Home energy monitoring with 9 channels

Hello everyone!

I am trying to design an electricity monitoring system based on this wonderful project, using the EmonLibCM library. I want to monitor 9 channels with SCT-013-000 30A sensors and a module based on ZMPT101B. The collected data will be sent to a web application (Home Assistant) using esp32 or esp8266. Studying the documentation on the website and, in part, the forum, I stopped at 3 options, so please tell me which would be the best for me:

  1. to use 2 x ATMega328P 3.3V, one with 4 x CTs and 1 x ZMPT101B, the other with 5 x CTs. The ESP32 will collect the data via I2C. The obvious disadvantage is the 10 bit ADC and I don’t know if I will need another ZMPT101B module for the other mcu to calculate the power. Or can I use a single ZMPT101B module connected to 2 mcu?

  2. (I’m leaning towards this) to use 1 x AVR128DB48 using the emonTx v4 documentation. The advantages are obvious even to me, but I don’t know if a single mcu has enough computing power and frequency to monitor 9 channels with sufficient precision. Or maybe it would be better to opt for 2 x AVR128DB48, as in the previous option, the one with ATMega328P.

  3. (the least likely). To use ESP32/ESP8226 with 1x, 2x, 3x… as many external ADCs as needed, such as ADS1015.

Thank you for your time and advice!

Welcome, Valentin, to the OEM forum.

First, please use the editor that is part of the OEM website to write your post. If you use another editor and copy into here, the site thinks you are a spammer, and you will not see your post until someone releases it.

No, you will not need a second ZMPT101B if you use the same input circuit as the emonTx4

I think it has. If you use the “emonLibDB” library - which I hope will be released within a few weeks - you will be able to read about 40 sets of 10 ADC channels (1 Voltage + 9 Current) for each 50 Hz mains cycle.

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Ah, I’m sorry. I’m not a native English speaker and it was easier for me to use an external editor, but that’s not a problem, I’ll do it in the future.

I guess that this new library will be based on EmonLibCM, not the original EmonLib, right?

Thank you very much, Robert, for all your effort! Your message was very helpful.

Yes - it works on the same principle as emonLibCM, but the differences are big enough to mean that it will not directly replace emonLibCM, you will need to make a lot of changes to convert the sketch.

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