For a hobbyist weather station project I am going to use a Raspberry Pi and a Si7021 temperature/humidity sensor. If possible, I want to use one of the available casings, and enclose my Pi and the sensor in the casing. Now I wonder how to minimize the measurement error.

So, where to place my my sensor best? What is the hottest part on a Raspberry Pi under light load? I guess the CPU, but maybe it could also be the USB for the power input?

These constraints apply:

  • headless mode, no monitor or USB use
  • LAN access
  • Casing is this, which has some holes in it Image: Casing to use
  • I intend the case to wall-mount
  • Model is a Raspberry Pi 2, Model B
  • As an indicator, the core temperature is typically around 42 to 44 degrees Celsius.


  • A FLIR camera would help of course, but I do not have access to one of those.
  • 4
    It does seem a bit pointless to have one within the case. You will just be measuring the temperature and humidity of your micro-climate. It will be unrelated to the outside environment.
    – joan
    Commented Jul 15, 2019 at 9:42

1 Answer 1


I used to measure temperature on the Raspberry under different load.

I remember if you used something on the USB port, or the ethernet, the chip driving USB and ethernet becomes hotter than the CPU.

(I have a 3B+) But this should be true on the 2B. Anyways, the differences will be very very tiny.

Try find an infrared thermometer if you want to be sure they are not very expensive and can do a lot in DIY project !

As said by@Joan :

If you put your sensors in the same case/box that the raspberry you bill be monitoring the raspberry ! You need to put theses sensor outside of the box in order to monitor weather. Your electronic protected in your external case, and the sensor out of it.

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