OpenEnergyMonitor Community

Problem with humidity reading on EmonTh v2

Tags: #<Tag:0x00007f1be3233178>


I have an emonTH outside the house in a birdbox and I have been taking external temperature and humidity readings for more than half a year now just fine. Recently I think however the humidity readings are starting to go wrong (temperature is fine though). I have a Nest in the house that measures the indoor humidity and I always see that the EmonTH sensor and the Nest are always going in the same diretion (about a 10%RH difference usually indoor and outdoor but sympathetic) so I know when the sensor is giving sensible numbers. Recently though I look at the data and I see a lot of readings at 600% and then 0%, and this week in particular it’s reading between 80-100% constantly when it should be around 70%.
Have I done something wrong or does it need calibration or is the humidity chip faulty?Any ideas on things I can try, like buying just a new humidity sensor and swapping it over…?

Corrosion on the sensor pins and socket has been reported in the past - it’s worth checking.

I think that only applies to the v1 with the dht22 sensor, the v2 has an SMD (can’t recall the part no offhand, the I2C part).

@SteffanCook, you could check the wmonhub log to see if there is any clues there, if you happen to notice a recent occurrence. What is the node definition in emonhub.conf for this device? Does it have a datacode or datacodes (singular or plural) entry?

Does the emonTx ever lose/drop packets or is it pretty regular at 60s intervals?

Will check over the weekend. Usually no packet loss until the battery dies. From looking at it there is no corrosion on the PCB board, everything still looks fresh.

I have just bought a new one. The new one is working fine back out in the birdbox and I will keep an eye out on it to see how long it lasts. They aren’t getting wet at all so I hope this one will last longer.

Old one has been put to use monitoring temperature of my cold water feed into the house (via temp probe attachment), where the humidity reading is not important.