Reading values from an optical reader

[JoergZ]

I'm using an optical reader which reads values from a smartmeter (ISKRA MT631). The reader (https://docs.wattwächter.de/wifi-usb/ Gen. 1) is flashed with Tasmota firmware and provides values in this structure:
```
Wattzähler/tele/SENSOR {"Time":"2026-08-20T11:38:14","MT631":{"E_in":5250,"Power":-4,"E_out":16177,"server_id":"0a0149534b00056e0be4"}}
```
where E_in are kWh used from grid, E_out are kWh uploaded to grid and Power is current power in W (negative values upload to grid and positive values consumption from grid).
I want to see this values in Domoticz webinterface. No specific domoticz/in topic is generated by device even when I set idx numbers on Domoticz site of Tasmota.

Bildschirmfoto vom 2026-08-20 12-01-18.png (67.51 KiB) Viewed 368 times

What do I have to do to see the values in Domoticz on Utility site?

[waltervl]

If you create a dummy Electric(Energy and Power) device in Domoticz and fill in the IDX of that device in Tasmota field IDX 4 it should work.

But better would be to create a dummy P1 smart meter device in Domoticz and fill in the IDX of that device in Tasmota field IDX 10

If Tasmota is using http api calls to send the data to Domoticz then you have to make sure the security settings in Domoticz are correct to receive them.

[imautohuttraeger]

I have a similar Tasmota device "Hichi"

https://sites.google.com/view/hichi-lesekopf/startseite

In order to receive the actual power, I have to use

Sensor idx 7 Voltage/PM2.5

So the naming is not corresponding here.

Maybe it is identical with your "WattWächter"

[JoergZ]

Thanks for your help! At least I got it working using (on Tasmota) Idx4 and Idx7 and in Domoticz sensor type Electric (instant and counter) for Idx 4 and a custom sensor type counter with axis kWh for Idx7. And two other activities were important: deactivating Homeassistant services with 'setoption19 0' and forcing Domoticz' MQTT topics with 'setoption130 1' both commands given at Tasmota console.

[imautohuttraeger]

Good to hear that!

I think which Tasmota IDX sents which data (power, import counter, export counter) is dependant on the script for the individual electricity meter that runs on the tasmota device. So your IDXs seem to be different from mine. I have actual power on IDX 7, but you have an energy consumption counter. But I am just a copy/paste guy an can't name it in detail. I remember that I also had to use a custom device for energy, because a utility device was not receiving data.

Meanwhile I am only transmitting actual power to Domoticz as I had a lot of trouble with import and export counter data. Because of this I am doing the energy counting via dzvents and then I transfer it via another script to a P1 meter.

[JoergZ]

I wrote an email to my dealer reporting issues and solution. Idk if they changed firmware or what version is on device actually. Maybe I get an answer.