Spotting Fake BMP280 Sensors
This is the story of three batches of sensors on breakout boards that I ordered over the last few years from AliExpress. All three batches where marketed as BMP280 chips on breakout boards.
The first and third batch worked fine, but the second batch appears to be fake, non-functioning sensors. Judging from a few internet searches there seems to be a fairly common issue of sellers trying to essentially re-label cheaper BME280 sensors as BMP280 since they look similar.
However in my case the sensors did not work and I wasted a lot of time figuring out that the sensors, not the other components in my project where the issue.
So, to hopefully safe someone else some debugging time I’ve added a closeup picture comparison of the fake and of the working sensors below of this post.
The fake sensor (that looks more like a BME280) would just respond to all i2c addresses and then behave badly enough that both micro controllers that I tried ended up crashing upon readout. (Which made debugging harder.)