I have a DS18B20 temperature sensor connected to a Raspberry Pi 3b+. I created a simple Python program to monitor the temperature of my heating system. The program works very well....when it works...sometimes it stops and when I check the raspberry pi, the sensor in /sys/bus/w1/devices is no longer there.

I noticed that the voltage between DQ and GND, when the sensor is correctly detected by the raspberry, is equal to 5V, while when it is not detected, the voltage drops to 1.3V. it's the only strange thing I've noticed and it persists even when changing raspberry and changing probe. I even changed the cable.

I have other 3 systems like this one that works perfeclty with the same configuration.

On the raspberry I use a board, this board https://sferalabs.cc/product/iono-pi-board/

  • 5V might fry Rpi. except is Rpi5.
    – tlfong01
    Jan 13 at 13:06
  • I have a board attached to the Rpi from sferalabs and the sensor is connected through the board. Notice that I have other 3 systems like this one that works perfeclty with the same configuration. Jan 13 at 15:34
  • The DS18B20 requires a pull-up resistor (between middle/data pin and Vin pin), is the resistor that you are using the same in all configuration? Jan 13 at 17:36
  • "I created a simple Python program" which you haven't listed. You posted vague comments about DQ but otherwise failed to explain what is connected or what Device Tree settings are used.
    – Milliways
    Jan 13 at 21:18
  • 1
    @Luca Scalvi, I vaguely remember that I had a similar problem, but that was 4 years ago. You might find the following answer useful: raspberrypi.stackexchange.com/questions/100203/…
    – tlfong01
    Jan 14 at 7:48

1 Answer 1


I'll do more testing but for now I'm pretty sure I've figured out the problem. The power supply. I assumed it was good since it was sold to me by the same company as the board. I changed the power supply and the problem no longer occurred. I knew it wasn't a python programming problem

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