What's happened to emonTx V4?

@awjlogan Sorry - one more (rather late!) comment -

Looking again at the picture of the emonPi3, I see that it has screw terminal blocks. I’m guessing these will need the case to be removed to allow access to the clamping screws, which is not very convenient. Also if you need to move an installed emonPi3 for any reason, you have to work out again which wire goes into which terminal.

I much prefer the plug-in terminal blocks used on the emonTx4, as they don’t have these problems, although they add a little to the cost. And they may make testing the emonPi3 easier/quicker - no need for loose wires for the terminal blocks?

Any thoughts?

@rupert I think those screw terminals are just in the render for convenience, the actual part used will be the plug in type used on the emonTx4 and emonPi2 :slight_smile:

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That’s good :grinning: Thanks for the update.

Yes, as @TrystanLea said, just for rendering purposes - I’ll see if I can find the correct STEP file, it would be better.

@Gwil - managed to find space for a single mounting hole for the OLED display. Needed to rearrange a few tracks and fills, but nothing too drastic! It’s in commit 9e6175c. Unfortunately the other 3 holes completely overlap something solid, but it should provide a bit of extra stability.

That’s brilliant. IMO, one mounting point is more than enough.

First board brought up, found a few things that need to be changed (some alignment and spacing issues) :slight_smile: Further news soon!


Looking good :blush:

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If an ESP is used (on the serial pins) then I suspect one of the buttons will be inaccessible. Might have missed it, but there seem to be 2 ‘reset’ buttons?

Hi Brian - the bottom (as viewed) button (SW2) is an optional “user” button for anything that might come up in future, or you want to add yourself - the reset button is the top one (you can just see RESET on the silkscreen). There’s an additional couple of LEDs there (LED3+4) for general user defined purposes. I suspect they will not be useful for the emonPi3 in the current case anyway as it will be covered by the case and I doubt there’ll be a respin of the case as it’s expensive as is.

For the ESP module, I’ve got a little design that slots underneath (same as the Pi) and extends out at the same point as the Pi’s USB/ethernet. I think before getting too far down this route, a suitable case should be found - that’s always the start as PCBA is much cheaper than small volume case production. Ideally, it would be plastic so the WiFi will propagate. A metal case means extending the antenna outside the case, realistically. I’ll have a look for cases as well.


A little AVR-DB hardware update: We are gearing up to having the emonTx5 unit and 12 CT option (which can be applied to the emonPi2 or the emonTx5) available in the shop. The ETA should be by the end of the month / early May.

(pink: cutout area :grin: )


Have you sorted out that pesky problem with the precision reference?

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We are still on the first batch of emonpi2 boards, the emontx5 will be using current stock. I need to do the repeated test over multiple boards that you recommended.

If there is time, do you think there might be some space to punch out a hole for an LED indicator on the non-CT panel? There’s obviously not a huge amount of space, but it might be possible to squeeze something next to the SMA connector and pulse/temperature sensors. Useful for a powered on sanity check, if nothing else.

This batch of fascias is already in production but we could certainly make that change for a future version

:+1: I’ll have a look at it - it would fit nicely next to the SMA connector, but would be an additional single BoM line for a right angle LED. With no firmware running, there isn’t any indication that it is alive!

And the new fascias look excellent :slight_smile:

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I know I’m a small sample size but I also would be interested in buying an emonTx4. I bought a EmonPi and a emonTx back in 2021. I want to add more monitoring probes to the 4 I have now.
I understand the option of getting the EmonPi2 without an RPi but as you mentioned it is a costly option.
I looked back in my order history from 2021 and my EmonTx was not listed as a “EmonTx4” it simply was just called “EmonTx”. Was the Tx different back then or did I still get the same EmonTx4 that was discussed in this thread?

Last question, you mentioned about having a 6CT add on board to the EmonTx4, is that something I can utilize in my setup or would I need to buy a second EmonTx4 if/when you guys have that option available again?

If you bought an EmonTX in 2021 it will be an EmonTX3 (with 4* CT, one of which is limited to lower power).

The EmonTX4 was only released in Nov 2022, I bought one as soon as they went up on the shop as I recall.


EmonTX3 Manual


EmonTX4 Manual

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Good information. It is most definitely a TX3 then. I assume there are no expansion boards which means I am still dependent on them releasing a new TX4 option with the cheaper housing like proposed.


As Robert said no expansion on TX3.

You could post a wanted in the buy/sell forum but I think the TX are in demand due to them not being available from the shop, I think someone was asking recently with no answer - but always worth a try?