Low battery or dead devices domoticz mqtt

General
1

Hi,

I am looking for a node or flow to check the status of batteries and dead devices.

Somebody with a good solution? Or examples.

2

I can read the battery voltages of some devices using MQTT. Setting various values (Low, Warning or whatever) and comparing to the actual voltage, you can send a message, warning or otherwise, in my case via Telegram. (Or you could display values/warnings on a screen.)

3

Yes, but is there a way to read only dead devices and low battery? And not to configure every devices.

And then send an message.

4

You can't really read a dead device. So you need a way to tell if a device is alive, not dead.

Depending on the capabilities of the device you could

  • Ping it at intervals. If there is no response trigger your notification flow.
  • Have it send "heartbeat" messages at intervals. If the heartbeat stops, trigger your notification flow.
  • If the time elapsed since the last reading exceeds n seconds, trigger your notification flow.

If your device can measure it's own battery level, have it send that data as the heartbeat payload.

5

With MQTT it may be possible to use the LWT (Last Will and Testament).

1 Like
6

LWT is good yes.
By default Node-red will receive the "Offline" message 30 seconds after the device drops off the network.

It's basically the same as my heartbeat suggestion but built-in to MQTT.

2 Likes
7

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