Soil Sensor 2.2 TMP112 precision

#1

I just started to code Tasmota support, starting with the temperature sensor. I don’t understand why its so much off though. From what I can tell, its around 4.5 °C off (compared to a calibrated high-precision thermometer). In the docs it says it should be ±0.5°C when not calibrated. Any ideas? I would rather not need to add some calibration parameters…

Cheers,
Andres

#2

Have you also tested with our source code? Is the temperature value ok with it?

#3

That is basically where I copied the algorithm from… But no, they (I bought two) show:

Sensor 1:

Requesting Temperature...
871.00
872.00
871.00
Soil Humidity:871.33
Temperature:27.62
WiFi Client connected

Sensor 2:

Requesting Temperature...
873.00
873.00
874.00
Soil Humidity:873.33
Temperature:24.94
WiFi Client connected

Whereas the real temperature is 23.1°C

#4

Please also test the sketch TMP112.ino. I just tested the sketch and it works fine

#5

hmm, it seems like the temperature is just going up from the correct value until to around +4.5°C during operation. I think it could be the heat radiation from the flasher. Sorry for the noise.

Cheers,
Andres

Calibrated: 24.2

Sensor 1:
Temperature in Farhenheit: 79.93 F
Temperature in Celsius: 26.62 C

Sensor 2:
Temperature in Celsius: 26.75 C
Temperature in Farhenheit: 80.15 F