To create a simple biometric security system to protect your car from unauthorized user, I thought of using fingerprint sensor and Arduino together. This project is based on Adafruit tutorial and for simplicity, I was using the whole program created by them and just modify a little bit the terms used to make it easy to comprehend for the purpose of this application. You will be able to see the modified code in the comments.
Basically, we will modify the starting system of the vehicle. The basic connection is IG from ignition switch will supply voltage to the voltage regulator then to Arduino to turn it on and off, within 10 seconds, scan your finger in the sensor. Finger match will activate the relay that controls the starter relay. Then you can crank the engine. After 10 seconds, the fingerprint sensor will turn off. You can turn it "on" again by cycling the ignition. No finger detected by the sensor within 10 seconds or finger image do not matched, the starting system is disabled and no cranking will occur.
Since every car model do not have the same starting system configuration, be sure to consult your vehicle electrician or check your car’s Electrical Wiring Diagram prior to modifying your vehicle’s starting system. I am very good in vehicle electrical and electronics, so I have no problem modifying my car’s electrical system.
Remember, fingerprint sensor will not crank your engine. It will only activate and deactivate the starter relay to either prevent or allow cranking of the engine.