RUN light to power on timer

Discussion in 'The Projects Forum' started by blofish, Apr 2, 2012.

  1. blofish

    Thread Starter Member

    Jan 8, 2011
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    I have a Deep Freezer with a Power ON light and a Run light. The power light is on as long as AC power is supplied. The run light only comes on while its chilling. What I need is something to turn on a timer when the RUN light is on and shut it off when the light goes off. I know a photo cell would be needed. I don't want to open the thermostat housing to parallel with the run light, which I thought about doing, as it is in parallel with the compressor but inside the thermostat housing. One false move and I ruin the charge. Thanks in advance.
     
  2. CDRIVE

    Senior Member

    Jul 1, 2008
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    I don't think an intelligent reply can be given without details regarding the timer your using. Also keep in mind that you may have to shield the run light from ambient light and therefor obstruct view of it.
     
  3. wayneh

    Expert

    Sep 9, 2010
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    It's SO much simpler to sense the light's power-on signal than to rig up something to "see" the light - which, after all, can burn out. Are you sure there's no way to tap in?
     
  4. blofish

    Thread Starter Member

    Jan 8, 2011
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    I was thinking of an indoor timer. The one they use to turn lights on/off when your not home (120 VAC) . I would set the timer for 12a, and when the RUN light comes on it would turn the timer on and then off when the light would turn off. I wont have a load on the timer. I wanted to see how long my the deep freezer would per day. I've checked a few timers and most seem to be in the 4 Watt
     
  5. CDRIVE

    Senior Member

    Jul 1, 2008
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    What you're describing doesn't make much sense. You'd be better off with a device wood workers use to turn on their dust collector. It's an in-line module where a machine (like a table saw) is plugged into the module and the module is plugged into a receptacle. The module has an auxiliary receptacle on it that the dust collector plugs into. When the table saw is turned on there's a short delay of a few seconds, to minimize the surge of two machines firing up at once, but after that the auxiliary receptacle becomes live and turns on the dust collector.

    You could use this arrangement to plug in an analog 120V clock, that has no battery backup. These old style clocks run off a very small synchronous motor that only advances time when power is applied.

    I'm not sure what minimum current is required to trigger the device but it's worth investigating.
     
  6. CDRIVE

    Senior Member

    Jul 1, 2008
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  7. blofish

    Thread Starter Member

    Jan 8, 2011
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    CDRIVE
    If I used that device then it would be on all the time as the AC is on all the time for the deep freezer. As I mentioned, the ON light is on at all times. My goal here is to 'time', my RUN light is on only when the freezer comes on to freeze the food. This is why Im consintrating on the RUN light, as it only comes on when the frezer is cooling the food. The end result would be... When the RUN light comes on, the circuit will active a relay or SSR and turn the wall timer on Ill have it set (the wall timer) at 12 Midnight at 9am in the morning... Say it runs for 15 minutes... then it stops cooling and the RUN light goes off. In turn the timer will stop runing... now its at 12:15am. The next day at 9am I will see how many hours and minutes the freezer ran. I hope I explained it better. Thank you for your input
     
  8. CDRIVE

    Senior Member

    Jul 1, 2008
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    What is it that you think is running when the thermostat has turned off the compressor? As I see it, the only thing on (drawing current) will be your little power on light (that you said is always on) and that won't pull enough current to trip the device I posted.

    Edit: I'm guessing that your pilot light, if incandescent, is about a 1/4W lamp. At 120V that equates to only (.002083A) 2.083mA! Hardly enough juice to trigger that device.
     
    Last edited: Apr 3, 2012
    blofish likes this.
  9. GRNDPNDR

    Member

    Mar 1, 2012
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    Call me stupid but couldn't you just put and outlet on that light and plug a timer into that?

    that would just be two simple wire connections to an outlet.
     
    Last edited: Apr 3, 2012
  10. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Sounds like you want determine how much time the freezer is running each day. The idea of a photocell driving a small circuit that drives a small relay that stitches on a 120VAC clock would work. Or, the same circuit, without the relay, powering a 1.5v battery desk clock.

    Is that the concept?
     
  11. blofish

    Thread Starter Member

    Jan 8, 2011
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    Yes KMoffett thank you that is what I was thinking! If I can see how long my freezer is on I can even determine the RUNning cost... (time x E x I). Now that I looked around this fourm, I think if I use a photo cell to turn it on. Your 1.5 volt clock was a great ideal, cuts out the AC and could run of the same supply voltage. Could someone help with a schematic?
     
    Last edited: Apr 4, 2012
  12. blofish

    Thread Starter Member

    Jan 8, 2011
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    That light is in the housing with the thermostat, and I don't want to go there. the RUN light is in parallel with the compressor, tho that would work, I would have to go inside the housing.
     
  13. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    The photocell could be mounted on the outside of the case, covering the "run" lamp. That way it would detect when the lamp is on or off. Got a photo of the panel with the lamps?
    There tons of light detector circuits on the net. I don't have time right now to throw one together, but might later.

    Ken
     
  14. CDRIVE

    Senior Member

    Jul 1, 2008
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    It's Wednesday so I'm heading out to my watering hole. I thought I'd post this before I left. We'll discuss the particulars when I get back. The clock kit shown has been discussed here before. They're very, very, very inexpensive and easy to tap into. They're sold in craft supply stores, Internet and on ebay. These clocks draw very little and run off a 1.5V AA for > 2 years. Though I show a clock motor, it's used only for this sim. The clock module employs and oscillator and I doubt that it's actually a motor.
     
  15. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Like the super-simple circuit, but what if the RUN lamp is a neon...flashing at 120Hz. ;)

    Ken
     
  16. CDRIVE

    Senior Member

    Jul 1, 2008
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    Well Ken, we both know the answer to that. Now that you mention it the odds are very good. ;)

    Chris
     
  17. CDRIVE

    Senior Member

    Jul 1, 2008
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    You might be waiting a long time. :rolleyes::confused:
     
  18. Georacer

    Moderator

    Nov 25, 2009
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    He will wait no more - decimated.
     
  19. blofish

    Thread Starter Member

    Jan 8, 2011
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    I think it is a neon light. Does that matter?
     
  20. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Neon pilot lamps turn on and off 120 times a second. Pulsing a clock supply at that rate would likely cause problems. Adding a rectifier/capacitor would solve that...but it also might require bumping the battery supply to 3V and dropping that to 1.5V for the clock. A bit more complicated than CDRIVE's elegant circuit, but do-able.

    Ken
     
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