How to get a cheap smart meter with real-time power consumption?

Hi, I want to have a smart meter, to watch my power consumption in real time. I want to buy a extra power meter behind thealready installed power meter.

Which one is the best solution for me?

I use knx, but this is rather expensive.

If you are also using z-wave, I can recommend the Fibaro FGWPE Wall Switch.
The device is able to show power consumption in real time.

I use a YouLess Datalogger:
I am very happy. Via very small php script and exec binding I have the real time power consumption.
Installation is very easy. It works for smart meters as well as ordinary Ferraris meters.
PS: Apps also available.

Does the meter installed by your power company have the flashing LED on it that pulses bases on power consumption?

Here is one.
It supported by this firmware for esp8266 and publish all data to mqtt.

If i install something to read out the power meter from my power company or i install a meter behind it with s0 outpoot, this will not be very accurate i think, because the s0-output is to less to make a very accurate power consumption meter.

I don´t want to only have one wall plug with power meter, i want to measure my whole house.

I will look to the links you all gave to me.

I can´t use the s0 output (optical output) of my energy meter given by the power company, because i have a photovoltaic on my roof, so i can´t measure the power consumption of my house while the sun is shining.

I only want to get real-time power consumption - so which power meter (smart meter) can i install for this?

There is a good knx smart meter from enertex - but it costs about 400 euro and that is to expensive for me.

Search for SDM120/220/630 meters on AliExpress.

Hi, can you explane, or maybe send me your config, how you read out the youless in openhab?

Hi, i’m using the youless meters as well, both for gas and electricity.

Using http://youless/a they respond with the following:


101361,693 kWh
2647 Watt
95% (±3%) 
OK (31)


1730,946 m3
0 l/u
51% (±0%) 

I’m using the following item configuration which with my locale setting ("." versus “,”) results in correct values without the fraction:

 * Youless Energy meters

Number TotalEnergyMeter         "Stromzähler gesamt [%,.3f kWh]"        <energy>        { http="<[*?([0-9]*?),.* kWh.*)]" }
Number CurrentEnergyMeter       "Stromzähler momentan [%,.0f Watt]"     <energy>        { http="<[*?([0-9]*?) Watt.*?)]" }
Number EnergyMeterSignal        "Stromzähler Signal [%.0f %%]"          <energy>        { http="<[*?([0-9]*?)%.*?)]" }

Number TotalGasMeter            "Gaszähler gesamt [%.3f m³]"            <gas>           { http="<[*?([0-9]*?),.* m3.*)]" }
Number CurrentGasMeter          "Gaszähler momentan [%.0f m³]"          <gas>           { http="<[*?([0-9]*?) l/u.*?)]" }
Number GasMeterSignal   "Gaszähler Signal [%.0f %%]"            <gas>           { http="<[*?([0-9]*?)%.*?)]" }

I didnt waste my time yet to figure out how to get the correct numbers including fractions though :slight_smile:

Here is cheap MODBUS Power Meter plus RS485 to TTL adapter with WiFi Wemos D1 mini and MQTT.
Can control all this parameters and publish to MQTT topic:

Voltage -Volts
Current -Amps
Active power -Watts
Apparent power -VA
Reactive power -VAr
Power factor
Frequency -Hz
Import active energy -kWh
Export active energy kWh
Import reactive energy -kvarh
Export reactive energy -kvarh
Total active energy -kWh
Total reactive energy -Kvarh

You need connect 2 wires from SDM120 to TTL adapter and 4 wires to Wemos D1 mini.
TTL VCC to Wemos 3.3
TTL TXD to Wemos D6
TTL RXD to Wemos D7
TTL GND to Wemos GND

Here is sketch for Wemos were you can setup your network settings:
sdm120wifi.pdf (48.0 KB)
Rename it to .zip

Thanks to


Connect eastron SDM220, SDM230, SDM630 to mqtt.

How to assemble here:

assembled unit here:

1 Like

Hi! I would like open this sketch: sdm120wifi.pdf, but failed. How can i do this?

Hi. Rename it to

Hi @merlok Here is English only forum. please translate your post.


installed unit:

mqtt tree:

Hello martiniman,
I try to repeat the transfer of data according to your sketch.
Here’s my connection using Wemos d1 mini and adapter rs-485.
TTL VCC to Wemos 3.3
TTL TXD2 to Wemos D8 - 15
TTL RXD2 to Wemos D7 - 13
TTL RE and DE together D6 -12
TTL GND to Wemos GND


my settings

Could you please post the modbus.cfg that you have used?
[image: Встроенное изображение 6]
It would be very useful for me …
Thanks in advance

Hi. Some miss understanding, my sketch not using modbus.cfg and not using modbus binding, it post all data to mqtt topic.
But if you connect sdm120-220 directly to USB-rs485 converter - look here

Please I need to get in touch with you to build 50,000 smart meters for an electric utility, please contact me