Home made security alarms

My garage got broken into 5 years ago at Christmas. After that I wanted but could not afford a security system for the garage, so I went red neck. I set up a baby monitor in the garage with a buzzer on the doors so I could hear what is going on in my shop. 5 years later and I am still using the same system and I must say that I am VERY happy with it. My daughter had the monitor, so it cost me nothing and it gives me peace of mind. So now it is your turn to let the rest of us know what you are using.