DIY Fingerprint Biometric Arduino Anti-thief Security System




About: Cars. Electronics. Mechatronics. I'm a thinker and maker by blood....

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!

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.

Step 11: It Works!

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31 Discussions


4 years ago on Introduction

thank you very much everyone for the support and the vote. i am very happy with my prize.


4 weeks ago

tnx ... very nice work .... can i add keypad and lcd to set another fingerprints in the car ?
plz replay


2 months ago

hello sir we are implementing this same project on two wheeler so please do help to work on this code and make us to implement this project completely.


Question 3 months ago on Introduction

how about simply to rip out the fingerprint scanner and cross the yellow and green cable? would that start the system??


2 years ago

This is an awesome project, thanks for sharing.

I am going to attempt this on my motorcycle, and maybe I could have the fingerprint close a four pole switch (key turn) and then start the bike.

There is no immobilizer.

Aravind Aby

2 years ago

Can I use another fingerprint sensor instead of Adafruit Optical Fingerprint Sensor?

Will Adafruit Fingerprint Library and SFGDemo v.20 work with an alternate fingerprint sensor??Pls help.


2 years ago

Can i install this system in my skoda fabia???


Reply 3 years ago

just connect the circuit to yhe start button.


3 years ago on Introduction

Hi, I have Digital Persona 4500 Fingerprint Scanner. Can i use it instead of the given Brand you required?

Plz reply, it will a great help for my project:)

1 reply

Reply 3 years ago

im not sure.if the fingerprint has serial line, it should work.


3 years ago on Introduction

Hi I like to put this in my car. I like to know the specifications of materials for purchasing and the arduino coding to write it to arduino board. will you help me?

you have said above that the modified code is in comments but I cant find it. will you help me

1 reply

4 years ago

Wow does your care have 305,000 miles on it? That must be a heck of a ride

2 replies

Reply 4 years ago on Introduction

well yeah it's pretty long journey.. i love road trip and discover places around australia.


3 years ago

Hi. i have 2002 toyota corolla car. can i fix this? Thanks.


3 years ago on Introduction it possible to make the starter turn over with the fingerprint scanner? Like, the car starts up off of that, kind of like a push button starter?