cell applications. The clusters have a BS15 base, which is a common base for automotive applications. The LED clusters operate on a 12 Volt base which is compatible with many solar cell applications.

Flasher-Dimmer Module This module is used to satisfy the federal regulations regarding flashing rates. In addition, the module provides dimming capabilities given the outdoor lighting. This module is used to satisfy the federal regulations regarding flashing rates. In addition, the module provides 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 minute. The accuracy of this unit allows for stability of +/- 1 flash per minute. The dimming capability of the module will help save what would otherwise be wasted power. A maximum dimming percentage can be set by the user. A photoresistor is included with this module to monitor light conditions. The dimming capability of the module will help save what would otherwise be wasted power. A maximum dimming percentage can be set by the user. A photoresistor is included with this module to monitor light conditions.

Component Enclosure Certain components of the crosswalk system will need to be protected from vandalism and adverse weather conditions. To achieve this, all electrical components that do not already have weather protection will be placed inside this locking enclosure. Certain components of the crosswalk system will need to be protected from vandalism and adverse weather conditions. To achieve this, all electrical components that do not already have weather protection will be placed inside this locking enclosure. The enclosure needs to allow for transmission and reception of signals. This requires that the enclosure be made of plastic instead of metal. The enclosure needs to allow for transmission and reception of signals. This requires that the enclosure be made of plastic instead of metal. The exact size of the enclosure will depend solely on the size of the battery chosen by the group. The exact size of the enclosure will depend solely on the size of the battery chosen by the group.

Design Evaluation May07-01 Design Evaluation Functionality Relative Importance (%) Evaluation Score (%) Resultant Score Will flash signs when requested from the attached button20%100%20% Automatically flashes signs during high traffic times (class transitions)20%100%20% Signs successfully sends and receives information with the master controller20%100%20% Countdown display will turn on and off at the appropriate times in conjunction with the flashing LED’s15%100%15% System will be able to operate only on solar power10%100%10% System will comply with all known traffic laws and standards10%100%10% Systems will be able to operate under all weather conditions5%100%5% Total100%

Questions