Hi, Im really stuck and need some suggestion/advice!!
Im trying to get the temperature in the fridge by using a DS18B20 temp sensor connected via 3wires, +3,3v Ground and to a 8266Gpio pin defined as a Dallas hub with Esphome on a 8266.
The sensor data line is pulled up to 3.3v via a resistor according to the instructions on Esphome.io.
When the temp sensor i outside the fridge, it seems to be reading correct temperature but when measuring inside the fridge it varies periodically up and down from 5°C to 10°C. (See picture)
and yes, I have verified that the actual temperature is constantly at 5°C and I also tried another DS18B20 sensor with same result.
For me that looks like a normal temperature regulation sawtooth. The temperature inside rises slowly until a certain point where the climate compression is switched on an then rapidly fall down to the desired temperature.
Are you shure that your other measuring device is fast enough to show this stepping? Are you watching it over a long time, as you see temp is rising slowly.
I also use several of those sensors and have accurate readouts.
Yes you are right!! It was actually the fridge on/off temperature hysterisis.
I could confirm that today with another temp sensor.
Thanks a lot for your comments.