Hook up an infidel filament thickness sensor instead of runout sensor, free IO pins for (soft)I2C?

[BogusF]

Hi there,

I'm trying to include an infidel filament thickness sensor into my printer (e3s1 pro, f103 Chip) and wondering about how to do it properly, so somebody else might profit off my efforts. The connector for the runout sensor on the creality board has four pins, I'm assuming VCC, Gnd, Runout Signal and ???. Maybe another GPIO? infidel uses i2c so my idea was to take one of those soft i2c libraries and assign some unused pins to it, et voilà! ;)

pins_CREALITY_V4.h only assigns one pin for filament runout, what's going on with the other one? If that one isn't suitable, there's still the unused z-limit switch pin that should be available and accessible.

AFAIK, hardware i2c pins are being used by the display so that's not really an option.

The STM32f103 runs on 3.3V but I've read that many IO pins are 5V tolerant so that should work out.

Any advice would be greatly appreciated. :)