Wrapping temperature sensors

One of the things we discussed last night at our Meetup was the our air quality sensors. We started out with four sensor three years ago, in locations around Hull. All the ones still in place are still working, but they have fallen foul of the recent heatwave.

The temperature sensors are wrapping round when the temperature gets above 40 degrees. To save space in each LoRa message the temperature data is restricted to a range of -24 to +40. This gives a range of 64 which can be expressed in six bits. As you can see above, this doesn’t work too well when things get really toasty.

I think we could use some cunning code to figure out what that temperature should be, even though it has wrapped around. However, the next version of the code is will need to be changed to handle these high temperatures that we are now seeing.