RC snubber for relays module

Other Hardware General Electronics
33

Then there is indeed a voltage mismatch on the I2C bus.

  • The STM32 processor is 3.3V (there is a LDO voltage regulator on the Blue Pill to make 3.3V from 5V).
  • The SHT31 sensor is 2.15 to 5.5V, but its I2C bus must match its power.
  • The display is 5V.

The display is the odd one. It is expecting a 5V I2C bus, but it only gets 3.3V levels for SDA and SCL.
The display seems to have 4k7 pullup resistors that try to pull SDA and SCL towards 5V, possibly damaging the processor.

I would not expect this to run reliable for 1 minute. Regardless if this is the cause of your problem or not, you have to fix the I2C bus. A level shifter for the display is enough to fix it, but a level shifter also makes the signal a little weaker.

@anon35827816 it is a 3.3V system because of the STM32 processor (the sensor can do both).