Need help- want to make motion sensor device that will turn off stove top

Discussion in 'Analog & Mixed-Signal Design' started by ju1234, Sep 15, 2018.

  1. ju1234

    Thread Starter New Member

    Sep 15, 2018
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    Hello, I need some guidance please. I can hook up wires together properly. That is all my electric/ eletronic ability is. But I want to do the following:

    I want to make motion sensor device to automatically turn off the stove top (220 volt electric) if there is no motion in kitchen.

    Here is my understanding of the project:

    I can perhaps use a regular motion sensor device of 110v or 220v or perhaps a 12-24v dc to drive the primary output (something like https://www.ebay.com/itm/IR-Infrare...m=112801343154&_trksid=p2047675.c100010.m2109).

    I need to take the output from this to actuate a 220v 30-40 amp relay switch that will turn the stove top circuit on/off (4 burners, total maximum watts load of 4K to 5K). I did not find any simple/cheap device already available to accomplish this.

    How do I need to hook up the circuit and what type of components will I need? I am thinking using a simple outdoor light motion sensor and a 30 amp relay that is normally used for Air conditioners.

    Thanks for the help.
     
  2. Reloadron

    Distinguished Member

    Jan 15, 2015
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    If I were to do this I would mount a motion sensor similar to this in the kitchen. I say similar to because they are made by a dozen or more manufacturers and can be had at any home improvement store. They also conveniently mount in any single gang wall box. They also in most offer a bypass switch. I would likely use a pair of solid state SSR (Solid State Relay) which uses 120 VAC control voltage and control it from the sensor. You can also use a contactor (relay) with a 120 VAC coil as long as it supports the current the stove requires at maximum.

    There is likely a half dozen way to do what you are looking to do. If using a pair of SSRs I would run with a known reputable brand name like Crydom for example but that comes at a cost verse fresh off the boat from China. So that depends on what you want to spend. What is the maximum current the stove will draw? How many Amp circuit breaker is it on and in the US I assume a dual breaker. I have no idea of your location? Anyway you have a basic nutshell of how I would likely go about it.

    If you are going to switch 30 to 40 Amps I would figure 50 Amp service so 50 AMP SSRs or 50 Amp contactor contact rating.

    Ron
     
    JohnInTX likes this.
  3. JohnInTX

    Moderator

    Jun 26, 2012
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    Agreed! I have installed that very switch in several locations. Works great and has range (sensitivity) and field of view adjustments. Info sheet attached.
     
  4. wayneh

    Expert

    Sep 9, 2010
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    I suppose this must be driven by safety considerations?

    One issue to consider that could be a negative is that this approach may turn the stove off, but it will turn it back on again whenever someone walks into the room. Or when a pet goes by, or a bug flies past the sensor. The pet and bug issues may be trivial since the burner will go off again soon, but having the burner come on could be a real problem for an unsuspecting human victim. No one expects a stove to turn itself on. So you may want to add a latch function that requires a human to reset it once it's turned off.

    My range has a computer that wouldn't like being turned off. It would only reset the clock and that's not a big deal, but a PITA. My range also has various timed cook options that wouldn't work with this scenario - I don't want to have to dance around in the kitchen for 4 hours while the turkey roasts. :eek:
     
  5. Reloadron

    Distinguished Member

    Jan 15, 2015
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    I could agree with that. Pretty much a matter of what the thread starter actually wants. They can pretty much have it however they wish with any safety features added. I have a CX-105 laying around here which is a 24 VDC sensor so we could use a 24 VDC supply and make a latching circuit requiring reset following a no occupancy shut off. Things just get a little more complex and expensive.

    Ron
     
  6. AnalogKid

    AAC Fanatic!

    Aug 1, 2013
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    Don't think so. My brother's reasonably new range comes up from a power outage with everything off.

    ak
     
  7. wayneh

    Expert

    Sep 9, 2010
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    It depends on the individual stove and the details of its controls. My stove's top burners use old-fashioned knobs and would come on when the power returned. The oven in the same stove is computer-controlled and of course would be off with a power reset.
     
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