Hi
TTN node that I built with Bluepill, rfm & platform.io: https://befinitiv.wordpress.com/2020/03/03/lorawan-node-with-bluepill-rfm95-platform-io/
In fact very similar to other projects posted here but so far I have not yet seen the bluepill,rfm,platformio combination floating around. Maybe it is of help to someone.
Best regards,
befi.