AUTOMOTIVE EMBEDDED SYSTEMS

PROJECT

MOTORBIKE ANTI-THEFT ALARM WITH

SPARK CUT OFF AND TILT SENSOR

Submitted by:

ANISH KRISHNAN (CB.EN.P2.ATE.13002)

ARJUN HAREENDRAN (CB.EN.P2.ATE.13003)

INTRODUCTION

The security of a vehicle is an important aspect as the vehicle theft and related issues are on

a rise in the contemporary scenario. The relevance of a good anti-theft system to protect the vehicle

is more in this context. The threat of vehicle theft is more in the case of two wheelers like motor

bikes when compared to that of four wheel vehicles like cars. So the employment of an anti-theft

system in a motor bike is highly significant. The anti-theft system we aim to develop through this

project is an electronic circuit based system which can prevent the theft of the vehicle in two ways.

It cuts off the ignition, thus preventing the engine start and also a warning alarm is produced. The

circuit is very compact and can be hidden anywhere, without any complicated wiring. Virtually, it

suits all bikes as long as they have a battery. It doesn't drain out the battery though as the standby

current is zero.

CIRCUIT DIAGRAM

COMPONENTS REQUIRED

Name Component Value/NameR1 Resistor 470ΩR2 Resistor 2.2KΩR3 Resistor 220ΩR4 Resistor 1.5MΩR5 Resistor 470ΩR6 Resistor 1.5MΩ

R7 Resistor 1KΩR8 Resistor 220KΩR9 Resistor 4.7KΩC2 Capacitor 10µF,25VC3 Capacitor 10µF,16VT1 Transistor BS 170T2 Transistor BS 170T3 Transistor BC 548T4 Transistor SL 100/BEL 187D1 Diode 1N4148D2 Diode 1N4007

ZD1 Zener Diode 3.3VRL1C1 Relay ContactsRL1C2 Relay Contacts

RL1 Relay 12V,2C/OIC1 Integrated Circuit UM3561S1 Hidden switchS2 Ignition switchS3 Shock/Tilt switch

LS1 Loud Speaker 4Ω,0.5WBattery 12V

Spark Plug

WORKING

The hidden switch S1 can be a small push-to-on switch, or a reed switch with magnet, or

any other similar simple arrangement. The circuit is designed around a couple of low-voltage

MOSFETs configured as monostable timers. Motorbike key S2 is an ignition switch, while switch

S3 is a tilt switch.

Motorbike key S2 provides power supply to the gate of MOSFET T2, when turned on.

When you turn ignition off using key S2, you have approximately 15 seconds to get off the bike;

this function is performed by resistor R6 to discharge capacitor C3. Thereafter, if anyone attempts

to get on the bike or move it, the alarm sounds for approximately15 seconds and also disconnects

the ignition circuit.

During parking, hidden switch S1 is normally open and does not allow triggering of

MOSFET T1. But when someone starts the motorbike through ignition switch S2, MOSFET T2

triggers through diode D1 and resistor R5. Relay RL1 (12V, 2C/O) energises to activate the alarm

(built around IC1) as well as to disconnect the ignition coil from the circuit. Disconnection of the

ignition coil prevents generation of spark from the spark plug. Usually, there is a wire running from

the alternator to the ignition coil, which has to be routed through one of the N/C1 contacts of relay

RL1 as shown in the circuit diagram. Also, on disconnection of the coil, sound generator IC

UM3561 (IC1) gets power supply through N/O2 contact of relay RL1. This drives the Darlington

pair built around T3 and T4 to produce the siren sound through loudspeaker LS1.

To start the vehicle, both hidden switch S1 and ignition key S2 should be switched on.

Otherwise, the alarm will start sounding. Switching on S1 triggers SCR1, which, in turn, triggers

MOSFET T1. MOSFET T1 is configured to disable MOSFET T2 from functioning. As a result,

MOSFET T2 does not trigger and relay RL1 remains de-energised, alarm deactivated and ignition

coil connected to the circuit.

Connection to the ignition coil helps in generation of spark from the spark plug. Keeping

hidden switch S1 accessible only to the owner prevents the bike from pillaging.

Tilt switch S3 prevents attempt to move the vehicle without starting it. Glass-and metal-

bodied versions of the switch offer bounce-free switching and quick break action even when tilted

slowly. Unless otherwise stated, the angle by which the switch must be tilted to ensure the contact

operation (operating angle), must be approximately 1.5 to 2 times the stated differential angle. The

differential angle is the measure of the 'just closed' position to the 'just open' position.

COST OF IMPLEMENTATION

Component Cost( )₹Resistors 5

Capacitors 2Transistors 15

Diodes 2Relay Contacts 30

Relay 15Switches 15

Zener Diode 1IC 5

Loud Speaker 15Bread Board 100

Miscellaneous (connecting wire etc...) 25Total 230

CONCLUSION

The motorbike anti-theft system is a very useful technology that adds the security of the

vehicle. It is a simple and effective technology which can be easily mounted on any motorbike

without having much modifications to the existing systems. The cost of implementation for this

system is very low and it is very much affordable. The level of protection it offers, the compactness

and affordability makes this technology a feasible one.