emonTH firmware

Can anyone advise where there is a firmware for the emonTH v2 that fully handles multi-DS18B20?

The version (v3.2.6) that I see up on github - GitHub - openenergymonitor/emonth2: emonTH V2 wireless temperature & humidity sensor with SI7021 sensor - contains the comment -

V3.2.6 - [30/9/21 - RW] Multiple external DS18B20 sensors accepted. No change to config file.

When I connect a single DS18B20 it is detected and reported back to emonCMS. When I attach a second one, it is detected by the emonTH, but is not reported back to emonCMS. See “2 DS18B20” below.

emonTH FW: V326
No EEPROM config
Int RFM…
RFM Started
Node: 24 Freq: 433MHz Network: 210
Int SI7021…
SI7021 Started, ID: 21
SI7021 t: 22.63
SI7021 h: 56.36
2 DS18B20
‘+++’ then [Enter] for RF config mode
(Arduino IDE Serial Monitor: make sure ‘Both NL & CR’ is selected)
waiting 5s…

Initial answer to my own question - I have previously (years back) modified the firmware and uploaded it to support something like 18 DS18B20s, based on some comments and suggestions from a post back in 2020 or earlier. It basically involves a loop based on the number of probes detected and building up a custom payload to be returned - and then modifying emonhub.conf to decode the custom payload.

I’m going to be plowing through the firmware myself so that I can add in/add back the functionality and I’m happy to contribute the code back to the repository, but before I do this . . . has someone already done it and uploaded it somewhere? I reckon there’s a good chance that someone has already solved this and has a working config.



Ugh, second answer to my own question - I see the firmware has a comment to the effect that -

NOTE: If the number of external temperature sensors is changed from 1, the 4 lines below: ‘names = …’,
‘datacodes = …’, ‘scales = …’ & ‘units = …’ must be changed to suit.
The maximum recommended is 4.

I’m going to try that now. Apologies for posting before fully checking, but I didn’t spot that bit.


Thanks very much for sharing that observation, @zag (no need for apologies as far as I am concerned!) - I just came across your post, having also missed that crucial little detail when I was last trying to set this up, only a month or so before you. I can now embark on my long-planned logging of flow and return temperatures across various things…