MT681 - Energy Meter

  • Hi,

    my electricity supplier swapped meters: we've now got a MT681 and I was forced to get rid of my old sensor.
    So far things seem to work okay-ish, but there are a few things I don't quite understand...

    I've adapted the current "EnergyMeterPulseSensor" example.
    The optical sensor is connected to a ESP32 which is doubling as a Gateway.

    These are "MyMessages":

    MyMessage wattMsg(CHILD_ID, V_WATT);
    MyMessage kWhMsg(CHILD_ID, V_KWH);

    The Sketch Info:

    sendSketchInfo(F("Energy Meter"), F("1.1"));

    B.t.w.: what's the "F" for? That didn't use to be there ... 🙂
    I then present the device to Domoticz:

    present(CHILD_ID, S_POWER);

    And in the loop I send my data:

    send(kWhMsg.set(kWh, 4));             // Send kWh value to gw
    send(wattMsg.set(Watt,0));            // Send watt value to gw

    "Watt" being the current usage, "kWh" the total consumption that was registrated by my fancy MT681
    since we received it.
    In Domoticz I get just one device: Type "general", Subtype "kWh". In the log I get a "Power Usage" graph
    and a block graph telling me the "Energy usage" during one hour. Is there a way to display the current energy
    counter state as well. I seem to remember that it used to show up somewhere...

    In the hardware section my gateway/sensor node has 7 children with curious values:
    How did that happen? I would expect to have three children there: S_Power, S_Custom and the S_Arduino_Node...

    S_Custom was an experiment to add a RSSI value (via "WiFi.RSSI()"). Didn't work though. I did get values for RSSI
    but couldn't figure out as what/how to send them to Domoticz. Any ideas here?

    Thanks everybody!

  • Mod

    The F things is for Flash. It is optional, but saves ram. Detailed information at

    For RSSI, take a look at

    I don't know about the children stuff.

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