Can a humidity sensor be added to an EmonTx v3? I have an EmonTx installed in the garage, monitoring temperature and electricity use, and it would be helpful if it could monitor humidity too.
Not “out of the box” it can’t, there is no official provision for a humidity sensor either on the board or in the firmware.
You would not be able to use the SI7021 sensor used in the emonTH v2 since that uses I²C, the pins for which are used for other tasks on the emonTx (a4/d18 and a5/d19). You could use the DHT22’s though, all you would need is power, ground and a data pin direct to the MCU, all of which can be found on the 6way term block (assuming you are using those resources for other things that is).
Then you would need to edit a emontx sketch to include the dht22 code from an emonTh v1 sketch.
Thanks. I haven’t made any modifications to the Arduino sketches before, and it’s been ages since I tried tinkering with electronics.
I’ve ordered a cheap Arduino starter kit to play with before I try making any changes to the EmonTX - it’s been on my to-do list for ages anyway.