Future Emon developments - life beyond Atmega 328?

@TrystanLea @glyn.hudson

Is there any progress on using a more modern MCU to replace the AT328?

I haven’t looked at the ADC of the ESP32, but comments on the forum suggest it’s rubbish [TW#12287] ESP32 ADC accuracy · Issue #164 · espressif/esp-idf · GitHub

I believe others are looking at STM32, which appears to be a better option: STM32 Hardware Development
I haven’t had time read the whole thread yet, but from what I have seen it looks good.

I have an interest in 3 phase, as I have a 3PH supply and 2PH generation.

The reason I ask, 3 phase aside, is it seems there is a coming need for more CT’s in the system. I have a colleague at work is already monitoring: Supply, Generation, AC battery and EV charging.

From what I hear 3 phase charging are also gaining ground due to the need for fast charging and multiple EV households.


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This has mostly been resolved for some time. There are also newer chips beyond the base ESP32 where that non-linearity/accuracy was reported. I’d suggest looking at the ESP32-C3 or ESP32-S2 as a possible replacement for the aging 328.

I’ve just spent that last few hours reading though STM32 link (there are 391 posts!).

I think from my point of view the 9 CT prototype shown, looks of interest, But there have been no posts since July last year and the link to prototype PCBs in the shop is empty. So I’m not sure where the development has got to.


I was wondering just the other day if that project ever turned into a product. @danbates was the driving force behind that effort, but I’m not sure if he’s still around these parts?

Hello @chrissg6eui @dBC the work on the STM32 boards paused last year but will be resuming again this year. It is still our plan to upgrade to to the STM32 hardware in due course.

Thanks for the update, I’ll look forward to that.