Help with DS18B20 sensors

ESPHome
1

I recently extended the cables on 2x DS18B20 sensors for my fridge/freezer ESP. I cut and soldered and extended by about roughly 1 meter, maybe 2 max.

Since doing so, I am getting very strange readings. The freezer is reporting only -1degree and the fridge is like -2degrees.

The fridge used to be around 3degrees, and the freezer was like -15degrees.

I am using the standard 4k7 pullup.
Is there any reason this could be happening. This is not a very big extension in the cable length.

Thanks

one_wire:
  - platform: gpio
    pin: D2

sensor:
  - platform: dallas_temp
    address: 0x8501215ccdb32e28
    name: "Freezer Tempreature"
    update_interval: 60s

  - platform: dallas_temp
    address: 0x7e01215ccaaf0728
    name: "Fridge Tempreature"
    update_interval: 60s
2

Try with 2.2k or even 1k pullups.
Strange anyway, I would expect errors instead wrong temperature…
Did you look at the log? Maybe it’s not updating sensor values because of errors…

3

What do the esphome logs for the device say?

4

Logs look normal to me.

[00:57:17][C][gpio.one_wire:020]: GPIO 1-wire bus:
[00:57:17][C][gpio.one_wire:021]:   Pin: GPIO4
[00:57:17][C][gpio.one_wire:080]:   Found devices:
[00:57:17][C][gpio.one_wire:082]:     0x8501215ccdb32e28 (DS18B20)
[00:57:17][C][gpio.one_wire:082]:     0x7e01215ccaaf0728 (DS18B20)
[00:57:17][C][dallas.temp.sensor:029]: Dallas Temperature Sensor:
[00:57:17][C][dallas.temp.sensor:034]:   Address: 0x8501215ccdb32e28 (DS18B20)
[00:57:17][C][dallas.temp.sensor:035]:   Resolution: 12 bits
[00:57:17][C][dallas.temp.sensor:036]:   Update Interval: 60.0s
[00:57:17][C][dallas.temp.sensor:029]: Dallas Temperature Sensor:
[00:57:17][C][dallas.temp.sensor:034]:   Address: 0x7e01215ccaaf0728 (DS18B20)
[00:57:17][C][dallas.temp.sensor:035]:   Resolution: 12 bits
[00:57:17][C][dallas.temp.sensor:036]:   Update Interval: 60.0s

[00:57:53][D][dallas.temp.sensor:054]: 'Fridge Tempreature': Got Temperature=-5.9°C
[00:57:53][D][sensor:093]: 'Fridge Tempreature': Sending state -5.87500 °C with 1 decimals of accuracy
[00:58:00][D][dallas.temp.sensor:054]: 'Freezer Tempreature': Got Temperature=-3.4°C
[00:58:00][D][sensor:093]: 'Freezer Tempreature': Sending state -3.37500 °C with 1 decimals of accuracy
5

I think this is actually a faulty fridge.

The fridge is freezing and the freezer is just frozen.

6

Did it go faulty after you drilled holes for the extended cables? :thinking:

7

No I did not end up drilling at all.

8

Swap the sensors and see how it looks like.
Note that you can’t locate the sensor in fridge to the body, there has to be good air cap between.
If your beers are getting frozen in fridge, you are confirmed. :wink: