Sometimes it is hard to find a nice and safe place to camp. I've been there... and while you need to rest, you pray to be aware when somebody or something is approaching to your tent in the wild. So I recalled this "burglar alarm" I saw on a electronic book years ago. Instead of using a battery infrared sensor (that only works in some directions) remember you need 360 coverage... Then, 1. What about one of those noisy devices available at Radioshack as the alarm, they work with 1.5+ volts. 2. Using a transistor as the switch to trigger the alarm. 3. Use a long copper wire, that once broken, triggers the alarm This way, you could have the device in two pieces: The electronics, even the size of a watch and the replaceable wire. This how it will work: You go out, choose the place to camp. Then you put some sticks on the ground forming a triangle, or square, depending on your needs. Then, place the wire around the points and connect to the screw type connectors on the device. Turn it on (this way it could be inside your tent). The wire could be like the one found on motors, isolated. Once an animal or person brakes the wire, the alarm sounds. The maximum covered area its given on how much wire you use. It will be a tiny device, remember transformers and motors hold LOTS of wire inside. Any comments?