Hi Trystan,
Thanks for the detailed reply, and sorry if my earlier post was a bit grumpy, I was just frustrated that I could not add the expansion board I wanted to right now - and lack of options for the future.
Reading it back it was not very objectively worded in places so I apologise for that.
I still believe a lower cost sensor option would be a great benefit for existing and future OEM customers, I know your producing in low volume and a single board design makes sense - but as you note £58 extra over a EmonTX4 is a pretty large jump that’s hard to swallow. I had forgotten to deduct the EmonVS when comparing, but I have a EmonVX mini which I think was cheaper than the full EMonVS? (no USB-C as its just a voltage reference for the EmonTX4).
With battery storage, EVSE, heat pump - lots of green energy tech would need a TX solution outside the main monitoring location at the CU.
I still really love EmonCMS and EmonPi, its been great over the years and the integration with other open source options is really helpful.
I did add up the other day what I had spent in total on my solution… and (inflation adjustment asides) I think if the sensors were more significanlty expensive it would be really hard to justify. You do need to cover your costs and make a profit though of course.