The InFiDEL is a cheap (< $5) filament diameter sensor that can be calibrated to provide surprisingly precise filament diameter readings in real-time. While firmware support is currently sparse, the idea is to use the sensor to correct for filament diameter deviations while printing. ~~Assembly and Calibration~~ ~Mechanical assembly~ ~Calibration~ Flash board with infidel_calibration_release Connect a host via I2C (eg running Host_example) Insert each calibration drill bit shafts and replace the lookup table entries in infidel_release with your own measurements Measure the actual diameter of the shafts and fill second column Use the host's output *1000 to fill first column Finally, flash infidel_release with your values filled out Hub should now output exact diameter values Analog output is currently not enabled in infidel_release (I2C and FAULT pin only) ~~Firmware~~ Daniel has uploaded the firmware to Github: https://github.com/drspangle/infidel-sensor/ For now, this is the recommended repo to develop against if you want to contribute to the code. ~~License~~ The design files are published as-is, CC-0 / no rights reserved. Attribution when used would be nice, but is not required. I do not have the time or resources to support this project to the extent it deserves. If you find the design or concept useful, you're encouraged to take it into the direction you see fit and share your results.