Arduino RFID Unlock Mac (Linux and Win)


Introduction: Arduino RFID Unlock Mac (Linux and Win)

I've a macbook pro, I've also a big password on my macbook. When the mac goes on stop, I do write the pass for open the system. In a normal day I digit the password something like 100 times. Now I've found the solution! The RFID TAG!

I use an Arduino micro, and an RFID sensor tag for unlock my computer by keychain.

Follow my Instructables, and UNLOK your computer without touching keyboard.


Arduino Micro (China) or Arduino Leonardo

RFID Shield RC-522

3.3 voltage regulator



Step 1: Connect the Hardware

For this project you do use an Arduino/Genuino Leonardo on pro micro. The reason is implicit on the project. When you use the rfid tag near the Arduino, it send the letters of your password to your system. Your computer read the atmega32u4 like a keyboard. In the code of Arduino there is your system password. This password will be wrote on screen when you present the TAG. For this reason, the connections to RFID RC-522 of this Instructables are fits for an Arduino Leonardo or Arduino Micro (China). Follow the scheme and see the image. Connect all the pin. Pay more attention to connect the 3.3V pin of RFID shield to voltage regulator. You can burn the shield.

You can use also an Arduino Pro micro 3.3V, without voltage regulator.

1 SDA 10




5 IRQ *


7 RST Reset

8 +3.3V Volt regulator --> 3.3V

Step 2: Upload the Code

Before uploading the code, write your TAG code, and install the MFRC522 library by using

After this connect the Arduino to computer, and upload the code in the file.

Step 3: Try the Code

Well! it's time to try!
Open a Text Editor, and connect your Arduino to computer. Try to approach your TAG to the RFID reader. If all is OK, you can see your password on text editor. It works?!



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    12 Discussions

    How to do "control+alt+canc"? My laptop need it for unlock before to insert user and password

    2 replies

    See the keyboard library.

    I've correct the error. Now you can download the file.

    and you have also a mistake typt in the cade .look at the firts 2 pins pin 9 and 10 you typt (SAD RST)?? must that not be SDA? on pin 10??

    1 reply

    the link is NOT working to the github??


    and can you also tel me the pin connections for the NANO, i dont get it, you use a micro with orher pinouts and so, i am rather new to Arduino so a bit of help is needed to say I MADE IT, i also am first trying it with a breadbord on a UNO. but also there is the pin outs and colors different.??

    os it possible to assist.

    for the NANO and UNO and the github code thats not working or so

    1 reply

    Great! Follow the Instructable :-)