uno + emontx shield + esp8266

Anyone have this combination with uno + emontx + esp8266?

Welcome, Didier, to the OEM forum.

I cannot remember anyone asking about this combination, I am not an Arduino expert so I cannot say that it will work or that it will not. However, I think my colleague @borpin would suggest that you use a Raspberry Pi Zero W in place of the ESP8266.

You might like to look for posts here about using the Pi Zero W with our emonTx (not the Shield) - there have been several in the last few weeks.

What is the uno doing?

I’ve done this, I think fundamentally it’s okay. I had to do it when I blew the shield’s radio module!

If you mean the esp8266-mod in the shop then we’re on the same page.

There have been changes to the firmware since I did it a few years ago so I don’t know if there’d be a new problem to contend with, maybe… If there’s a problem, you could probably find a solution here.

Sitting under the emonTx Shield, I imagine. The thread topic is emonTx SHIELD. Unfortunately, Didier abbreviated it - and that’s a long-standing source of confusion, because the emonTx and the emonTx Shield are two quite different things.

I have no doubt it has been tried, Dan says he has tried it and I’m pretty sure there has been discussion on this before, so there might be info somewhere here on the forum. But aside from that there is little/no documentation.

The most important thing is to match your IO levels.

The Uno connected to the emonTx-shield runs at 5v where as a standard esp8266 (and Pi’s) run at 3.3v.

The shop supplied “Huzzah” esp8266 has 5v tolerant pins due to onboard level matching. So yes you can use a “huzzah esp8266” but other brands of esp8266 boards will need checking and any bare esp8266 (or Pi) will need additional correction to the line levels, predominantly the shields serial output pin (Tx to Rx line).

Trystan has previously modified an emonTx-shield for use with an STM32, also 3.3v so you can probably seek out that discussion and apply a similar mod for use with either a bare esp8266 or Pi.

As for the software side, since the FW runs on the Uno (not the shield kit) we cannot know what FW you are running, but would assume you are able to upload FW should you need to.

Of the original example sketches in the emontx-shield repo, many of them will output a space separated list of values which can be fed into emonhub (assuming you are running the emonSD?), there is no leading node id, but if you only have one serial device connected that is not an issue.

None of the default/example FW sketches output the EmonESP serial output needed specifically to run with the emonESP firmware, so to use the emonESP you will almost certainly need to change the FW on the Uno to output name:value pairs.

I missed that.

Been there, done that. :roll_eyes:

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yes -> Howto --emonTx - Shield ESPEASY and WEMOS R3 UNO you can apply it to uno and esp8266 just the wemos is so much easier as I also posted for uno emontx and esp8266 as well ( but I used esp8266 that have on board support for 5 volt wemos mini etc)

I think It’s worth also looking at using the new firmware used on the emonTx (non-shield!).
With the Shield’s jumpers JP1 on DIG10, and JP2 on DIG2, it should work.

emonESP would work on the esp module, and has a big update coming soon too by the looks of it.

Hi didier
I did something a bit similar with an emontx shield over an Arduino uno but I ran into memory size problems. I had to use another brand of Arduino. I think the uno has something like 2K of memory.