5 Zone Alarm System

Posted on May 21, 2012

This is a complete alarm system with 5 independent zones suitable for a small office or home environment. It uses just 3 CMOS IC`s and features a timed entry / exit zone, 4 immediate zones and a panic button. There are indicators for each zone a `system armed` indicator. Each zone uses a normally closed contact. These can be micro switches or standard alarm contacts (usually reed switches). Suitable switches can be bought from alarm shops and concealed in door frames, or window ledges. Zone 1 is a timed zone which must be used as the entry and exit point of the building. Zones 2 - 5 are immediate zones, which will trigger the alarm with no delay. Some RF immunity is provided for long wiring runs by the input capacitors, C1-C5. C7 and R14 also form a transient suppresser. The key switch acts as the Set/Unset and Reset switch. For good security this should be the metal type with a key.

5 Zone Alarm System
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At switch on, C6 will charge via R11, this acts as the exit delay and is set to around 30 seconds. This can be altered by varying either C6 or R11. Once the timing period has elapsed, LED6 will light, meaning the system is armed. LED6 may be mounted exter

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