• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

5 Zone Alarm System

Status
Not open for further replies.
#21
have you tried holding a magnet near a reed switch to keep it closed while you open the door or window? I haven't but it would be interesting to find out.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
#22
oldtimer said:
have you tried holding a magnet near a reed switch to keep it closed while you open the door or window? I haven't but it would be interesting to find out.
You need to know exactly where the reed is hidden, and also which way round the existing magnet is - or you've got a 50% change of setting the alarm off when you apply your magnet!.
 
#23
Yes I know that Nigel but it is fairly easy to find the switch since it has its own magnet and the polarity can be found without operating the reed, I prefer to use plate to plate contacts not because of reed problem,I just thought of that, but because they're cheap and reliable. I was born in Sheffield and hiked around Derbyshire in my youth,durint war tha nose.
 
#25
Hi
I need detect a bell fault in a PIC alarm based project....

the circuit is a common npn transistor with collector pull to 12 volts and a diode to protect tehm from inverse emf coming from relay or bell....

thank you
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading

 
Top