Author Topic: Add Carbon Monoxide sensor to GarageMote  (Read 252 times)

ssmall

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Add Carbon Monoxide sensor to GarageMote
« on: December 23, 2018, 05:46:15 PM »
I had some time to look into CO sensors to the GarageMote.  I found an article on Digi-Key That explains how these types of sensors work here: https://www.digikey.com/en/maker/projects/874229f4378346a7a0d86c28c5ca2850

From the article:

There are two basic types of electrochemical gas sensors, 2-electrode and 3-electrode. They both operate with the same basic principles. A gas diffuses into the sensor and makes its way to the working electrode. There it reacts with a catalyst and creates ions (charged molecules). Those ions move through the electrolyte (sometimes similar to battery acid) and again react at the counter electrode where the electrons are freed (or collected) to move through the circuit. Depending on the gas being reacted and the catalyst, those electrons can be flowing into or out of either electrode. Measuring this flow of electrons (current) we get an idea of how many particles are reacting per second, which gives us an idea of how many particles are there in the first place.

The CO sensors I found look to be 5V like the MQ-7.
MQ7: $6
Spec Sensors 110-102: $20 https://www.digikey.com/product-detail/en/spec-sensors-llc/110-102/1684-1000-ND/6136363
Amphenol SGX Sensortech MICS-6814: $17 https://www.mouser.com/ProductDetail/Amphenol-SGX-Sensortech/MICS-6814?qs=sGAEpiMZZMve4%2fbfQkoj%252bG2Nq%2fShK7sHeuDWL17FDFg%3d

The MICS-6814 can sense more that just CO

Not sure if any of these would work without extra circuitry and needing a 5v power supply.

Felix

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Re: Add Carbon Monoxide sensor to GarageMote
« Reply #1 on: December 24, 2018, 02:17:13 PM »
If you have a supply of 5V feeding the GarageMote, that should make things easy.
Once you go to 5V you need some level shifting for best practices.

I was thinking of making some kind of microphone/piezo based Mote that can listen/learn the beeps of such an alarm (smoke, CO etc). It then has its own battery, is low power, and you can attach it to any alarm in the home or garage (one should be sufficient for smoke for instance, if they are wired together in the house). How about that?

ssmall

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Re: Add Carbon Monoxide sensor to GarageMote
« Reply #2 on: December 26, 2018, 05:06:34 PM »
Felix, if I understand correctly I would need to have a CO detector in my garage, like a NightHawk, and the mote would detect the ear splitting alarm that goes off if it detects CO and then do something to alert me.  Is that about right?

Felix

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Re: Add Carbon Monoxide sensor to GarageMote
« Reply #3 on: December 26, 2018, 05:10:52 PM »
Right. That was my idea. That way you have something you can probably trust more than you own DIY solution, and a bit more modular.
But it's just an idea. Haven't done any R&D on this  ::)
Alternatively, maybe there's a way to tap into the CO sensor and trigger an alarm that way, more intrusive, less modular, but potentially longer battery life. I dont like this though, I like unintrusive solutions wherever possible.

ssmall

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Re: Add Carbon Monoxide sensor to GarageMote
« Reply #4 on: January 02, 2019, 07:09:50 PM »
I don't have a CO detector in the garage currently so that is why I thought to add one directly to a moteino.  I would need to find a place in the garage for the CO detector where it won't be destroyed by the kids.  ;)