Introduction: Arduino RFID Unlock Mac (Linux and Win)

About: I’m degree in Psychology in 2001, with a thesis in Artificial Intelligence. I’m working on Smart Object, IoT and Interactive Design. I’m developing autonomously my projects. I make autonomously programs in Ard…

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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