Filament Sensor

thingiverse

Having failed a few times at catching my printer before it runs out of filament, I finally decided to do something about it. I found the "Filament Sensor"-plugin for octoprint, and decided to use a microswitch to do the detection for me. This is the result; It is attached right before my extruder, so I can use almost every last scrap of filament I have laying around. Edit: Previous problems with rpi not booting was due to me brainfarting and connecting 3v3 and gnd with the 1k resistor between them. Somehow it still worked, but rpi did not boot. After wiring as described, it works as intended How I Designed This Stuff I had laying about So I have a lot of electronics crap laying around, so I figured I could use some of it for this. Among the crap, I have: Many meters of thin cable-strips Microswitches Resistors of varying values Dupont connectors 3D Design What I did here was basicly to model a very rough model of the microswitches I planned on using, Then I made the holder around it. The lever on the switch needed a little kink to make it pick up a better signal, which is completely OK by me. Circuits.io didn't have a Rpi model, so strech your imagination here Circuit To connect a button to the rpi3, I had to make a small circuit to avoid screwing it up. Basicly you need a current-limiting resistor (R1) on your input-pin, so you don't ruin your rpi. Then you need a pull-down (R2) to make the pin LOW by default. Then you need to connect one lead from the switch between the resistors, and the other on a 3.3v supply. IMPORTANT: Don't use 5v, as apparently the rpi doesn't like that! I used a Pin-out I found on google to figure out what pins were GND av 3.3v on the rpi, and chose GPIO 21 for the input signal. If you can't figure out how this should map over to your rpi, you might not want to do this... R1: 1k R2: 10k