Interconnected Smoke Alarms That Work with Home Assistant

LHoracio on 16/02/2025 - 12:41

I'm after alarm sensors that can warn of a house fire (whether by CO, smoke, heat or perhaps have a mixture of them around the place). Right now I have the cheapest Bunnings generic 9v battery smoke alarms, but I would prefer to upgrade to a more sophisticated kind that:

  • Can be integrated into Home Assistant so we can get alerts while away
  • Nevertheless have their own foolproof siren in case HA trigger doesn't work
  • an alarm in one triggers the rest in the house

If there's a good option available from overseas but it isn't certified to the Aus standard (AS 3786) then I'm still interested - I can use it in addition to the existing basic ones.

Anyone got something like this going already and knows where the parts can be had?

Electrical & Electronics Smoke Alarm

Comments

  • soan papdi on 16/02/2025 - 13:02
    +1

    Google Nest: https://www.home-assistant.io/integrations/nest/

    • twadds on 16/02/2025 - 15:29
      +1

      These have possibly been discontinued, google still list them but they've been out of stock everywhere for months.

  • bargaino on 16/02/2025 - 13:03
    +1

    Since you don't need to control the alarms, the simplest solution may be to just listen for the existing alarm.
    The same device can listen for glass breaking, and other alarms.

    I've seen Bunnings sell packs of interconnecting wifi alarms which use Tuya, so should work in HA.

    I got a cheap Tuya wifi smoke detector from Aliexpress to play with, but it does not seem to have any way to inter-connect.

  • Shame on 16/02/2025 - 14:30
    +1

    This listens for the alarm sounds https://www.amazon.com/Ecolink-Wireless-Detector-existing-FF…

    Amazon Alexa can also listen for alarm sounds and send a notification

  • Horacio on 16/02/2025 - 16:50

    Aha thank you, the listening approach seems like a simple solution that allows me to use locally sold interconnected but otherwise 'dumb' alarms. As long as I don't find the sensor is triggered while I'm listening to Venetian Snares.

  • Jimmhead on 16/02/2025 - 17:44
    +1

    Does anyone know if you can listen in to the interconnected alarms that use the 433MHz RF frequency to communicate the alarm to one another?

    • Shame on 16/02/2025 - 18:35
      +2

      It should be possible. Years ago I hooked up a 433Mhz receiver to an arduino to listen in to a cheap outdoor weather station from bunnings.

      You should be able to listen in to the signal using a software defined radio (SDR) USB dongle. The hard bit is decoding the signal. The weather station I had sent a message once per minute. The message was a series of long and short pulses to represent binary ones and zeros. The messages were in the format:
      preamble, device_ID, temperature, humidity

      The preamble is a series of 8 to 32 bits that are always the same so the receiver knows the message is for it (e.g 0000111100001111 - 4 zeros then 4 ones repeated a few times). The device_ID was one byte in case you had multiple weather stations or your neighbour had one as well. The temperature and humidity were 1 or 2 bytes long (I forget?).

      In your case I assume the signal will be:
      preamble, device_id, alarm_status

      If your lucky someone will have already documented the signal and posted it on github. If you're unluckly then you'll need to work it out yourself by attaching a wire to the transmitter signal input wire and then recording the signal using an oscilloscope or your computer's microphone port. Attaching a wire is a lot easier than using an SDR receiver as it eliminates noise from other devices broadcasting on 433MHz. Once you've worked out the signal you can then use the SDR to detect it and a bit of code to parse the message.

      See here https://community.home-assistant.io/t/reading-433mhz-rf-sign…

  • pscac001 on 16/02/2025 - 19:16
    +3

    If you are interested in a little bit of DIY, most of the brands specialising in fire alarms (Kidde, PSA, etc.) will have a relay module available. It will provide a dry-contact output which you can connect to an esphome device, or any of the various off the shelf buttons or sensors which have a reed switch that you replace with a couple of wires.

    • Horacio on 16/02/2025 - 20:22

      Thanks, will have a look to see if such alarms are a cheaper way to go - certainly should be more reliable trigger wise.

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