Is there a device that...? (Need to monitor a gas stove.)

One way to find out If it will work. Sacrifice a contact sensor for the good of science. :slight_smile: I'm actually pretty excited about setting up some automations for this. I'm thinking about a motion sensor up inside the hood, so I can set some rules up for if no motion at the stove for x minutes and the burners are on...

Should be fun.

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Having left burners on myself you are on to something! Will have to think about it a little.. :thinking:

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This is nicely done! For this type of stove this is a good design. I have a italian cooktop with the knobs mounted on top and to the right. There his a good 4mm gap between the knobs and the metal base, and the knobs are solid. But I'm thinking of changing stove top the type you have so maybe I'll just wait for a bit and copy you.

I would setup the "things quited down" automation via a motion sensor for the kitchen as the way I would track if I forgot the burner. Maybe a virtual switch for an Alexa routine "Alexa start simmer" that when set functions to doubles the timeout in the warning automation.

If no motion by the stove fora 20 minutes and then a warning if no motion and maybe 40 minutes if the virtual switch is set to indicate simmer. Cancel the virtual switch when all burners on the stove are set to off so it returns to non-simmer mode

Neat stuff!

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Thanks! Yeah, I really did get lucky w/my stove configuration, suited my desired solution perfectly.

Decided I'm going to start w/a motion sensor on the kickboard on the island cabinets across from the stove. That will sense us walking around in that area and reduce false readings as it will be pointing away from the family room end of the room. I think I prefer to not use a sensor in the hood, as it might react to steam, and I'm concerned about it getting gummed up w/oil and particulates coming from our cooking, making it less sensitive/accurate.

Still thinking about visual notifications...want something that is noticeable, but not too obtrusive as we frequently make stocks and stews, and other dishes that may need to simmer for quite a while, and don't want the "burner on" lighting to become annoying. A fine line between safety and my wife saying "That is really annoying..." :wink:

Put a table lamp somewhere where you usually are and make it blink a couple of times? I prefer voice but yeah, that can get annoying. But then again getting my outdoor alexa to tell me I forgot something on the stove when I'm outside seems like a great idea.
I like the virtual switch method for telling the automation that I anticipate a long cook on the stove.

I agree with you, sensor in the hood is not a good idea. I find that putting the small lowes motion sensors on top of door frames makes them invisible. I have one on top of a frame that is pointing directly at the stove and away from the dining area. I use it as a temp sensor and as a sensor for hsm but it would be a good use for your use case.

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Just FYI, I just happen to work on a device that is powered from heat source.

I personally put temperature sensor above our stove.

I am looking for a way to come up with a better solution. Here is where I am today.

Let me know if you have any suggestion or request. It is a start for me. I can still adjust and make changes based on your input to my project.

Thanks
Iman

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Updated the thread title slightly to make it easier to find, since there were a lot of good/interesting ideas and approaches suggested.

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What temperature sensor did you use in your stove?

On the demo, I am using MCU temperature like most Zigbee sensor that give "free" temperature reading.

I have also used MAX31866 and MAX31856. They are thermocouple and pt100 rtd sensors. I am aware that with this hooked, It can double up as thermometer for your food. But, I am worry it can get too messy for gas stove. I am going to attached wither one for my Smoker to measure the internal temperature of my smoker.

If I can make it as small beacon, I am hopping that it can be tucked in some free area of the stove. The stove will send beacons when it is used.

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nicely done,

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Taking @Stephan.J's idea further, you should be able to use something like this: https://amzn.to/2MvfzBR
These are small thermocouples for propane grills, fairly low profile, you will need to figure out a way to attach them near the stove top. You can connect them to nodemcu or wemos board https://amzn.to/3b2t7ik - you may have to modify the code a little to work with it. @ogiewon may be able to give more guidance, ST_Anything with with nodemcu/wemos can literally solve any problem :slight_smile: - well almost.

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The elegant (and only) solution, in my house and according to my wife, is the solution you don't see at all. So thermocouples are not going to happen in our home. To quote the queen:

"OK, but only if the stove looks exactly the same when you're done."

So it shall be written, so it shall be done.

:wink:

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I hear you - LOL had a similar conversation with the wife a few mins ago. However I think it may ve doable. This is a sticker type almost flat thermocouple used on car exhaust manifolds. We could stick them to the underside of the burners, usually there is a massive void under the burners once you take the top off. However at 43 a pop, its a bit steep - however this means that if we can find a cheap high temp thermocouple we could take it to the bottom of the burner with a high heat tape or other bonding stuff you get for cars. We only need to get up to 700 C or so.

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This may work - https://amzn.to/3hFWpVu - these have tiny heads and rated to 700C. And this adhesive - https://amzn.to/2X5J6nF

I may try it out next time I get some time.
I really like the door sensor idea because it detects gas leakage as well, but my range design doesn't allow for that.

I can already see the doghouse that I would inhabit if I spent $250 on thermocouples... :slight_smile:

Yeah, I like the contact sensors because if the gas is on but not lit it still gives us a warning. This mod is one of the few that she likes so I will take that money to the bank. :smiley:

I am just starting to play around with ST_Anything with nodemcu integrated into hubitat, and a whole new world of being able to sensor practically anything and feed it into hubitat is appealing. If people have found a solution to this problem and are happy with their solution, that is great. HubDuino and nodemcu have a pretty steep learning curve and it is not for everyone. (I am still trying to wrap my head around parts of it, but as an old dog I like the challenge, LOL)

I have a few HubDuino projects that are more pressing than a gas stove sensor. But once I am done, I will put a CO2 sensor completely hidden in the range hood and wire the sensor (completely hidden) to a nodemcu esp8266 board. To me this has several advantages as a solution:

  1. mains powered, no batteries
  2. Replace the stove, sensor still works
  3. And most importantly, respecting the fire rating of the gas appliance. Anything installed inside a gas stove has to be fire rated. If you look at one of the solutions in this thread, where contact sensors where used behind the control panel, everything behind this control panel is high temp rated, including the wiring. I guarantee a battery powered plastic contact sensor is not. Having said this, everyone has their own comfort level with code compliance and each to their own.
  4. Cost, hard to believe how cheap a esp8266 board actually is, along with the sensors. I am currently working on 5 window sensors, one water meter reader, and one smoke/co integration. Bought everything I need for this project, including the window sensors for $25 CDN. I imagine in the USA the cost would be around 15 dollars. When I get around to the CO2 sensor in the range hood, I will probably still have room on the esp8266 board so the cost will only be the sensor, probably find one for 5-10 bucks.

The two links I posted above for the glue and sensors are fire rated and 17 bucks for 5. I am on the same page as you on everything inside being fire-rated - my plan was to mount the controller outside. I like the idea of adding a c02 sensor.
Now to find the time. I recently bought parts to build a depth sensor for salt in my water softener, but havent had time to look at it.

Just FYI, here are what I learn when I am working on my project. I am hoping the help everyone here before you purchase your thermal component.

Thermocouple and Thermopile is mixed heavily in here and in marketplaces such as Amazon, Ebay, etc. To me they are different. The fundamental working of Thermocouple and Thermopile is exactly the same. Thermocouple generate mili/micro volt depending on the heat applied to it. Measuring the mili/micro volt with amplifier+adc can be used to calculate temperature applied to the probe. I am not aware any electronic design that can boost this small voltage today to be used to power an MCU. Thermocouple mostly use as temperature measurement device.

Thermopile takes many cells of thermocouple and put them in series. They are put in series such that it can generate much higher voltage. It seems today the availability of thermophile that generate 750 mili-Volt is abundant. I think probably because of the application in fireplace. Thermopile is not used to measure temperature in general. Keep in mind that 750mili-Volt is not enough to power any modern MCU as is. In addition, the current generated is very small. In another word, the power generated (P=IxV) is very small. Additional circuit and power saving strategy is needed to use the common thermopile. Having said that, thermopile is used as power generation. It is unlikely used as temperature measurement.

Unfortunately, many vendors advertise one while actually they are selling the other one. Please be careful and ask question to your vendor when you are buying either thermopile or thermocouple. It depend on what you want to do. If you want to detect your gas stove by measuring the temperature, you would get a thermocouple. You have to manage your power supply either by battery or DC power.

I personally use thermopile to power a device that I am working for so that I do not need to deal with battery or routing a DC supply.

There is also a "rod flame" sensor(not IR based). The rod becomes a diode when it is exposed to flame. It is act as open circuit when there is no fire. An AC voltage (high voltage, very small current) need to be applied to the rod. When flame is detected, because it become a diode (with proper electronic design called diode rectifier), it can convert that AC voltage to DC voltage. There should be a circuit that would detect this DC voltage to determine whether flame is detected.

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No one here is talking about powering an arduino/nodemcu board with a thermocouple. But rather just having the arduino/nodemcu board read the milli voltage (temperature) and have this sent to hubitat. An ad595 is a electronic device that is designed for this purpose.

How about MAX6675 instead of AD595? seems to be much cheaper.