The ignition system of a vehicle typically consists of the key cylinder as well as a key which is kept in such a way that it can allow the vehicle to remain in the running state even when the key is removed. A timer is set in such a way that the time delay from leaving the engine running should be less than a threshold value. In the second set of security check, the engine is shut down when the vehicle fails to meet the second set of security conditions.

Hardware used:
AT command supporting mobile phone
microcontroller
relays and relay driver IC
Voltage regulator
diode
GSM enabled mobile phone

Two mobile phones are used: one in the user's hand and the other in the car and connected to the microcontroller. AT command id used as the communication protocol between the two devices. The microcontroller can read the SMS recieved by the mobile phone and then identify the command from the mobile. The vehicle is ignited or stopped accordingly.

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