I have had an endless number of problems getting the STM32F103C “Blue Pill” microcontroller to work properly in the PipeWind pressure monitor. First I had problems getting the microcontrollers to work in the first place, which required actual hardware modifications to the microcontroller boards. Then there was figuring out how to install a working bootloader on the devices. Then getting the SoftWire libraries to work properly with our dual Bosch BMP280 pressure sensors. But finally it did begin to work.
That is, until some software update suddenly made it impossible to upload firmware to them. Whether it was changes in the Arduino IDE, the dfu-util or something else I do not know. And frankly, I no longer care. I was excited about these very powerful yet dirt cheap microcontrollers, but now I have wasted so much time getting them to work, that I never want to see them again.
The plan now is to replace the Blue Pill with an equally powerful but much more expensive Teensy 3.2. They always work like a charm, and there is no need for hardware hacking, cumbersome bootloader programmers or annoying software/bitbanging I2C libraries.
Maybe I should even try one of the new Teensy 4.0 microcontrollers. They run at 600 MHz with the same price tag as the 3.2. That’s just insane.