Summary Hi ! This is a 1st version of my filament sensor. I use those cheap infrared sensor from ebay. Overall, it's just a housing that goes around it, letting you pass the filament inside. You may add a part of PTFE inside for better result The PTFE tube may need to be trimmed to fit inside the sensor. Like that the only visible part between the IR will be 1.75mm Printed with a .25mm nozzle Maybe it's printable with a 0.4, didn't try it You will need 2x M3x10mm screw 2x M3 Nut