Transcript LED-Outlined Traffic Signs on the ISU Campus

LED-Outlined Traffic Signs on the
ISU Campus
May 07-01
Jacob Bonner
Dustin Nekvinda
Hieu Pham
Brian Schnurr
David Wallace
Project Overview
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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.
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The signs will have light emitting diodes (LED’s) that will flash to get the
driver’s attention.
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During class breaks
On-demand
Override switch
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 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.
Intended Users and Uses
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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.
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
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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 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
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Pushbutton activation
Programmable integrated chip
Communication network
Sign display
LED’s
 Countdown display
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Reliability
Solar charging protection
System Overview
Cross Walk System Overview
Slave Signaling System for Signs
Master Control System
Master Controls
Sign Display
School In/Out of
Session Switch
Countdown Display
PIC
Wireless
Transmit /
Receive
Real Time
Clock
W
ire
Battery
Charge
Controller
12V DC
Power Source / Supply
les
sC
om
mu
nic
Signal Control System
ati
on
Sign
Controller
s
Wireless
Transmit /
Receive
Flash /
Dimmer
Module
Push Button
Control
Relay
Legend
Power Line
Power Source / Supply
Battery
Charge
Controller
12V DC
Signal Line
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
Transceiver
Encoder/Decoder
Serial Interface:
yes
Frequency:
2.4 to 2.431 GHz
Operating Temperature:
-30 to 70 C
No addressing or programming
Outdoor Range:
500 fts
High noise immunity
RF Interface:
Integrated Antenna
Serial Interface:
yes
Supply Voltage:
3 VDC
Operating Temperature:
-40 to 70 C
Transmit Current:
18 mA
Baud Rate:
2.4 or 9.6 kbps
Receiver Current:
15 mA
Supply Voltage:
2 to 5.5 VDC
Transmit Power:
0 dbm
Supply Current (at 3VDC): .7 mA
Size:
1.9x1.2x.14 inch
Size:
.31x.37x.16 inch
Pin Count:
28
Pin Count:
8
Micro Controller
Wiring Diagram
Micro Controller
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Functionality
Take input from the push button
Transmit signals to the PIC
Receive signals from the PIC
Decode the PIC signals
Activate/deactivate LED’s and countdown timer
Master System
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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)
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Antenna and Receiver IC
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Receiver IC Block Diagram
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Real Time Clock Block Diagram
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.
Master System (PIC)
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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
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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.
Flasher-Dimmer Module
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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
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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.
Component Enclosure
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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 exact size of the enclosure will depend solely on the size of the battery
chosen by the group.
Design Evaluation
May07-01 Design Evaluation
Relative
Importance
(%)
Functionality
Evaluation
Score
(%)
Resultant
Score
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%
Questions