Timer 5 sec every 5h

Discussion in 'The Projects Forum' started by Terfysgol, Jun 22, 2016.

  1. Terfysgol

    Thread Starter New Member

    Jun 22, 2016
    1
    0
    Hello everyone,
    i'm looking for a circuit that close a contact (or power a relay) for 5 sec every 5h.
    The circuit is going to be placed in a very small and sneaky place so smaller is better.
    i surf the web and the forum but i couldn't find a circuit that can be used so i want to ask you some sort of suggestions about the materials needed and the circuit.
    Thanks a lot
    Terfysgol
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    5,991
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    How accurately must the circuit abide by 5 hours and by 5 seconds? Real time or 4.7 to 5.3 good enough? Something else?

    Once started, does it simply repeat forever?

    Will the circuit be battery or wall plug adapter?

    What is the coil voltage and current of the relay?
     
  3. dannyf

    Well-Known Member

    Sep 13, 2015
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    Learn to code a mcu -> piece of cake.
     
  4. Marley

    Member

    Apr 4, 2016
    142
    40
    If you want physically small then a micro-controller is the answer. Something like a PIC12C508A has everything you need inside including the oscillator. 8-pin DIP. Could be done with a crystal oscillator, cmos divider chain and some logic but will be many components, complex and big.
     
  5. crutschow

    Expert

    Mar 14, 2008
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    The simplest non-micro way would likely be to use a CD4060 circuit such as here.
     
  6. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Use a cd4060.
     
  7. crutschow

    Expert

    Mar 14, 2008
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    Maybe to do the delay program itself, but not to learn how to program an mcu. :rolleyes:
     
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  8. Roderick Young

    Member

    Feb 22, 2015
    408
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    How about a PICAXE 08M2?

    - No external oscillator needed.
    - Cheap.
    - 8-pin DIP
    - No need to code in assembly. Program in BASIC.
    - Development software is free.
    - They provide a sample 4 or 5 line program to flash an LED. That could be adjusted to do 5 seconds on every 5 hours.

    Downside: you need a serial port to program it. Either you need an old computer that has one, or need to buy a USB-to-serial converter (not too expensive on eBay).
     
  9. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    +1 for the PICAXE. :)

    Ken
     
  10. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    Lots of USB to serial converters don't work with PICAXE due to inverted logic; problem can be solved with a couple of transistor inverters. Or you can buy the AXE-027 USB programming cable for about $20.
     
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  11. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Roderick Young likes this.
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