I’m starting to think that it also might be the embedded heater? It seems like it needs to “warm up” as it says. But with extended use maybe it just gets too hot and the readings just rise and rise. I have left my running for weeks now and it climbed quickly at first and then slow climbed over time well above what the spec sheet said was possible. So maybe its a combo of the heater and the voltage level.
if you take a look at the data sheet even your readings are pushing the upper boundary nophead. Mine continued to climb well above 50k.
So that leaves a few possibilities:
- The firmware is borked and we need a crack at the C code or whatever is running it
- The Python wrapper for that library is interfacing with it wrong (very unlikely it just asks for the values and does some quick math)
- The voltage level is at typical Raspberry Pi levels at 5v and is setting the resistance values and voltage readings off (very likely)
- The heater is starting to cook off the chip over time because again it is running at a higher voltage than is recommended (very likely)
So if a combination of 1,3,and 4 or at least one or more of 3 and 4 end up being true then the math needs to change in the python wrapper to account for the higher voltage and we can’t run these things at long times because they will start to cook off the chip and it will read climbing constantly. It would need to be a “turn it on, let it warm up, take some readings, turn it off, let it cool, repeat” type of script.
Again, if anyone from Pimoroni can let use know if any of this is close to correct that would be awesome. When I get a chance I’ll try to get a voltage reading myself.