Prusa i3 Mk3 Filament Sensor (FINDA) Mod

myminifactory

This is a prototype designed as a replacement for the Prusa i3 Mk3 optical filament sensor, utilizing a ball bearing and a PINDA sensor (or another inductive proximity sensor since I didn't have an extra PINDA sensor). This type of sensor remains robust like never before and isn't affected by filament color, shine, or transparency. However, it's worth noting that iron-filled filament can trigger the sensor falsely. As a result, you're free to make your extruder any desired color without being limited to just black. I don't own a Mk3 myself (I have a Mk2s), but I use a Mk3 at work almost every day. While the optical filament sensor is fantastic with some filaments, it can be uncooperative at times. This led me to designing this extruder modification based on the original Prusa R3 extruder files and influenced by the FINDA sensor setup in the MMU2.0. Since I don't have a Mk3 at work that I'm familiar with, I haven't been able to install the modification yet. However, a simple bolt-on sensor mod (which can be found here https://www.myminifactory.com/object/3d-print-83081) was used to test the operation of the sensor and bearing combo. The bearing moves along the Y axis as the extruder does not, so it won't move away from the sensor during normal printing conditions. I still need to complete the required firmware modifications to replace the optical sensor with this type of sensor. To install this modification, you'll require a 10-14mm m3 Socket cap screw, a 5.5mmx1.5mm square nut, an 8mm ball bearing, and of course a PINDA sensor. I hope Prusa will adopt a similar system in the future. Good luck with your printing!