I had a mechanical runout sensor on my Ender 5, but had a couple of breaks in the filament between the sensor and the extruder. So it wasn't doing me any good. It also couldn't detect a clog, and since I'm printing more with TPU (Ninjaflex) I wanted something that would allow me to clear the clog and keep me from wasting several hours and some expensive filament.

A friend sent me a copy of the sensor he was using, but I ordered the wrong bearings for the one he had. So I ended up making this file from scratch. I need the practice in Design spark anyways.

I've included the Designspark file, so you can tweak it however you'd like.

The mount is designed to allow you to mount it vertically or horizontally.

I printed the decoder in two parts. The wheel in ABS, and the base in TPU. You can print this in one piece in whatever filament you have lying around PLA should work. And put a rubber band around the base, or get a small balloon and slice across it to make a band to put over the base.

I designed the path just wide enough to squeeze a piece of bowden tube in, and then trimmed the inside with a razer blade, so the filament will have a narrow path and just enough was cut away for the encoder to press against it.

The cable that comes with the sensor is pretty short. But I was replacing a mechanical sensor on my ender, so I just used the one I already had. I did have to switch the ground and signal wires at one end.

The magnets are pretty strong, and you won't have any issues with the cover coming off.
Make sure when you press the magnets you pair two together, put them in the cover, and then with them mated press them into the case. If you get them in backwards the magnets will repel each other, and there's no way to get the magnets back out once they're pressed in.

Magnets to make cover quick disconnect (4 needed)

https://www.amazon.com/gp/product/B07873ZCY4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Bearing (1 needed)

https://www.amazon.com/gp/product/B07S1B3MS6/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Sensor (1 needed)

https://www.amazon.com/gp/product/B0719K9Z9R/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1

Pneumatic fittings (2 needed)

https://www.amazon.com/BIQU-Straight-Pneumatic-Connector-Extruder/dp/B01IB81IHG/ref=sr_1_6?dchild=1&keywords=pneumatic+fitting+for+bowden&qid=1620499139&sr=8-6

m3 x 6 screws 2 needed to secure sensor.

m3 nut 1 needed for mount.

2 m3 T nuts needed for mounting in v slots.

m3 x 12 screws 2 needed for mount.
Whatever length you need for your setup, I used 12mm.

You'll have to enable the optical sensor in Marlin (or whatever FW you're using)
You might have to play with the distance to get it sensitive enough to trigger when you have a clog, but not too sensitive that it has false hits.

https://marlinfw.org/docs/hardware/endstops.html

https://www.instructables.com/Configuring-Endstops-on-Ramps-14-with-Marlin-firmw/

EDIT: If you're using Marlin, and adding a motion sensor for the first time...

FILAMENT_RUNOUT_DISTANCE_MM gets set in your Configuration.h file
and you'll want to make sure FILAMENT_MOTION_SENSOR is defined.
But the EProm probably will have 0 stored for the distance. So you'll need to load the default values, or change the distance via your LCD.

Mine is triggering at just over 1mm, Seems to work well at 5mm, but I set it to 7mm in case I have any noise happening.

Good thing is that I have my load/unload distances and priming distance and speed down perfectly after all this testing.

Ender 5 Pro

No

No

200

20