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.
In this instructable, I am using a 2000 model Mitsubishi Lancer 2-door coupe. It’s my personal car.
Step 1: Materials!
Regulated Power Supply
Resistor 1K ohm
Step 2: The Circuit!
I have modified the wiring diagram so it would be easy to install as much as possible. Take note, this is only applicable for this vehicle model....
Step 3: Program It! Enroll Users
1. Download the Arduino IDE.
2. Install the Arduino IDE.
3. Download the Adafruit Fingerprint Library
4. Add the Adafruit fingerprint to Arduino library.
Open your Arduino IDE. Click Sketch>Import Library>click Add library. Locate the Adafruit fingerprint library folder.
5. Open your Arduino IDE. Click File>Adafruit-Fingerprint-Sensor-Library-Master>click blank.
Load the blank program to your Arduino Uno. This is to make Arduino will not do anything but just act as bridge for PC and Fingerprint sensor.
6. Install the SFGDemo v.20
7. Connect the fingerprint sensor as shown in the diagram.
8. Enroll your fingers using the SFGDemoV2.0.
Step 4: Program It! Load the Main Program
Connect the fingerprint sensor as shown in the diagram and load the main program. Add an LED and resistor at pin 12 to confirm proper circuit operation.
The program is based on Adafruit's Fingerprint tutorial however i have modified the program a little bit and add timer on it to turn off the sensor after 10 seconds in order to avoid distraction from flashing LEDs of the sensor.
Step 5: Build It!
loosen the screws of the under dash. loosen the bonnet release lever. remove the under dash. the blank space is a good spot for the sensor.
Step 6: Build It!
lay-out the fingerprint dimension and cut the area to insert the sensor firmly.
Step 7: Build It!
I found a good spot for the Arduino Uno to be just below the fingerprint sensor. I cut a little this portion for the Arduino Uno to sit properly.
Step 8: Build It!
install firmly the regulated power supply at the back of the driver side under dash.
Step 9: Build It!
Connect all the components as shown in the diagram provided on step no.2.
Step 10: Install It!
Connect the necessary wiring and install the under dash back. Be careful not keep wiring away from any possible short circuit.