Alarm Latch

846

14:32:44

For that guy that wanted an "alaram". When the trigger switch is closed, the transistors will latch on until the circuit is reset.  Could also use an scr. 

Switch can be anything, it just needs to put 5V into the latch.  Any switch will do; microswitches, Reed switch, two pieces of foil under a bump in your carpet.  Emitter from a photointerupter would also work.  or an ldr, or a microphone with a small amplifier. 

Send the output from the base of the NPN into a relay driver for your alarm siren, alarm lights, defence turrets etc

published 11 years ago

ally21

11 years ago

Will try implementing it..thanks

faceblast

11 years ago

if you use a decent scr you might even be able to drive your siren with it as well, much simpler

Sine_eyed

11 years ago

Good call @faceblast- that's the perfect little circuit for the job! It's simple, it's effective and it doesn't cost much (everything you need for this circuit and more can be found inside a vcr btw ;^D), what more could you ask for? Give it a shot @ally21, I'm sure you can piece this one together..

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