“It works as advertised, except for the fact that it gets heated by the USB port, measuring temperatures 3 celsius hotter and humidities 5% drier than the reality. This fact is not advertised and I don't see any easy way out of it. As the difference is not stable and not linear, arithmetic will not save you.”
“I purchased the "Adafruit SHT45 Trinkey - USB Temperature and Humidity Sensor" from Pimoroni on 23-12-2024.
Positives:
It comes out the box, working and sending back the temp, humidity etc. in CSV format across the serial port. One can also program it with circuit python to output in any format one wishes.
Negatives:
The temp sensing is pretty good, but the humidity sensing is very dependent on where you place the sensor. If its in still air it has one reading, if its in an air flow / draft, it reads something else.
What this means is that if you leave it in one place, it generally reads quite well and consistently, but move it and the readings all change. i.e. 50% one position, 55% the next second in a different position.
There is also a "heater" on the device, that one apparently needs to turn on once in a while to "outgas" any impurities it might have picked up over time.
My take away from this, is that accurate humidity sensing is actually pretty difficult to get right.
Summary: it works, you just need to be very careful where you put it.”
