Ender 3 Optical Runout Sensor

The model of optical endstop sensor that I had didn't line up well in the original, so I moved the holes slightly and made it possible to insert a little PTFE tubing on both sides of the body to allow for a smooth entry of the filament.

To install I used a couple of m3x12 cap screws and did did the following:
1. Raise the gantry to the very top to make removal of the original screws easier
2. Remove the screws on either side of the lead screw behind the extruder
3. Use the original screws to fasten the optical sensor board into this sensor body
4. Slide the assembled sensor down the lead screw and fasten it with the cap screws
5. Route the cable through your cable chain and into the mainboard compartment or into the raspberry pi

This was remixed in openscad, so if you find that your sensor doesn't line up with the holes I would be glad to make any adjustments or supply the files for you.