Turn Your Fingerprint Sensor Into Biometric Toggle Switch




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

After I've made my first fingerprint sensor project to read my fingers and recognized me, I became obsessed with biometric system and was curious if i could use fingerprint to turn on and off a device. It was possible to open a lock of the door using fingerprint, but, what about closing or locking the door? then I started to think of turning on and off an light bulb using fingerprint too but it is dangerous working with high voltage AC circuits, so instead of a light bulb, I will just use an LED to try my idea and maybe later on, use a light bulb with some relay on it or maybe opening and closing door or motorized gate.

materials needed:


blue LED

220ohms resistor

fingerprint sensor

Step 1: Arduino and Fingerprint Sensor

Step 2: Enrolling Your Finger Using Windows Software

Download and install the SFGdemo software ( works on windows only).

Load the blank.ino file on your Arduino.

Connect the fingerprint sensor on Arduino as shown in the photo.

Open the SFGdemo software then start enrolling user's finger.

Step 3: The Circuit

The basic idea is to make the fingerprint sensor to act like a switch which it could toggle on and off an LED. We are making an intelligent switch that can only be activated by you or registered users. This could be helpful if you want to personalize your electrical devices.

This biometric LED is very simple circuit to build. Connect the components based on the provided diagram and you're on the way to get started.

Step 4: Loading the Main Program

Download the fingerprint library from Adafruit.

Add the library to your Arduino library.

Download the FPStoggle.ino file and load into your Arduino.

You're ready to go.

Step 5: Hello World..............

Make it Glow!

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    6 Discussions


    Question 3 months ago

    Hello is there anyway I can use a switch statement on a fingerprint sensor. (I mean is it possible for me to verify finger print if fingerprint matches 70% with a fingerprint in the system? )


    Question 10 months ago on Step 5

    HI I want to make a similar project but instead of turning a light on I wanted to have the fingerprint sensor to close a relay briefly. Is this possible. I am new to this and need help.....

    R Jordan Kreindler

    2 years ago

    A super idea. I will try to implement it shortly. Congratulations on a great Instructable.


    3 years ago

    hello, the fingerprint module i bought has different specs than this, can you help with the program. this is the model (ADST11SD300&310)