This instructable will allow you to make an easy RFID lock for your computer, so only people with the correct RFID tag can access it. A program runs on your computer, so when you click into it and press 'l', the mouse automatically goes to the top left corner, and stays there until it is unlocked. It works using processing (with the robot class), an RFID reader, and an Arduino. I would very highly recommend not using this to actually secure something, as it is easily hackable by someone with little experience. With that being said, it can still be used for simple protection against family or co-workers (depending on where you work).

Here is a video of it in action:
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Step 1: Supplies

Here's what you need:

1 ID-12 RFID Reader (and breakout board)
1 Arduino
1 RFID Tag
1 Breadboard
1 Computer

Step 2: Assemble

Picture of Assemble
Solder the RFID reader to the breakout board. Then, wire as follows:
RFID reader pin 1 to ground.
RFID reader pin 2 to 5v.
RFID reader pin 11 to 5v.
RFID reader pin 10 to LED.
RFID reader pin 9 to Arduino pin 6.
RFID reader pin 7 to ground.


Step 3: Arduino Code

Picture of Arduino Code
Here is the code you should upload to your Arduino. You should know the code for your RFID key, so you should change the third to last line accodingly.

#include <SoftwareSerial.h>

SoftwareSerial RFID = SoftwareSerial(6, 7); //RX is 6, TX is 7
String key; //The key that was scanned

void setup ()

  RFID.begin(9600); //Begins connection with the reader
  Serial.println("RFID is all set.");

char read; //The most recent character read

void loop ()
   while(RFID.available() > 0)
      read =;
      key += read;
      if(key.indexOf("4F0088AE355C") >= 0) Serial.print("unlock"); //Should be changed to your RFID key
private_11 year ago


To make this more complete, you could put this in its own executable .jar (with all the required libraries), reduce the dependency on Processing and use the standard java classes (in this case TimerTask and KeyListener) to perform the functionality you want, and add command-line switches to enable/disable pressung 'u' to unlock. This way, you don't have to start up the editor just to run it or tweak the testing parameters.
magique061 year ago
What software do you use to lock the computer screen?
VadimS2 years ago
Looks neat, just cureose, why didn't you have it actually lock the computer. You could have setup the arduino to act like a keyboard, program a macro on it to lock the system, then have the rfid trigger it to type in your password.
alecnotalex (author)  VadimS2 years ago
Interesting idea. I honestly didn't think of that, but now that you mention it, I'll try to figure it out!
Hope it goes well.
megaduty2 years ago
I have the exact same reader and will give your ible a shot later; thanks for the post!