This is a simple - easy to build - modular alarm system. When it's activated - it will sound the siren for a fixed length of time - and then switch off. So it won't annoy the neighbours. Its modular design lets you to add any number of Alarm Zones, Tamper Zones and Personal Attack Zones to your system.
This is a photograph of the Simple Two-Zone Expansion Module . One of the zones is triggered by normally-closed devices - such as magnetic reed switches and passive infra-red detectors. The second zone has an additional input for normally-open switches - such as pressure mats. You can add as many of these Two-Zone Modules as you like to the One Time Only Alarm.
Click here if you're new to constructing stripboard projects.