Need to make an electronic Timer

Discussion in 'The Projects Forum' started by JasonP, Oct 19, 2009.

  1. JasonP

    Thread Starter New Member

    Oct 9, 2009
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    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
     
  2. t06afre

    AAC Fanatic!

    May 11, 2009
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    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.
     
  3. JasonP

    Thread Starter New Member

    Oct 9, 2009
    13
    0
    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.
     
  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    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.
     
  5. JasonP

    Thread Starter New Member

    Oct 9, 2009
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    Any schematics you put in the direction of ?
    Thanks
     
  6. Bernard

    AAC Fanatic!

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

    Thread Starter New Member

    Oct 9, 2009
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    A 1 hour timing would be fine
     
  8. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    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.
     
  9. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    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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