This short collection of projects - some useful, some instructive, and some amusing - can be made for around 10 UK pounds (16 US dollars). The estimated cost does not include an enclosure (box). All of the projects are battery powered, so are safe to build.

This versatile and portable project guards your property by sounding an alarm whenever it is disturbed. Place it on top of your TV set and the alarm will go off if anyone tries to remove either the TV set or the detector. Put it in the saddlebag of your bicycle and it will warn others if any attempt is made to move the bike. Place it on the floor inside a closed door and the alarm will sound if anyone opens the door and disturbs it. There are very many ways to use this electronic Vibration Alarm guard-dog.