Mounting your ESP8266 or Monitoring Hardware in the CU


I received an early Christmas present from :santa: today.

They are 3D printed DIN rail mounts and in the coming days I will post up some photos of what we are going to do with them. Basically they are designed for holding Open Energy Monitor (OEM) hardware to the DIN rail in your consumer unit.

What I will say is do plenty of bench testing, of whatever system you have chosen, and don’t tunnel through to next door via the consumer unit to bury your hardware. Sods law dictates that as soon as you have buried the hardware you are going to have to dig it out again for some reason or other.

We have some OEM hardware that will benefit from the mounts but we are also planning to use them to fit our WeMos in the consumer unit. We just about have enough space for an ESP and an emonTx.

Fortunately we happen to have a spare DIN rail so we will do a mock up first, take some photos and then transfer to the DIN rail in the CU.

My wife is going to be pleased to see the back of the step ladders that have been propped up against our CU, in a narrow corridor, for the last 2 months.

Connecting a PeaceFair Pzem-004T to an Espressif ESP8266

As my wife points out on a regular basis I’m just like a kid.

Well this kid couldn’t wait until Christmas morning to play with his new toys.

So here you go. Just a mock up an “Uno clone” and Leonardo without their emonTx jackets etc.
Smart Meter DIN Rail Mount
Loving the toys, thanks :santa: they are excellent.

Note to self: make the pcb a few mm wider and then you don’t need to use the blue-tak.


Can we take the step ladders away now?


Soon dear, soon.


Just a quick update on the procedure we used to mount the ESPproMon Smart Meter bridge deep inside the Consumer Unit (CU). Remember don’t do this until you have completed your bench testing.

We found that the 3D printed DIN rail mounts are a perfect fit for one of the many NFC cards we have. If you don’t have any NFC cards your Amex credit card will do. Yes Arduino Uno’s and Leonardo’s are exactly the same width as your credit card.

So we chopped an NFC card in two, drilled a couple of holes in the card and bolted the PCB to the card. We then simply pushed the complete unit into the DIN rail mounting brackets.

Some weeks ago we swapped a mains powered door bell ON / OFF switch, directly above our consumer unit, for a socket with dual USB ports.

We used a dual USB port socket as the Open Energy Monitor emonTx shield requires a 9V AC - AC mains adaptor and two USB connections (one for the emonTx and one for the ESP8266). If you are just working with the PeaceFair Pzem-004 then a single USB port is sufficient.

If you look closely you can just see the tip of the aerial that’s attached to the RF transmitter peeping out to the right of the Pzem. We are quite fortunate that our Consumer Unit is almost exactly in the centre of our apartment so the RF signal is strong enough to control devices anywhere in the property. You will need to check the range based on the location of your Consumer Unit in relation to your RF controlled appliances and your WiFi router.

That’s why we say do plenty of bench testing and our ESP8266 has been balanced on a step ladder, beside the Consumer Unit, for the last couple of months during our extended “bench testing”.