My Fridge (nevera) project! Help me to fix this nasty bug!

Hello,

This summer (2022) I created an ESP32 device to help my family use the fridge but there is a bug that is still not fixed and I don’t know how to fix.

I’ve created a Github repository here:

and a video here

The video shows the problem. It looks like the SPI communication is not stable. When the magnetic sensor transitions from off-on state (the door is closed) a kind of “interference” corrupts the SPI communication with the Max7219.

Actually I’ve tested the following things that are not the source of the problem.

  • 8 channel bi-directional logic level converter, unused lines are tied to GND
  • Adding capacitors to avoid power going down
  • Deep review of the code and the surrounding components

I need your help to understand what could be happening and how to fix it.

Thank you in advance!

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