Laser Filament Monitor housing with Switch for Duet

thingiverse

The Duet Laser Filament Monitor works well with most filaments, but some filaments don't work so great with it. It lets you connect an additional filament presence switch that can detect when there's no filament even when the laser sensor can't measure the filament movement because of how the filament is used and disabled. I've added a placeholder for a microswitch to the housing design so you can easily add one. I've also moved the distance from the filament center to the PCB up to 9mm, which seems to help make the measurements more accurate. To turn off the laser sensor and only use the switch, use the S0 parameter with the M591 command. Don't forget to set P6 to enable the switch - P5 is for the laser filament sensor without an additional switch. Note that this is for V1.7 of the PCB and there are some small changes in V2.0. Print the monitor with the inner sides (filament path) facing down. You'll need supports to hold up the switch housing. It takes 3 M3 screws and hex nuts for the case, plus 2 M2.5 screws for the switch.