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.
Step 1: Arduino and Fingerprint Sensor
You can buy the Arduino Uno from any of these online stores:
fingerprint sensor is available from:
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.