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