Introduction: Makey Makey/arduino Fingerprint Scanner

About: I love all things programming from making a Led blink on a arduino, to controlling a whole Christmas light show from my phone with raspberry pi and other hardware. If you'd like to see the light show, check ou…

This is a Makey Makey/Arduino fingerprint scanner. The total cost of the project is around $100 (you may already have some of this stuff though so don't be worried about the price!). Follow these steps and you could build one in less than 30 minutes! Links to all items below if you want to buy one.


Step 1: Building a Lego Box

This step you can skip if you do not want a box to house you Arduino, wires, etc.

If you do want to make a box, build how ever you want as long as your Arduino and other stuff can fit in it. Be sure to put holes in it (see picture 1) for your usb cables and a hole for your fingerprint scanner.

Step 2: Wiring Up!

First thing you need to do is put the Arduino in the Lego box(see picture 1). Push the Arduino cord out one of the holes you built. Next push you fingerprint scanner in the hole you made. Most fingerprint scanners have 6 wires: black, red, green, white, yellow, and blue. But you will not need the yellow or blue wires. You may have noticed I taped them in a roll. Connect the red wire to 5V, black to ground, green to digital pin 2, white to digital pin 3. Then hook one wire to digital pin 8 (see picture 3). Do not connect this one to the finger print scanner. Now that your wires are hooked up, build some walls around your Arduino to stop it from moving (see picture 4). Next put your Makey Makey in the box. Mine is above my Arduino. Hook the wire that is in digital pin 8 to the W pin on the back of the Makey Makey.(see picture 5). And now your box should look something like the box in picture 6!

Step 3: Getting the Library

No you don't need to go to a library! You have to go to GitHub and download a library so Arduino can work with the fingerprint scanner. Click here to go strait to the download page. When you get there click the green button that says clone/download. Then click download zip, next click SAVE AS. Not save, it won't work. Save it in your Arduino libraries. Look at the pictures for more details.

Step 4: Enrolling a Fingerprint

Now, open Arduino and go to file, examples, Adafruit fingerprint sensor, enroll (picture 1). Once open, click the upload arrow in the upper left corner next to the check mark (picture 2). Finally, open the serial monitor by going to tools, serial monitor (picture 3). Do as the serial monitor says, then close it when it says "fingerprint saved".

IMPORTANT NOTE: when it tells you to pick a id, go to the top and type 1 then enter. Other wise it won't work.

Step 5: Coding Your Arduino

Now it's time to get your Arduino to read your enrolled fingerprint. First go to file, examples, adafruit fingerprint scanner, then fingerprint (see picture 1). Now this is the hardish part. Go to a spot in the code that says

Void setup(){ then below it type what is circled in red in picture 2. Then go all the way to the to bottom and type above the line that says "return finger.fingerID" and type above it what is circled in red. You can copy then paste the code from below.Once done, connect your Arduino the push upload arrow.

CODE FOR BELOW Void setup()

pinMode(8, OUTPUT);
digitalWRite(8, HIGH);

CODE FOR ABOVE return finger.fingerID;

if(finger.fingerID == 1){

digitalWrite(8, LOW);


digitalWrite(8, HIGH);


Step 6: Scratch Time!

I don't mean like scratch your back. I mean scratch coding! This part is simple. All you have to do is go to scratch, create a project, then use your fingerprint scanner! Click here to go strait to scratch. If your new, you can create a account or just make a project as a guest. Once you get a new project, build some code. It should be something like when key W pressed, switch backdrop to backdrop 1. Make sure to create 2 backdrops. One could say please scan finger. The other could say access granted. Look at the pictures for more help. Now just connect your Makey Makey to your computer, and your Arduino. You may be able to connect your Arduino to a battery pack or outlet, but mine did not work. So I would just plug both into your computer. Other than that, your done!!! If something didn't work, go to the troubleshooting step.

IMPORTANT NOTE: make sure you plug your Arduino in before your Makey Makey. If you don't, it may say you scanned your finger in scratch.

Step 7: Troubleshooting

My fingerprint scanner didn't light up when I plugged in my Arduino.

Make sure all of your wires are connected in the right holes, and that you uploaded your sketch to Arduino. Also make sure you have a fingerprint scanner that can work with Arduino.

My fingerprint scanner lights up, but doesn't do anything on scratch when I scan my finger.

If your Arduino is plugged into a outlet or battery back, try plugging it into your computer. If it is, then check your connects. Also make sure your using the finger you enrolled. If you want to change it, go back to step 4 and repeat that step and every step after it. Make sure you also are using the right key in scratch.

Scratch keeps saying I scanned my finger, but I didn't.

Check your connects from your Makey Makey to Arduino. Also make sure you plug your Arduino in first to your computer first.

My fingerprint scanner lights up a color other than red.

That is perfectly fine, it just means your fingerprint scanner is a little different then the others. It should still work with Arduino though if it lights up any color.

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