31-03-2010, 01:49 PM
SPEED LIMIT ALERT
Presented By:
GROUPMEMBERS
ARUN.C
BAIJU.B.N
AVINESH.S
ANAND.C.G
RAHUL MENON.S
SARABHAI INSTITUTE OF SCIENCE AND TECHNOLOGY
MINIPROJECT 2009-10
BATCH NO:1
INTRODUCTION
We propose to design and build an automobile speed limit alarm which notifies the driver of excessive speeds linked to a speed limit sign by a wireless link.
This alarm will sound when the driver exceeds the speed limit by a specified amount.
PROJECT GOALS
One of our goals for this project are to successfully design a wireless speed-limit alert circuit which is capable of reducing road accidents
Another goal to setup compactable device which can be mounted in vehicles like cars
BLOCK DIAGRAM EXPLANATION
Components Required
R1,R2,R19_______1K 1/4W Resistors
R3-R6,R13,R17_100K 1/4W Resistors
R7,R15__________1M 1/4W Resistors
R8_____________50K 1/2W Trimmer Cermet
R9____________470R 1/4W Resistor
R10___________470K 1/4W Resistor
R11___________100K 1/2W Trimmer Cermet
R12___________220K 1/4W Resistor
R14,R16________68K 1/4W Resistors
R18____________22K 1/4W Resistor
R20___________150R 1/4W Resistor
C1,C7_________100µF 25V Electrolytic Capacitors
C2,C3_________330nF 63V Polyester Capacitors
C4-C6___________4µ7 25V Electrolytic Capacitors
D1,D5______Red LEDs 3 or 5mm.
D2,D3________1N4148 75V 150mA Diodes
D4________BZX79C7V5 7.5V 500mW Zener Diode
IC1__________CA3140 or TL061 Op-amp IC
IC2____________4069 Hex Inverter IC
IC3____________4098 or 4528 Dual Monostable Multivibrator IC
Q1,Q2_________BC238 25V 100mA NPN Transistors
L1_____________10mH miniature Inductor (see notes)
BZ1___________Piezo sounder (incorporating 3KHz oscillator)
SW1____________SPST Slider Switch
B1_______________9V PP3 Battery
Circuit Diagram
CIRCUIT OPERATION
IC1 forms a differential amplifier for the electromagnetic pulses generated by the engine sparking-plugs, picked-up by sensor coil L1. IC2A further amplifies the pulses and IC2B to IC2F inverters provide clean pulse squaring.
The monostable multivibrator IC3A is used as a frequency discriminator, its pin 6 going firmly high when speed limit (settled by R11) is reached. IC3B, the transistors and associate components provide timings for the signaling part, formed by LED D5and piezo sounder BZ1. D3 introduces a small amount of hysteresis.
D1 is necessary at set-up to monitor the sparking-plugs emission, thus permitting to find easily the best placement for the device on the dashboard or close to it. After the setting is done, D1 & R9 can be omitted or switched-off, with battery saving.
During the preceding operation R8 must be adjusted for better results. The best setting of this trimmer is usually obtained when its value lies between 10 and 20K.
You must do this first setting when the engine is on but the vehicle is stationary.
The final simplest setting can be made with the help of a second person. Drive the vehicle and reach the speed needed. The helper must adjust the trimmer R11 until the device operates the beeper and D5. Reducing car's speed the beep must stop.
L1 can be a 10mH small inductor usually sold in the form of a tiny rectangular plastic box. If you need an higher sensitivity you can build a special coil, winding 130 to 150 turns of 0.2 mm. enameled wire on a 5 cm. diameter former (e.g. a can). Extract the coil from the former and tape it with insulating tape making thus a stand-alone coil.
Circuit's current drawing is approx. 10mA. If you intend to use the carËœs 12V battery, you can connect the device to the lighter socket. In this case R20 must be 330R.
Depending on the engine's cylinders number, R11 can be unable to set the device properly. In some cases you must use R11=200K and R12=100K or less.
If you need to set-up the device on the bench, a sine or square wave variable generator is required.
To calculate the frequency relation to RPM in a four strokes engine
Hz= (Number of cylinders * RPM) / 120.
For a two strokes engine the formula is: Hz= (Number of cylinders * RPM) / 60.
Thus, for a car with a four strokes engine and four cylinders the resulting frequency @ 3000 RPM is 100Hz.
Temporarily disconnect C2 from IC1's pin 6. Connect the generator's output to C2 and Ground. Set the generator's frequency to i.e. 100Hz and regulate R11 until you hear the beeps and LED D5 flashes. Reducing the frequency to 99 or 98 Hz, beeping and flashing must stop.
advantages
Its outstanding feature lies in the fact that no connection is required from circuit to engine
Low power consumption
It enables the driver to keep his or her eyes 'on the road' because instead of having to frequently look down at the speedometer to check the speed the instance of exceeding the chosen speed is communicated aurally
Compactable and affordable
application
Adaptable with most internal combustion engine vehicles
LIMITATION
One and only limitation is that it is not suitable for diesel engine vehicles.
REFERENCE
electronics-lab.com
miningaustralia.com
Our sincere thanks to
PROF: RAVI NAMBIAR “(HOD EC DEPT.)
PROF
RABHAKARA WARRIER(ASST HOD)DEEPA.V.T
RESHMI (PROJECT GUIDE)
CONCLUSION
DEVICE IMAGE
MODERN TRENDS
THANK YOU
Read Full report
http://khaterehelectronic/files/23.pdf
