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Switch problem Answered

I have a question for the electronics gurus out there.
I have a circuit that I want to activate for a set length of time (I'm using a 555 timer for this) when a door is closed and not operate again until the door is opened and then closed again. 
I'm an electronics newbie.  The one-shot 555 circuits I have seen rely on using a momentary switch, but in this case the switch will remain closed as long as the door is so the circuit will remain active.  Are there switches available that will close and open while remaining fully depressed?  Or is there an equivalent circuit that will work with an ordinary momentary switch?
Two more things:  the door is very small so the solution must be small; also the circuit will run on batteries so the solution can't be a power drain.
Thanks in advance, I hope this makes sense to someone!

Kerry

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Jayefuu

7 years ago

A monostable is normally level triggered as you mentioned. The tutorial below shows you how to turn it edge triggered. Whether you want it rising or falling edge triggered depends on how your switch is set up.

http://www.kpsec.freeuk.com/555timer.htm#monostable

James

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number8wireJayefuu

Reply 7 years ago

That's great! It's exactly what I wanted. Thank you!