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https://github.com/entorb/readout_mt681_electricity_meter

Read out electricity meter Iskra MT681 (Stromzähler)
https://github.com/entorb/readout_mt681_electricity_meter

arduino esp esp32 grafana hichi iskra mqtt mt681 python tasmota

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Read out electricity meter Iskra MT681 (Stromzähler)

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# Read out electricity meter Iskra MT681 (Stromzähler)



## Motivation



After installing 2 photovoltaic modules on my balcony (check out the [project documentation](https://entorb.net/wickie/Balkonkraftwerk)), my electricity provider unfortunately replaced my old electricity meter (that rotated backwards when PV production exceeded my consumption).



As the new meter has an optic interface, I decided to try to read it out to have at least some benefit of the replacement...



A [great documentation](https://ottelo.jimdofree.com/stromz%C3%A4hler-auslesen-tasmota/) (in German) on how to read out different electricity meters was my starting point.



## Hardware



My electricity meter is an Iskra eHZ-MT681-D4A52-K0p



For the readout I bought an [all-inclusive product](https://www.wispr-shop.de/produkt/wifi-ir-schreib-lesekopf-diy-set/) for 40€ at eBay. It bundles



* Hichi IR sensor

* micro controller ESP01S (Wi-Fi and MicroUSB power connector)

* pre-installed software Tasmota V13.3



So no Arduino programming and no soldering ;-)



## Setup



Following the manual of the sensor I performed these steps



* connect laptop to sensor's Wi-Fi

* enter my Wi-Fi credentials

* switch back to my Wi-Fi

* access sensor webinterface

* setup the electricity meter via console -> script (see below)

* activating the script

* -> data appears on the main page of the UI

* set Logging->TelePeriod to 15 for readout every 15s

* (optionally) configure access to my MQTT server



### Tasmota script for Iskra MT681-D4A52-K0p



* copied from [Tasmota documentation](https://tasmota.github.io/docs/Smart-Meter-Interface/#iskra-ehz-mt681-d4a52-k0p)

* skipping/commenting out the last line of the static Meter_id



```text

>D

>B

=>sensor53 r

>M 1

+1,3,s,0,9600,MT681

1,77070100010800ff@1000,Verbrauch,kWh,Total_in,4

1,77070100100700ff@1,Leistung,W,Power_cur,0

1,77070100020800ff@1000,Erzeugung,kWh,Total_out,4

; 1,77070100000009ff@#,Service ID,,Meter_id,0|

```



### Set timezone



see [doc](https://tasmota.github.io/docs/Commands/#control)

in webinterface open console to read and change the timezone

`TimeZone` show current timezone

`TimeZone 99` use timezone configured by TimeDst and TimeStd



[tasmotatimezone.com](https://tasmotatimezone.com/) provides more info, in my case it suggests this command

`Backlog Latitude 49.5928616; Longitude 11.0056; TimeDST 0,0,3,1,1,120; TimeSTD 0,0,10,1,1,60; TimeZone 99`



## Data visualization



### In device webinterface



[Here](https://ottelo.jimdofree.com/stromz%C3%A4hler-auslesen-tasmota/) is described, how to upload a Tasmota firmware and script, that provides data visualization on the webinterface of the device. I did not try that.



![Tasmota](images/tasmota.png "Tasmota")



### In Grafana



Instead, I use some existing pieces of software on a Raspberry Pi 3b "server".



* activate MQTT protocol in the sensor webinterface to send the data

* Python script to receive the data via MQTT

* InfluxDB to store the data

* Grafana to visualize the data



![Grafana](images/grafana.png "Grafana")



See [example_code](example_code) for Python example and Grafana dashboard model.



### In HomeAssistant



Alternative setup could be to use HomeAssistant to receive the data via MQTT, with is also described in the [HowTo](https://ottelo.jimdofree.com/stromz%C3%A4hler-auslesen-tasmota/).



## Tasmota commands via MQTT



see [Tasmota documentation](https://tasmota.github.io/docs/Commands/)



Sending an empty message body, results in the device responding with its current value.



```sh

mosquitto_pub -u mqtt_user -P mqtt_passwd -t "cmnd/tasmota_MT681/webserver" -m ""

```



## Power Saving



### Disable webinterface



After setting up the device and connecting to MQTT broker, I decided to turn off the webinterface, to hopefully reduce the power consumption. (here tasmota_MT681 is the name of my device)



```sh

mosquitto_pub -u mqtt_user -P mqtt_passwd -t "cmnd/tasmota_MT681/webserver" -m "0"

```



### Sending frequency



Reduce the devices sending frequency to every 300s



```sh

mosquitto_pub -u mqtt_user -P mqtt_passwd -t "cmnd/tasmota_MT681/TelePeriod" -m "300"

```



Since attaching the device to a power source, instead of a power bank (see below), I use 10s during the day and 30s in the night. Switching is triggered via crontab of my raspi.



### Sleep and Dynamic Sleep



see [Tasmota Energy-Saving docu](https://tasmota.github.io/docs/Energy-Saving/) on Sleep vs. Dynamic Sleep

(currently I use default Dynamic Sleep and 50ms)



set longer sleep time of 200ms (default is 50)



```sh

mosquitto_pub -u mqtt_user -P mqtt_passwd -t "cmnd/tasmota_MT681/Sleep" -m "200"

```



Switch from Dynamic Sleep (0) to normal Sleep (1)



```sh

mosquitto_pub -u mqtt_user -P mqtt_passwd -t "cmnd/tasmota_MT681/SetOption60" -m "1"

```



## Power Supply



Since I had no power plug in the meter cabinet available, I used an USB power bank. Unfortunately, that one only lasted for a couple of days, despite my power saving efforts. So I installed a 5V power source [MEAN WELL HDR-15-5](https://www.meanwell-web.com/en-gb/ac-dc-ultra-slim-din-rail-power-supply-input-range-hdr--15--5) behind a new fuse in the meter cabinet.