This is an entire alarm system with 5 impartial zones appropriate for a small place of business or home environment. It uses just 3 CMOS ICs and includes a timed entry / exit zone, 4 fast zones and a panic howeverton. There are indicators for each zone a \"system armed\" indicator. The schematic is as practices:
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Circuit Notes
Each zone makes use of a generally closed contact. These can be micro changees or usual alarm contacts (usually reed switches). Suitable switches can also be bought from alarm shops and hid in door bodys, or window ledges.
Zone 1 is a timed zone which need to be used because the entry and exit point of the constructing. Zones 2 - 5 are fast zones, for you to trigger the alarm with out a delay. Some RF immunity is presentd for lengthy wiring runs by the input capacitors, C1-C5. C7 and R14 also kind a transient suppressor. The key change acts as the Set/Unset and Reset change. For just right security this must be the metallic kind with a key.
Operation
At change on, C6 will cost by approach of R11, this acts because the exit extend and that is set to round 30 2nds. This may also be altered through varying either C6 or R11. Once the timing length has elapsed, LED6 will mild, which implys the device is armed. LED6 could additionally be installed externally (at the bell box for example) and provides visual indication that the device has set. Once set any contact that opens will set off the alarm, including Zone 1. To stop set offing the alarm on entry to the constructing, the concealed re-entry change need to be functiond. This will discharge C6 and begin the entry timer. The re-entry change can be a hid reed swap, positioned anywhere in a door frame, however invisible to the attention. The panic swap, when pressed, will trigger the alarm when set. Relay contacts RLA1 provide the latch, RLA2 operate the siren or buzzer.
Zone 1 is a timed zone which need to be used because the entry and exit point of the constructing. Zones 2 - 5 are fast zones, for you to trigger the alarm with out a delay. Some RF immunity is presentd for lengthy wiring runs by the input capacitors, C1-C5. C7 and R14 also kind a transient suppressor. The key change acts as the Set/Unset and Reset change. For just right security this must be the metallic kind with a key.
Operation
At change on, C6 will cost by approach of R11, this acts because the exit extend and that is set to round 30 2nds. This may also be altered through varying either C6 or R11. Once the timing length has elapsed, LED6 will mild, which implys the device is armed. LED6 could additionally be installed externally (at the bell box for example) and provides visual indication that the device has set. Once set any contact that opens will set off the alarm, including Zone 1. To stop set offing the alarm on entry to the constructing, the concealed re-entry change need to be functiond. This will discharge C6 and begin the entry timer. The re-entry change can be a hid reed swap, positioned anywhere in a door frame, however invisible to the attention. The panic swap, when pressed, will trigger the alarm when set. Relay contacts RLA1 provide the latch, RLA2 operate the siren or buzzer.
Author : Andy Collinson
