7 day timer

Discussion in 'The Projects Forum' started by jack mcleod, May 21, 2008.

  1. jack mcleod

    Thread Starter Member

    Sep 4, 2007
    21
    0
    Would appreciate receiving a schematic for a 7 day OFF, 5 min. On, recycling timer. 120 v input & output.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    How accurate does it need to be? Is it OK if the 7 days vs 5 minutes is approximate, possibly losing or gaining a few hours a week?
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    We had a similar request several weeks ago. You can buy a digital timer with your specifications for under $10. Unless you hot to build one, it is hard to beat the price. They use a quartz clock with a battery, AC In, AC Out, minimum of 1 event, up to 14 events, makes and models too numerous to mention. Available in almost every dept and hardware store (Walmart, Target, Lowe's, Home Depot).

    This what your looking for? Look for a lamp and/or appliance timer, they'll be next to the mechanical units with synchronous motors (which go for $5 or so).
     
    Last edited: May 21, 2008
  4. jack mcleod

    Thread Starter Member

    Sep 4, 2007
    21
    0
    The timer can be out by a day and plus or minus 2 min. The timers locally are in incriments of 10-15 min. (not 5 min ) and often are day light controlled,or are not suitable for underground junction boxes. However this is a small town with a limited selection (no box stores).
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    What part of the world are you in? I don't need an address, just an idea.

    As I've said, you could build one, it will be a lot more expensive than buying premade. I'm not totally sure what you mean by box store, but even small towns have hardware stores, or lumber yards. I used to live in the country, long time ago.

    How set are you toward building one? Even the 5 minute increment timers can feed a second timer that drops the on time to 2 minutes. Another possibility is to modify something like a watch and use it's alarm to trigger an AC circuit.

    I estimate a minimum cost for a project like this is around $50 (probably more), and the parts for it will be as hard or harder to get than the timer I mentioned. Either way you're talking mail order if a local store doesn't have it, and again, there is a very good chance you can walk in and get what you need directly somewhere. The synchronous timers, the ones with the 5 minute window, will be next to the digital LCD models generally speaking.

    If you build a clock circuit then you will also have to allow for a home brew quartz oscillator (or equivalent) and battery backup. Doesn't do much good to have a precision circuit that needs reseting every time the power glitches. Even synchronous motor appliance timers will have this problem.

    Another idea that might or might not work, something that triggers off sunrise or sunset, no timer needed.

    If this is for something like a deer feeder you'll also need to mention it, as a lot of electronics have temperature requirements.
     
    Last edited: May 21, 2008
  6. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    If dont want the on wall plugged timers you can find panel mounted timers which suit better for industrial applications. They support many options like they change the on/off time automatically when we move from summer to winter or they can hold many different programs in their memory and other functions.
     
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