Burglar Alarm with Arduino

I recently moved into a shared apartment. And I was tired of my room-mate coming into my room when I was out because "He needed some-things!" But every time I asked him about it, he refused it straight away. So, I thought of using my knowledge to good use and I created a Burglar alarm. The alarm uses a PIR sensor to detect motion and as soon as there is motion, the Arduino sets off a buzzer. It also starts a timer and displays it on an LCD so I know exactly when he entered my room.

The Full Project Details Can Be Found at:

How to Build A Burglar Alarm