Simple Filament Run Out Sensor

thingiverse

SIMPLE FILAMENT RUN OUT SENSOR\r\n\r\n14.12.18\r\nUpdate - already!\r\nI built a 2020 mount for this sensor. It suits my setup using a titan-like extruder; it may suit yours too or be the basis for your own version.\r\n\r\nDon't you hate it when you've checked on a long print only to find the machine ran out of filament about three-fourths of the way through but just kept going?\r\n\r\nMost printer firmwares have the option to pause and give a warning if filament is running low, but few printers come with the necessary sensor. There are plenty available, both here on thingiverse and commercially, so why another? \r\n\r\nI think this version is as simple, cheap, and easy to print and set up as you'll find.\r\n\r\nYou will need:\r\n- Basic soldering skills\r\n-A printout of the runout_sensor_parts.stl\r\n-A 5mm tact switch\r\n-Super glue or similar\r\n-Some suitable wire\r\n-You can probably salvage both from an old device if you're feeling cheap.\r\n\r\nYou will also need a way to activate run-out sensing in your firmware and know where to hook the sensor up to your driver board. Google will be your friend if the printer manual doesn't help.\r\n\r\nThe build:\r\n-Read this all the way through before starting\r\n-Take the small box with four holes in it and push the tact switch into it until it's as far in as possible, with the legs poking out of the holes\r\n-Solder two lengths of suitable wire to two of the tact switch legs, long enough to reach your driver board from the planned mounting position. Each tact switch has four legs in two connected pairs; make sure you've soldered to two non-connected legs.\r\n-Take the larger box with a hole that looks like it's designed for 1.75mm filament and thread some filament through it\r\n-Press your small box and tact switch into the larger box, with the tact switch first, so the wires line up with the cut-out in the base of the large box\r\n\r\nNow comes the fun part.\r\n\r\nGet ready to use super glue\r\n-Continue pushing the little box and tact switch home until you feel or hear the switch actuate\r\n-Holding steady, pull out the filament and then re-insert it. Did you feel or hear the tact switch actuate each time? No? Fiddle with it a bit until you've got the positioning right...\r\n\r\nTake your super glue and add a small amount to the gaps between the large and small boxes. Don't overdo it - enough is fine.\r\n-Tact switches really don't like glue, so be careful.\r\n-Keep holding the parts in place until the glue has dried, which is why you should use fast-acting glue\r\n-It's time to recheck that you can feel or hear the switch actuate when you insert or remove the filament from its hole.\r\n\r\nStill no luck? Bad luck - start again.\r\n\r\nYou now need to mount your switch.\r\n-It needs to be placed along the line of your filament before it enters the extruder. After the extruder is absolutely not good, and you also want to avoid adding any unnecessary strain or kinks to the path your filament takes.\r\n\r\nHow you mount the sensor is up to you, as there are many different printers out there, but I can at least make a suggestion:\r\n-Search thingiverse for a filament guide that fits your printer and print it. Mount it just before your extruder\r\n-With your new sensor in hand, you should be able to line it up with your filament path so that you can glue it to the filament guide you printed - the neatest option might be to lop off the end of the guide and replace it with your sensor.\r\n\r\nIt's then a matter of running the wires to the driver board and making the necessary changes to your firmware, so the printer is aware of the sensor. (Google)\r\n\r\nNote:\r\nThe firmware will need to be told whether to act on 'closed' or 'open' circuit. A tact switch is closed when pressed and will be open when there's filament present.\r\n\r\nHurrah! One fewer thing to worry about.\r\n\r\nPS:\r\nYes, this is intended for 1.75mm filament. Don't despair if you're using 3mm filament - just drill out the hole in your favorite 3D package or use a drill to open it up with a bit of luck.