Coffee maker fill device

Discussion in 'General Electronics Chat' started by alex3324, Feb 9, 2013.

  1. alex3324

    Thread Starter New Member

    Feb 9, 2013
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    0
    First post here, and I did conduct a search, but didn't find what I need. I want to build a device that, at the push of a momentary switch, energizes a time-delay device for approx 45 seconds which opens a solenoid valve and fills the fresh water reservoir on my coffee maker. When the time is up, the solenoid closes.

    I have the 12v solenoid valve and the SPST momentary switch.

    I also have an Omron H3Y-2 time delay relay. Spec sheet here: http://www.ia.omron.com/data_pdf/data_sheet/h3y_ds_e_4_2_csm92.pdf


    I am not sure this is the right time delay device for my job. I know power goes to pins 13- and 14+, but I'm not sure where the load (solenoid valve) connects, or how to wire the momentary switch. Does the switch cut the 12V+ lead on pin 14, or does it connect elsewhere? Do I even have the right relay for this job? Thanks for your assistance.
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    This shouldn't be run by time, as overflow is possible.

    You'll want a backup drain driven by a float switch if you do use a timer. The timer gives switch relay contacts between 12 and 8 on the right, or 9 and 5 on the left. 12-4 and 1-9 are the "normally closed" position, which is what is connected when the timer is "off".

    Otherwise, a feedback system to determine the water level and fill when empty only once, rather than keeping it full (and overflowing the coffee produced).

    There are a few ways to do the sensing, with a float with magnets and hall effect sensors on the outside, a mechanical linkage to float, or rangefinding from the lid, but the environment isn't friendly for electronics. Many or most solutions require logic or a microcontroller (some are far easier to use than one would think).
     
  3. BillO

    Well-Known Member

    Nov 24, 2008
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    136
    I agree with TOG an this. You need to use a float switch. Something like this is cheap and safe. I use them along with a $5 microcontroller in my well control system and in my fish tank to detect levels. They are made of polypropylene, the same plastic that things like food containers are made of.
     
  4. alex3324

    Thread Starter New Member

    Feb 9, 2013
    2
    0
    Thanks TOG and Bill O. Can you suggest a micro controller to accomplish this? The momentary switch is important, I want to push it and walk away, not have to hold the switch mashed until the flow shuts off.
     
  5. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Why use a limit switch? Why not just drill a hole an inch.from the top of the reservoir an run a drain line back to the sink?
     
  6. BillO

    Well-Known Member

    Nov 24, 2008
    985
    136
    Would work, but what's the fun in that?

    @alex3324 You could use a PICAXE 08M2. They are less than $3. You could probably do the whole thing for under $10.
     
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