The kit can be used to make a shed or room alarm. It is armed / disarmed by a hidden switch. Alarms are detected by a micro switch mounted onto a door. A timer provides an entry delay during which the system can be disarmed, whilst a separate timer silences the alarm after two minutes. Both of these timers are implemented via a 555 timer IC. The alarm can be further enhanced by using a simple key switch for arming / disarming or by adding a magnetic door contact to activate it. The board, battery pack & buzzer can be placed into a box designed by the student.

Requires x4 AA batteries, available separately.