Need to make an electronic Timer

Thread Starter

JasonP

Joined Oct 9, 2009
13
Hi All,

I need to create an electronic timer that will run off 5 / 12v DC.

It needs to be much like those mains timers you get to switch lights on and off at a set time. I don't need granularity of days and weeks, just minutes and hours.

Can someone point in the direction of a kit that is out there that I can make or of a design that I can throw together.

Thanks
 

t06afre

Joined May 11, 2009
5,936
Perhaps a micro controller could be something. I will also not recommend using any hobbyist device connected to the mains without constant supervision. If you are a beginner do not do it at all.
 

Thread Starter

JasonP

Joined Oct 9, 2009
13
It won't be connected to the mains. I need it to run off 5 / 12v DC supply, to control a circuit up to 24v DC.
 

Bernard

Joined Aug 7, 2008
5,228
If you do not need to change settings often, an 11 stage stright binary counter on a socket strip, with a 555 clock works well. If 5 min. resolution is sufficient, number of stages can be reduced to 9, still to many for 4060 so go with 4040, 12 stage. decoded time sets a flip-flop, which turns on a solid state relay; off decoded time resets flip-flop. Decoded 24 hour resets counter.
 

Bernard

Joined Aug 7, 2008
5,228
How fine do you need the minutes, 1, 5 , 10 or 15 ?? Do you want seperate decoding for min. & hours ??
 

Bernard

Joined Aug 7, 2008
5,228
One of 24 hours it is. Relay selected will determine transistor & R3, may want to use a darlington tran.May be better gate selection ,but had pin-outs of these at fingertips. I'll be back Friday, got to go now.
 

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Bernard

Joined Aug 7, 2008
5,228
For just hours, this would make programing easy, for ON , one from 1-6 h, one from 1-4 of group of 6h.Kind'a like Navy 4 hour watches, but 6 h watches instead. Switches for reset & time set. Could add led's to outputs, see Bill Marsdens blog on chasers.
 

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