Filament Motion / Jam / run out sensor for Duet 2 Wifi

thingiverse

I wanted a filament sensor for my printer rebuild, but I decided to build my own instead of using an off-the-shelf variant. Most of those models are based on a microswitch and can't detect a clogged nozzle effectively. So, I designed this one, which went through six main variations and numerous minor tweaks before reaching its current version. I developed it with my Duet2Wifi, but it should work with any control board that uses a pulse-based filament monitor. Check out the sensor in action - https://youtu.be/K6a5W7tXkro You'll likely need a resin printer like the Anycubic Photon to print this as the tolerances are extremely tight. Due to the transparency of resin, I found that I had to paint the opto-cog to make it work properly. I used silver, but only because I happened to have some on hand. Besides the body, lid, and opto-cog, you'll need a small amount of hardware: 1x 20mm length of M3 threaded rod (I cut the head off a 25mm M3 bolt) 2 x 10mm 4 wide x 3mm hole bearings (£7 for 10) 1 x 18mm rubber disc (I got 4 on eBay for £3, or one from my local plumber's DIY store for £2!) 5 x M3, 8 to 10mm screws 1 x optical break sensor (around £2) Assembly is straightforward: 1. Screw the optical switch into place in the side of the body. 2. Attach the opto-cog onto the M3 bar. 3. Place the rubber disc on the other end. 4. Add a bearing to both ends. 5. Insert it into the slots in the body. 6. Secure the lid. The filament hole is designed for a tight fit and requires that the PTFE tubes are cut in a specific way. The first 6-7mm need to be trimmed down in half to expose the inside of the tube. This half-tube will slot all the way into the middle of the body. Once assembled, simply connect the sensor to the Duet Z0 end stop connector and add the following command to the end of the config-override.g file: M591 D0 P7 C"e0stop" S1 E50 L4 R50:150 That's it. Job done!