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.
Based on this proof-of-concept: https://www.youmagine.com/designs/filament-diameter-sensor
1 Block
1 Lever
preferably printed in PETG, ABS or ASA as PLA may creep significantly over time
1 SMT control board (populated)
or
1 THT control board + components (see Eagle files)
Suitable programmer for ATTiny85 (eg USBtinyISP)
1 SS495A linear hall effect sensor (or comparable) eg. http://go.toms3d.org/SS495
2 M3x8 screws (eg ISO 4762 M2x8)
1 3x24mm pin (eg DIN 7 3x24mm, for mating lever to the block)
1 3x16mm pin (eg DIN 7 3x16mm, for roller bearing in lever)
1 3x18mm pin (eg DIN 7 3x18mm, for idler bearing in block)
6 M3 threaded inserts
Pins may be replaced with screws or grubscrews, which may result in decreased precision
1 6x2mm magnet (eg N35) eg. http://go.toms3d.org/6x2magnet
4 623 bearings (preferably 623-2Z / 623-ZZ) eg. http://go.toms3d.org/623ABEC
1 Ballpoint pen spring (or other soft 4mm spring)
Short length of PTFE tube eg. http://go.toms3d.org/bowden
1 1.5mm drill bit
1 1.7mm or 1.8mm drill bit
1 2mm drill bit
Calipers for verifying drill bit shaft diameter
Drill bits may be replaced with similar diameters. Measured diameter is to be written to firmware lookup table.
Analog output is currently not enabled in infidel_release (I2C and FAULT pin only)
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.
All source files, Arduino code, Eagle files etc at https://toms3d.org/uploads/InFiDEL_202102.zip
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.
The author hasn't provided the model origin yet.