17-12-2012, 02:27 PM
PROJECT REPORT ON OVER SPEED ALARM FOR TWO WHEELERS
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AN INTRODUCTION TO 509 ARMY BASE WORKSHOP
509, Army Base Workshop is an electronics base repair and overhaul agency of Army. 509, Army Base Workshop was established on 1st May, 1943 to meet defense needs of the Government of India. It is an ISO 9001:2000 certified repairing army workshop. The primary load of the workshop is in the field of electronics equipments, both line and communication equipments. In addition to the repair of centrally repairable modules, calibration of test equipments is also entrusted to FON.
To fulfill the role, the Workshop is organized into three major functional groups, viz. Works, Production and Administration. Planning, progressing and production control, material control activities, Workshop services and automation functions are performed by Works group. Production group is responsible for the execution of repair and overhaul programmed assigned to the Workshop. Administration group looks after the administration of combatant and civilian employees. An Ordnance Store Section (OSS) attached to this Workshop is responsible for provisioning of spares. The resident inspector performs quality control function. A CMO is authorized to give medical support to Workshop. A civilian Assistant Labour Welfare Commissioner (ALWC) is authorized to ensure the welfare and industrial safety of civilian employees. A Software Development Cell and Army Repair and Calibration Cell (ARCC) are also authorized over and above the PE of 509, Army Base Workshop.
INTRODUCTION
Riding of two wheeler gives constant attenuation. The moment you become unmindful of the high speed, applying sudden breaks to avoid obstracles may lead to an accident.
An overspeed alarm can be of great helpful to avoid such situations. It acts like a watchful friend that warns
you or make you aware whenever you drive faster than the set speed limit.
So here we are using a simple circuit given further with a property of Hall effect. Hall effect sensor is the bone of this circuit. Over speed indicator totally depends on this sensor and the complete kit should be placed on the handle and the speaker magnate is at the wheel drum. The whole circuit uses 12v battery as the voltage source.
Working principle:
Over speed alarm based on Hall effect. That is:
“When a current carrying conductor is placed in a magnetic field, a voltage is introduced perpendicular to both the current and the field. This is known as hall effect”.
As shown in component list the A1302 used for hall sensor IC, which gives the output proportional to an applied magnetic field. It includes a linear amplifier and a CMOS class A output structure. LED1 indicates high pulse o/p. the output of LM358 applied to LM2917N consisting an input amplifier, a versatile op amp comparator, with an active zener and converts the frequency into proportional voltage. Its o/p is filtered by C4 & C5 and applied to TL071. It is wired as differential amplifier. The o/p of IC3 is proportional to the speed change is amplified by op amp IC4.
The output of IC4(pin 6) is fed to comparator CA3130 and compared with reference voltage. The comparator provides regulated 3.3v (via zener diode) to music generator UM66.
The output of UM66 drives speeker LS1 with the help of transistor T1. To sound the alarm whenever the two wheeler over speed.
CONSTRUCTION & FORMULA:
Take a multipurpose IC and assemble all the components as in layout. Now calibrate the circuit.
Let we want to see the speed limit for two wheeler to 40kmps. For this first we find out the corresponding rotational frequency of wheel using formula:
[Speed(in kmph)*10^5]/[diameter(in cm)*π*3600] HZ
For a 56cm dia from wheel and a speed of 40 kmph, it is calculated to be 6 hz. Apply a 6hz square wave signal from a function generator to pin 2 of pulse generator IC2 via resistor R1. Adjust VR1 such that LED1 glows brightly. Now adjust preset VR2, VR3 and VR4 to sound the speeker. Now if you reduce the input signal frequency at IC2, LED1 should go off and audio alarm stops.
Resistors
A resistor is a two terminal electronic component that produces a voltage across its terminal that is proportional to the electric current passing through it in accordance with ohm’s law
Resistance
Resistance is the property of a component which restricts the flow of electric current. Energy is used up as the voltage across the component drives the current as heat.
Resistors used in electronics can have resistances as low as 0.1Ω or as high as 10MΩ.size and position of the leads are relevant to equipment designers; resistors must be physically large enough not to overheat when dissipating power.
TRANSISTOR BC548
The transistor is a component with 3electric wires coming out of it. They are named B(base), C( collector) and E ( emitter).
A transistor is a semiconductor device used to amplify and switch electronic signals. It is made of a solid piece of semiconductor material, with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor’s terminals changes the current flowing through another pair of terminals. Because the controlled(output) power can be much more than the controlling (input) power, the transistor provides amplification of a signal. Today, some transistors are packed individually, but many more are found embedded in integrated circuit.
Transistor as a switch
Transistors are commonly used as electronic switches, both for high- power applications such as switched mode power supplies and for low power applications such as logic gates.
Transistor as an amplifier
The common emitter amplifier is designed so that a small change in voltage in (vin) changes the small current through the base of the transistor and the transistor’s current amplification combines with the properties of the circuit mean that small swings in vin produce large change in vout.
Here we are using BC 548 which is a general purpose low power IC used for amplification.