Introducing the Fingerprint Sensor Module
Fingerprint sensor modules, like the one in the following figure, made fingerprint recognition more accessible and easy to add to your projects. This means that is is super easy to make fingerprint collection, registration, comparison and search.
These modules come with FLASH memory to store the fingerprints and work with any microcontroller or system with TTL serial. These modules can be added to security systems, door locks, time attendance systems, and much more.
Prices for this sensor greatly vary from $10 to $50. We recommend checking the Fingerprint sensor module on Maker Advisor that compares the price in different stores. The fingerprint sensor modules featured on Maker Advisor should be compatible with this guide.
Here’s the specifications of the fingerprint sensor module we’re using (you should check your sensor datasheet or the specifications provided by your supplier – they shouldn’t be much different than these):
Voltage supply: DC 3.6 to 6.0V
Current supply: <120mA
Backlight color: green
Baud rate: 9600
Safety level: five (from low to high: 1,2,3,4,5)
False Accept Rate (FAR): <0.001% (security level 3)
False Reject Rate (FRR): <1.0% (security level 3)
Able to store 127 different fingerprints
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Step 1: Sensor Pinout
The sensor has six pins that are labeled in the figure Above.
The fingerprint sensor module used in this project came with really thin wires, so soldering breadboard-friendly wires was needed. We recommend using different colors according to the pin function. In our case:
DNC – white wires
VCC – red wire
TX – blue wire
RX – green wire
GND – black wire
The following table shows how to wire the sensor to the Arduino.
VCC 5V (it also works with 3.3V)
TX RX (digital pin 2, software serial)
RX TX (digital pin 3, software serial)
Step 2: Installing the Adafruit Fingerprint Sensor Library
The easiest way to control the fingerprint sensor module with the Arduino is by using the Adafruit library for this sensor. Follow the next instructions to install the library:
1.Click here to download the Adafruit Fingerprint Sensor library. You should have a .zip folder in your Downloads folder.
2.Unzip the .zip folder and you should get Adafruit-Fingerprint-Sensor-Library-master folder.
3.Rename your folder from Adafruit-Fingerprint-Sensor-Library-master folder to Adafruit_Fingerprint_Sensor_Library folder.
4.Move the folder to your Arduino IDE installation libraries folder
5.Finally, re-open your Arduino IDE.
Step 3: Enroll a New Fingerprint
Having the fingerprint sensor module wired to the Arduino, follow the next steps to enroll a new fingerprint. Make sure you’ve installed the Adafruit Fingerprint Sensor library previously.
1.In the Arduino IDE, go to File > Examples > Adafruit Fingerprint Sensor Library > Enroll.
2.Upload the code, and open the serial monitor at a baud rate of 9600..
3.You should enter an ID for the fingerprint. As this is your first fingerprint, type 1 at the top left corner, and then, click the Send button.
4.Place your finger on the scanner and follow the instructions on the serial monitor.
You’ll be asked to place the same finger twice on the scanner. If you get the “Prints matched!” message, as shown below, your fingerprint was successfully stored. If not, repeat the process, until you succeed.
Store as many fingerprints you want using this method.
Step 4: Finding a Match
You now should have several fingerprints saved on different IDs. To find a match with the fingerprint sensor, follow the next instructions.
1.In the Arduino IDE, go to File > Examples > Adafruit Fingerprint Sensor Library > Fingerprint and upload the code to your Arduino board.
2. Open the Serial Monitor at a baud rate of 9600.
3. Place the finger to be identified on the scan.
4. On the serial monitor, you can see the ID that matches the fingerprint. It also shows the confidence – the higher the confidence, the similar the fingerprint is with the stored fingerprint