Introduction: RFID Computer Lock
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:
Step 1: Supplies
Here's what you need:
1 ID-12 RFID Reader (and breakout board)
1 RFID Tag
Step 2: 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
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.
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 = RFID.read();
key += read;
if(key.indexOf("4F0088AE355C") >= 0) Serial.print("unlock"); //Should be changed to your RFID key
Step 4: Processing Code
This is the processing script that you should run on your computer. Take note of how it isn't particularly secure, but it can be easily modified to be secure.
boolean locked = false;
println(Serial.list()); //Prints available ports
port = new Serial(this, Serial.list(), 9600); //Chooses the first available port
robot = new Robot(); //Creates robot
catch (AWTException e)
if (locked == true) robot.mouseMove(0, 0); //If locked, moves mouse to top left corner
while (port.available() > 0)
String input = port.readString();
locked = false; //If anything is recieved it'll unlock. I wasn't trying to make it all that secure
void keyPressed ()
if (key == 'l')
locked = true; //Locks it
if (key == 'u')
//locked = false; //Uncomment this if you're a wimp (or if you're testing)
if (key == ESC)
key = 0; //Disables escape as quit
Step 5: Instructions for Operation
Now that you have built you reader, and have all your code, you may be wonder how it all comes together. Here are the simple operating instructions:
1. Plug in assembled reader.
2. Open up Arduino IDE, and upload supplied code.
3. Open up Processing IDE, and run supplied code.
4. Click into processing script and press 'l' to lock.
5. Hold card over reader to unlock.
It's that simple!
Keep in mind that you should use some precautions when testing the first few times. When building this, I got locked out of my computer many, many times. If you have any errors (like RXTX version mismatch), post them in the comments and I will be able to give you the solution.
Have fun and happy locking! (And unlocking hopefully)