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Help me start designing a pulse switch

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Newbie level 2
Nov 6, 2007
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Hi all, first post, probably in the wrong place but this seemed the best place..

what i actually want is this (but its in the states and i'm in the uk, it'd turn out very expensive to ship it over, a total of $40 probably)

But it strikes me it must be pretty straightforward to make one

I takes a 1second pulse from a 12-14v source and this switches on the output to fog lights for example.. a shorter pulse switches it off.. but a constant input has no effect

(so useing the high beam you can switch on/off a device but unless you use a quick/slow pulse it does nothing)

Any ideas? could anyone help with a basic circuit design and ideas of the sort of components needed?

Thanks for reading

Pulse switch?

Hi man,
You can interrupts of Microcontroller like PIC 16F84 (5 $ ii think). In rising edge of the pulse Timer is started.
If fall edge cams before 1 second switch,
if fall edge comes between (1-s) and (1+s) then swich off where s is the marge of sensibility that you can chose.

Hope it help
Don't forget to push the helped me button.


    Points: 2
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Re: Pulse switch?

Hi, thanks for the reply

I'm afraid I'm not massively experienced with electronics although i just about grasp what your saying.

How would it look? or which pins should i have connected to what?

I'm aiming for something as small and as cheap as possible that can be sealed in resin or similar

Thanks again

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