Download Crash Monitoring Device

Crash Monitoring Device
For Vehicles
With Four or More Wheels
Allison Smyth
May 5, 2005
Table of Contents
Section
Pages
Abstract
2
Introduction
3-4
Literature Review
5-8
Methodology
9-11
Results and Analysis
12-14
Conclusions – Look into the Future
15-16
Works Cited
17-19
Acknowledgements
20
Appendix A – Materials
21
Appendix B – Data Table
22
Appendix C – Graphs
23-24
Appendix D – Diagrams of the Prototype
25-26
Appendix E – Schematics
27-28
1
Abstract
Car accidents have become a large problem in the United States with the number of
accidents increasing each year. A crash-monitoring device that can be mounted on the front of a
vehicle to warn the driver of a potential frontal accident was developed to reduce the number of
accidents during city and highway driving. This device uses a Polaroid sonar module to
determine the distance between two vehicles and gives the driver a visual warning if he or she is
following too closely. It also determines if the driver is catching up to the vehicle in front of him
or her too quickly and visually warns the driver when necessary. Both of the warnings are based
on the weather condition one is driving in. Though the general concept of this device was
developed, wide scale testing is needed to prove that it would reduce accidents.
2
Introduction
Each year the number of car accidents in the United States steadily increases. In the year
2000, 4,563,000 accidents required emergency department visits. Over 41,800 of these accidents
cost the drivers or passengers their lives. To reduce the risk of minor accidents, which often lead
to major accidents, an automotive collision monitoring system that mounts on the front of a
vehicle was created. This device uses sonar technology to send out signals from the front of the
vehicle it is mounted on, hereafter noted as Vehicle A, to determine the distance to the vehicle in
front of it, hereafter noted as Vehicle B. It monitors the speed of Vehicle A and determines the
speed of Vehicle B relative to Vehicle A. If Vehicle A is traveling at a fixed speed in regard to
Vehicle B, the device will warn the driver of Vehicle A if he is following too closely. If Vehicle
A is traveling faster than Vehicle B, the device will warn the driver of Vehicle A if he is
approaching the vehicle too quickly. It will warn the driver of these potential dangers through a
series of light emitting diodes (LEDs). A green LED tells the driver that he is doing fine, amber
is a warning, and red means slow down immediately.
Currently the device requires the use of an external computer, which calculates the
distance between two vehicles and the rate at which one vehicle is approaching another. The
external computer also determines if a situation is safe, adequate, or dangerous and gives
appropriate warnings. The final prototype will not require an external computer; all the software
will be added to the firmware and implemented in the microprocessor.
The goal of this project was to construct a prototype, which is a scaled down, working
model that is testable on golf carts. The prototype would demonstrate the effectiveness and
practicality of a crash monitoring device to reduce vehicle accidents. Tests for this device would
be conducted at speeds less than 20 miles per hour. An important goal for this project was to
3
make the product affordable, user friendly, and easy to install. This would insure that a device of
this type would be accepted into the automotive world. The ultimate goal for this project is to
implement this product in all vehicles manufactured. Overall, the plan for the project was to
build a prototype of the device to show that it would work before converting it to a large-scale
finished product.
4
Literature Review
Currently Mercedes-Benz S-class cars are equipped with an optional system called
Distronic, which is an “adaptive cruise control system” (Shababb 1). The Distronic system
increases the convenience of cruise control for highway or expressway driving. It is designed to
reduce vehicle speed if it detects a slower moving vehicle up to 150 meters directly ahead of it
(“Distronic Distance Control Safety Watch” 1). That way one can follow the preceding vehicle
at a preset distance; however, the Distronic system “does not react to stationary objects [and] can
only apply a maximum of 20% of the vehicle’s braking power” (Mercedes-Benz 1). The
difference between the system being built as part of this project and the Mercedes system is that
the system being built will be activated for the entire duration of a vehicle’s journey, not only
while the vehicle is in cruise control. The Mercedes system also only warns the driver of a
dangerous condition when the Distronic system cannot slow the vehicle down quickly enough.
This could pose a very dangerous condition. The driver should be warned of a dangerous
situation as it begins to occur, not when it is too late. Unlike the Mercedes system, the one
produced in this project will also warn the driver if his vehicle is approaching a stationary object.
There are many sensors on the market that can be used to determine the distance between
two vehicles. The sensors that are the most practical for use on vehicles are sonar or radar
devices. Sonar is an acronym for sound navigation and ranging system. “[It] is a system that
uses transmitted and reflected underwater sound waves to detect and locate submerged objects or
measure the distances underwater” (Bellis 1). Sonar has recently been adapted for use of
distance measurement in robots. In a sonar ranging device, a speaker (transducer, which is also a
receiver) is used to emit a short burst of sound, which is known as a ping. The sound wave
travels through the air, reflects from a target, and travels back to the transducer in the form of an
5
echo. “The pulse may be at a constant frequency or a chirp of changing frequency” (Bellis 3);
the experiments conducted in this project will only use a constant frequency. By measuring the
time between the ping and the echo, one can determine the distance between the target and the
transducer using the formula d  1  vsound  t , where d is the distance, v is the speed of sound,
2
and t is the time until the transducer hears the echo (Kurtus 1). Once one has found the change
in distance and the time in between echo pings one can find the velocity of Vehicle B (the
vehicle preceding the one with the device) relative to Vehicle A (the vehicle with the device)
using the equation for velocity: change in distance divided by time.
The Polaroid Sonar Module 6500 series is a very popular device for ranging in robotics.
This module will be perfect for the prototype of a crash prevention system since it has a range of
6 inches to 35 feet. The Polaroid device operates off of 5 volts, therefore, a regulator must be
built to be sure that the device receives this constant voltage. “The sonar transmit output is 16
cycles at a frequency of 49.4 kHz” (Technical Specifications for 6500 Series Sonar Ranging
Module 1). This Polaroid module also has a feature that allows one to blank out the device, or in
other words, it allows the programmer to send out another ping before the echo of the original
ping returns. This allows one to get more pings in per second. The prototype being created as
part of this project will not use this feature; however, it is good to know this feature exists for
later prototypes.
For a prototype that operates at low speeds a sonar system would work well; however at
high speeds (as distance between objects grow) the reliability of sonar would be in question.
When conditions include high speeds and a large amount of road noise, a radar device will work
more reliably than a sonar device. A radar system works in the same manner as a sonar system
to measure distance between objects and the velocity of an object in front of one; however, radar
6
systems are more expensive than sonar systems. They use radio waves instead of sound waves,
and they can work at greater distances than sonar. Radar pulses also travel at the speed of light
(rather than sonar pulses traveling at the speed of sound). The time it takes for a radar pulse to
travel to a target and back can be found using the expression 2r/c, where r equals range (distance
to target) and c equals the speed of light. The best feature of radar that makes it seem like the
best choice for a final prototype is that “a radar signal provides its own illumination, thereby
being able to detect targets through bad weather as well as at night” (Anderson 1).
This project will also deal with a microprocessor, which is also known as a central
processing unit (CPU). The microprocessor that will be used is a Motorola 9S12 badge. This
device will be the brains of the sonar unit and will “carry out the instructions contained in the
[firmware]” (fact-index.com 1). The 9S12 microprocessor consists of many ports. The port that
the sonar device will be attached to is Port B. This port was picked because a microprocessor of
this type has certain ports designed for certain functions. Although it really doesn’t matter where
one attaches the unit, some ports are more appropriate than others. The programming language
used to talk to the microprocessor is Assembly. Assembly is used because it is more specific
than most other programming languages, and each command has only one interpretation.
Assembly is “an extremely explicit language and the programmer must take everything into
account” (Yetsko 1). To make sure that the final program for the final prototype has no bugs,
CodeWarrior will be used. This program is an assembler, linker, compiler, editor, loader, and
debugger; therefore, if there are any serious problems with the program, it will find them.
This device also requires the use of electronics, since a power regulator must be built to
distribute power to the sonar module and the badge. The power regulator will incorporate
capacitors, a potentiometer, two regulators, and diodes along with a power jack to put power into
7
the entire system. The potentiometer is a large resistor with three-terminals that limits the
voltage that can flow through a certain area (Potentiometer 1). The power supply will require
two regulators because both the badge and the sonar module have certain regulations to the
amount of voltage they can receive at one time. The badge can only have 9 volts while the sonar
module can only take 5 volts. The diodes are used to prevent the regulators from being damaged
when the device is turned off suddenly. If the amount of voltage being applied to the out side of
the regulator is more than the amount being applied to the in side of a regulator, the part will be
destroyed. The diode provides a pathway for the voltage on the out side of the regulator to pass
around instead of through the regulator. The purpose of the capacitors is to smooth out spikes in
the voltage. This allows the sensors to obtain more accurate readings.
8
Methodology
Before beginning the construction of this project, the layout of the initial prototype was
created. It included the sonar circuit board, transducer, power supply, and the 9S12
microprocessor. It was found that a wooden board approximately 8 inches by 6 inches would be
sufficient for housing all of these devices. After designing the general prototype, the power
supply was designed. This device distributes power to the microprocessor and to the sonar
device, which each require different amounts of power. The power supply includes 2 regulators
(one for the microprocessor and one for the sonar unit), an assortment of capacitors and resistors,
a potentiometer, several diodes, a power jack, a LED, and a slide switch (see Appendix A for the
complete list of materials).
The first device built in this project was the power supply. This was an essential part of
the prototype because without it, multiple power cables would need to be run from a battery to
the device. The power supply takes in power from a power jack and sends it to two regulators.
The LM340 Regulator allows only 5 volts of power to pass to the sonar device. The LM317
Regulator allows 9 volts of power to pass to the microprocessor. The LM317 required a
potentiometer to adjust the amount of voltage passing through the regulator. To prevent large
spikes in the current of the circuit, capacitors were used. Diodes are used on the board to make
sure that neither of the two regulators is destroyed if the board is turned off suddenly. The
diodes give the power an alternate pathway to avoid passing back through the regulator and
destroying it.
Once the power supply was built, a wooden board of the dimensions stated above was
acquired. Using wood screws, the sonar circuit board, power supply, and 9S12 badge were
attached to the board. The badge was then connected to the power supply by standard wires.
9
Several more wires ran through the power supply and attached to the microprocessor, to transmit
instructions from the badge to the sonar board. These wires were soldered to the power supply
so that only one ribbon cable would need to attach from the power supply to the sonar circuit
board. During this build phase, a magnetic switch was attached to the power supply through a
cable. It is wired so that one end of the switch receives power and the other end is attached to a
pin on the badge.
A device to hold the transducer was also built. This device was made out of foam and
aluminum to prevent the transducer from vibrating or hearing unwanted sounds. The foam had
to be nonconductive because nearly 200 volts of electricity pass through the transducer during an
initial pulse. The foam also needed to be static proof so that it would not destroy the transducer,
which, like most electronic items, is very susceptible to static electricity. The foam was placed
on the front and the back of the transducer, and was then encased in aluminum. The aluminum
was held together by 8 nuts, bolts, and spacers. The bolts were all placed at a distance 2 cm
greater than the radius of the transducer from the center of the transducer. This design would
insure equal pressure on all parts of the transducer at all times. When this device was completed
it was attached to the prototype using wood screws. The entire prototype was placed in a metal
box (10 by 10 by 4 inches) to prevent radio waves from interfering with the processes on the
board. A picture of the prototype before being put into the metal box and transducer can be
found in Appendix D.
Once the build phase was completed, the firmware for the badge was written in Assembly
and implemented into the 9S12 Badge. The badge was programmed to wait for a “V” or an “E”
command from an outside source. Upon receiving a “V” it would record the time between
pulses of the magnetic switch. This number was then sent to the source asking for “V.” When
10
the badge received an “E” command it would send out a signal for the sonar device to send an
initial pulse. The badge then waits no longer than 150 milliseconds for the pulse to return in the
form of an echo. If no pulse returns in that time, the badge assumes that there is nothing ahead
of the vehicle and sends 150 as the echo time. To test the badge, Hyperterm (a communications
program) was used. In Hyperterm, one could send the commands “V” and “E” and see if the
badge would respond.
The software for the external computer was written in Delphi. This program is written to
send out a “V” and an “E” command when the run button is pressed. The badge should then
return the time it takes for the echo and the time it takes to receive a pulse from the magnetic
switch. The software then converts the times it receives from the badge into feet per second for
the velocity and feet for the echo. The software also has buttons to tell if you are driving in dry,
wet, or snowy conditions. The software is designed to give warnings depending on the weather
condition selected. The warnings determine if one is traveling too close to the preceding vehicle
or if one is approaching the preceding vehicle at too great a speed. The computer informs the
person of the safety of their driving by displaying one of three messages: safe, adequate, or
dangerous.
Once this was completed, an emulator was built to test the software. The emulator was
used in place of the prototype at first to make sure that the software was working before
attaching the prototype. If one attached the prototype immediately and something didn’t work,
one would not know if it was the software or the firmware that was not working. Once the
firmware (Assembly), software (Delphi), and prototype were all deemed to be fully functional,
they were attached together and tested to make sure that they were compatible with each other.
11
Results and Analysis
The device that was built meets many of the initial goals of this project. The device is
capable of determining the distance to Vehicle B (vehicle preceding the vehicle with the device)
using sonar ranging technology. It is also able to determine how quickly Vehicle A (vehicle with
the device) is approaching Vehicle B. Visual warnings are made informing the driver when
Vehicle A is too close or approaching Vehicle B too quickly. The warnings also take into
account the speed of Vehicle A as well as the weather conditions one is driving in: dry, wet, or
icy. Furthermore, the device is affordable, compact, and easy to install. Unfortunately, the
device still incorporates an external computer, which will need to be eliminated to achieve the
ultimate goal of having this device implemented on all vehicles manufactured. In summary, this
prototype has made a great deal of progress since its initial development and now is ready for a
finalization stage.
Both the P.C. software and the microprocessor firmware have been thoroughly tested.
The program in the microprocessor (firmware), was revised several times to be sure that it took
into account special situations such as when Vehicle A’s velocity is zero or when there are no
vehicles preceding Vehicle A. Testing has shown that the warning system is fully functional.
Graphs were made to show the safe and dangerous following distances for vehicles in different
driving conditions. These graphs were used to create the warning system for the prototype.
Below is a graph that demonstrates the safe following distance when one is traveling in dry
conditions.
12
Following Distance
(ft)
Dry Conditions
250
200
150
100
50
0
0
10
20
30
40
50
60
70
80
Vehicle Speed (ft/s)
The blue line (top line) separates the drivers who are following at a safe distance from
drivers who are following at an adequate distance. The pink line (bottom line) separates drivers
who are following at an adequate distance from drivers who are following at a dangerous
distance. A following distance is determined by the speed of the vehicle as well as the weather
condition one is driving in. The lines separating following distances are linear with a positive
slope. This means that the vehicle speed is directly proportional to the following distance.
During dry conditions as a driver increases his speed by 14.6667 ft/s (10 mph) the safe following
distance increases by 44 ft. The other graphs made during this project are similar to this one and
can be found in Appendix C. The data tables for these graphs can be found in Appendix B.
The velocity sensor was tested for its accuracy during this project. To accomplish this, a
device that could spin a shaft with a magnet attached to it at a constant rate was acquired. The
magnetic switch was mounted near the rotating shaft within the range of the magnet. As the
shaft rotated the magnetic switch would receive pulses from the magnet as the magnet rotated by.
Another person was required to count the number of rotations of the shaft per second. From
there, using basic math, one could determine the speed of the shaft. Comparing this answer to
the velocity the P.C. software was calculating from the times given by the magnetic switch, it
could be determined that the velocity readings were accurate (within one foot per second).
13
Testing was also conducted to ensure the accuracy of the sonar ranging device. A book
was held in front of the transducer, and the true distance from the book to the transducer was
measured with a meter stick. This answer was then compared to the value that the program
calculated. It was deemed that this program was accurate within one foot. The ranging
capabilities of the sonar device were also tested during this experiment. It was found that the
sonar device can function accurately up to 80 ft in fair weather conditions.
In the future to ensure greater accuracy of the ranging and velocity readings, the time for
both of these readings will be calculated to more decimal places. Currently the device only finds
readings to milliseconds, and when converted, the readings are not as accurate as they could be.
Overall, this device is fine for experimentations to prove the concept of a warning system of this
type.
14
Conclusion – Look into the Future
A prototype that implements sonar technology to determine if one is following too
closely or approaching a preceding vehicle too quickly was developed. This device is able to
warn the driver of Vehicle A (the vehicle with the device mounted on it) if he is following too
closely or approaching Vehicle B too quickly. It determines if Vehicle A is traveling at safe
distances in regard to Vehicle B depending on the weather condition one is traveling in (dry, wet,
or snowy) and the speed one is traveling at. Although testing is needed to prove that this device
will reduce the number of accidents in the United States, through the experiments that were
conducted as part of this project, it can be assumed that this device will aid in accident reduction.
At times it is difficult to decipher if a situation is truly dangerous. This device not only
determines if a situation is risky, but it also warns one in such a situation.
The three major areas that the prototype constructed throughout this project was tested in
include accuracy in ranging, distance in ranging, and accuracy in velocity readings. It was found
that the prototype is accurate within one foot in echo ranging. The velocity readings were
determined to be accurate within one foot per second. The accuracy of both these devices can be
refined in the future by making adjustments within the firmware implemented in the
microprocessor. The ranging capabilities of the Polaroid transducer were also observed.
According to the technical manuals relating to the Polaroid module, the device is guaranteed for
ranging up to 35 ft; however, testing during this project has shown that under proper conditions
the device has accurate ranging up to 80 ft. It was also found that this would not be sufficient for
accident prevention at speeds greater than 10 miles per hour.
In the future, the software that currently requires an external computer to run will be
completely microprocessor controlled. This improvement will allow the prototype to be a stand-
15
alone device, or in other words, it will be fully functional without any outside inputs (besides a
battery). Without the external computer, a device will need to be developed that can mount on
the dashboard of a car in which the sonar ranging module is incorporated. This device will
allow the driver of the vehicle to input current road conditions and the tire size of his or her
vehicle. This device will then transfer the data to the microprocessor. To receive more accurate
ranging, the final prototype should implement radar ranging. This is due to the facts that radar
waves travel at the speed of light, are resistant to outside sound sources, and can travel large
distances without dispersing. The experiments conducted during this project have shown that
sonar ranging can not reach appropriate distances for high speed traveling. The sonar module
observed in this experiment had a maximum ranging ability of 80 feet, which would not even be
effective at speeds less than 10 miles per hour. Once these improvements have been completed
the project can be expanded further. Someday it could be applied to send signals from the back
of a vehicle as well. This will allow one to tell if he or she is in danger from behind.
16
Works Cited
Anderson, Victor. “Radar Ranging and Tracking: Survey.” IRIS Projects. Aug. 2004. Imaging,
Robotics, and Intelligent Systems Laboratory The University of Tennessee. 22 Sep. 2004
<http://imaging.utk.edu/people/vanderson/radar_task.htm>
Ball, Liz. “Down with dogs and canes? A real life guide to the new electronic mobility gizmos
for visually impaired people.” BBC.com. 2004. BBC. 22 Sep. 2004
<http://www.bbc.co.uk/ouch/closeup/gizmo.shtml>
Bellis, Mary. “The History of Sonar.” About.com. 2004. About. 22 Sep. 2004
<http://inventors.about.com/library/inventors/blsonar.htm>
“Capacitors.” The American Heritage Dictionary. 2000. Houghton Mifflin Compnay. 7 Dec.
2004 <http://dictionary.reference.com/search?q=capacitors>
“Central Processing Unit.” Wickimedia Foundation. 2004. Fact-index. 4 Nov. 2004
<http://www.fact-index.com/c/ce/central_processing_unit.html>
Coledan, Stefano, John McKelvie, Paul Ruben, and James A. Sugar. “Technology Watch.”
Popular Mechanics April 2004: 21-32.
“CPU Design.” Wickimedia Foundation. 2004. Fact-index. 4 Nov. 2004 <http://www.factindex.com/c/cp/cpu_design.html>
“Definition of Laser.” WorldiQ.com. 20 Sep. 2004 <http://www.wordiq.com/definition/Laser>
“Distronic Distance Control Safety Watch.” Autoweb.com. Aug. 1998. 21 Sep. 2004
<http://www.autoweb.com.au/cms/A_50633/newsarticle.html>.
“Exploring Lasers.” Nebne.org. 2002. New England Board of Higher Education. 20 Sep. 2004
<http://www.nebne.org/photonIIsite/lasers.pdf>
Horrell, Paul. “Intelligence: Behold the All-Seeing, Self-Parking, Safety-Enforcing, Networked
17
Automobile.” Popular Science. June 2003: 32-46
Kurtus, Ron. “Echoes.” Succeed in Physical Science. Feb. 2001. 22 Sep. 2004
<http://www.school-for-champions.com/science/echoes.htm>
Loomis, John. Polaroid Sonar Modules. Jan. 1999. 22 Sep. 2004.
<http://www.engr.udayton.edu/faculty/jloomis/ece445/topics/sonar/info.html>
Metcalfe, Nigel. Radar Ranging Theory. Oct. 2001. 22 Sep. 2004
<http://www.dur.ac.uk/3h.physics/radar/node2.html>
Mercedes Benz. Mercedes-Benz Owners Manual. Mercedes-Benz USA, LLC, 2004.
Moyer, Michael. “The Egg That Drives Itself.” Popular Science May 2004: 38-40.
Polaroid. Technical Specifications for 600 Series Instrument Grade Electrostatic Transducer.
Texas: Polaroid-OEM, 2000
“Potentiometers.” The American Heritage Dictionary of the English Language. 2000. Houghton
Mifflin Company. 28 Nov. 2004
<http://dictionary.reference.com/search?q=potentiometer>
“Radar Range, Time, Frequency Calculator.” Radar problems.com. 20 Sep. 2004
<http://radarproblems.com/calculators/rdrcalc1.htm>
“Robotics.” Acroname.com 2004. Acroname Easier Robotics. 22 Sep. 2004
<http://www.acroname.com/robotics/info/articles/sonar/sonar.html>
“Section 2.9: Reflection and Absorption of Laser Beams.” Columbia.edu. 20 Sep. 2004
<http://www.columbia.edu/cu/mechanical/mrl/ntm/level2/ch02/html/12c02s09.html>
Shababb, Nicole. Letter. National Customer Relations Representative, Customer Assistance
Center. 11 Nov. 2004. Mercedes-Benz USA.
“Maintain a Safe Following Distance.” Smart Motorist. 2003-2004. Smart Motorist Inc. 14 Jan.
18
2005 <http://www.smartmotorist.com/tai/tai.htm>
Technical Specifications for 6500 Series Sonar Ranging Module. 2004. Polaroid. 22 Sep. 2004
<http://www.polaroid-oem.com/pdf/6500series.pdf>
“The Doppler Effect.” Expo/Science & Industry/ Whispers From the Cosmos. 1995. NCSA
Board of Trustees, University of Illinois. 20 Sep. 2004
<http://archive.ncsa.uiuc.edu/Cyberia/Bima/doppler.html>
“What You Should Know When Buying a Laser Pointer.” Laser Pointers. DeHarpporte Trading
Company. 20 Sep. 2004 <http://www.users.qwest.net/~dean2/whattono.html>
Yetsko, Michael. Interview. Add on Functions Representative. 23 Nov. 2004.
19
Acknowledgements
A lot of people have given me help and advice on this project, but there are a few people
who I would specifically like to thank. The first is to my research scientist, Mike Yetsko, who
taught me how to program in Assembly, and helped me with the basics of Delphi. He also taught
me basic circuitry, which allowed me to build the power supply mounted on the prototype.
Thanks to his help, I can now make my way through most of these things on my own, only
needing some guidance.
Next I would like to thank my research advisor Mr. Horton, for teaching me about
research papers. This was the first research or science project I had ever done, so data gathering
and report writing were all new to me. Thanks to his help, I have learned the basics of report
writing and can now do an entire project on my own.
Finally, I would like to thank my family (mom, dad, and brother), for helping me with the
project when needed. They were very supportive.
20
Appendix A – Materials
(1) Polaroid Sonar Circuit Board
(1) Transducer
(1) 9S12 Badge
(1) Computer
(1) Radio Shack Perforated Board
(1) Power Jack
(2) Regulators
(1) Wood Board 8” by 6”
(1) Potentiometer
(1) Sliding Switch
(1) LED
(1) Magnetic Switch
(1) Code Warrior Programming Device
(12) Wood Screws
(12) Large Spacers
(2) Pieces of Aluminum
(8) Nuts
(8) Bolts
(8) Small Spacers
An assortment of diodes, capacitors, and resistors
(1) Metal Box 10” by 10” by 4”
21
Appendix B –Data Table
Speed 3 second (x)
14.6667
29.3333
44
58.6667
73.3333
Speed 6 second (x)
14.6667
29.3333
44
58.6667
73.3333
Speed 9 second (x)
14.6667
29.3333
44
58.6667
73.3333
Dry Conditions
Distance 3 second (y)
Speed .5 second (x)
44
14.6667
88
29.3333
132
44
176
58.6667
220
73.3333
Wet Conditions
Distance 6 second (y)
Speed 3 second (x)
88
14.6667
176
29.3333
264
44
352
58.6667
440
73.3333
Snowy Conditions
Distance 9 second (y)
Speed 6 second (x)
132
14.6667
264
29.3333
396
44
528
58.6667
660
73.3333
22
Distance .5 second (y)
7.3333
14.6667
22
29.3333
36.6667
Distance 3 second (y)
44
88
132
176
220
Distance 6 second (y)
88
176
264
352
440
Appendix C – Graphs
Function to determine the proper following distance of a vehicle depending on vehicle speed (Dry conditions)
250
200
Safe Driving Area
150
Distance (ft)
100
Adequate Driving Area
50
Dangerous Driving Area
0
0
10
20
30
40
50
60
70
80
Speed (ft/sec)
Function to determine the proper following distance of a vehicle depending on the vehicle speed (Wet conditions)
500
450
400
Safe Driving Area
350
300
Distance (ft)
250
Adequate Driving Area
200
150
100
Dangerous Driving Area
50
0
0
10
20
30
40
Speed (ft/sec)
23
50
60
70
80
Function to determine the proper following distance of a vehicle depending on the vehicle speed (Snowy conditions)
700
600
500
Safe Driving Area
Distance (ft)
400
Adequate Driving Area
300
200
Dangerous Driving Area
100
0
0
10
20
30
40
Speed (ft/sec)
24
50
60
70
80
Appendix D - Diagrams of the Prototype
Aerial View –
Block Diagram of Aerial View –
Transducer
9S12 Badge
Init
Velocity
Echo
Power Switch
Power Supply
Sonar Circuit
Board
Ribbon Cable
25
Pow er lines
Transducer Picture –
26
Appendix E – Schematics
Power Supply –
Badge Circuitry
27
Badge Pin Purposes
28