DIY Interconnected Smoke Alarm Project - Completed with Code

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1

I have been working on getting my Kidde Interconnected 120v smoke alarms to report when they are in the alarm state. This was seemingly difficult until I came across the SM120X relay from Kidde which outputs a 120v switched supply when the alarm sounds. I connected a ESP8266 (Wemos D1 Mini) to this which sends a MQTT message as soon as the board boots (which is when the 120v supply is turned on).

You can read all of the information and find the code here: https://github.com/crippit/hass_smoke_alarm

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I’m going to update this to add that it works well. I’ve now had the opportunity to test it without deafening the family and the alert to my phone and to my Ecobee are triggered within a few seconds.

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Thanks for sharing your project, I have this on my todo list. Do you have any pictures of how you connected all the pieces and the finished product? I’ve read thru your description and sometimes a picture is worth a thousand words or in my case a thousand questions. Recently all my smoke detectors have died and it’s time to buy new. Thanks

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Unfortunately this is the only photo that I have. It was fairly simple however as there is no wiring involved with the Wemos. There is a wiring diagram which comes with the relay. Feel free to ask any questions.

It’s worth adding that my interwired smoke alarms were in my house when it was built and all of the wiring was pre existing.

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5

After studying your picture and your write up this is what I think I understand…

  1. hard wired the sm120 to your existing smoke alarm circuit
  2. cut the end off an extension cord and wired that to the other side of the sm120 (120 volts out)
  3. plug a phone charger with usb cable into extension cord (5 volts out)
  4. power the wemos from phone charger
  5. when the alarm goes off the sm120 powers up the extension to charger to wemos and the
    software send an mqtt command on boot

Do you have all this in an attic or basement?

Thanks again

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Yep you’ve got this right.

It’s all installed in the basement, but you could equally do this in an attic.

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Thanks for the reply…lol I have typical New Mexico house…No Attic…No Basement
The walls are made of adobe…when they build these homes the contractor carves a channel to run wires.

But all is not lost I think I can make this happen now that I understand what you did.

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Good luck! Let me know if you need any help

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hello guys,

Planning for same automation but my plan is hookup kidde relays to my alarm panel.

I currently have very old smoke detectors and will be replacing them with smoke & co combo units. Found kidde also sell seperate relays for smoke and co.
Next step is to run a 4 stranded wire from alarm panel to relays junction box. I have few zones available on my panel and will be configured for smoke and co.

My alarm panel is hooked up with HA so I get notification and also make my neighbor know something went off at my house.

will post all the details with pictures once I have everything installed.

Cheers!