Prusa i3 MK2S filament runout sensor bracket/holder

by Crunch3D Sep 23, 2016
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Thanks! What does your pause script look like?

I use octoprint with it. Sadly i could not get the script to work so this is on pause right now.
I belive there is a bug in the octoprint plugin and i managed to fix it once but i lost the source :-(

Hi, looks nice. But how long does it take to pause the print ? it goes then to the change filament routine ?

I dont know but the time should be plenty as the filament is slowly used. No afaik it does not go to filament change....

Any chance to use this mod without octoprint? Are there any ports on the RAMBO board for this sensor?

AFAIK no you need octoprint for it.

There is a function in Marlin Filament Out Sensor which has to be activated and the right pins defined.
Check the forum http://shop.prusa3d.com/forum/improvements-f14/wire-up-filament-sensor-to-mk2-use-thermister-circ-t2836.html


I made my version and connected to octopi instead. But I know I can make it work with marlin too.

Thank you.

Filament Runout Sensor for Marlin and Octoprint

I just installed this on my Mk2. Running Silver PLA at the moment. I'm getting loads of false positives. The print is pausing every few seconds. The optical detection should be possible unhindered. I removed all obstructions.
Any ideas?

Hi DWeyel,

Well i have the same problem. I'm still searching for the cause and i have some ideas. My sensor is a really crappy one and it only has one correct placement for the filament (when the light goes out) and thats also roughly only as sick as the filament. So it has to be the exact spot. For this reason im in the process of redesigning the holder to get it in the correct position.
However, this could be different with other (more expensive) sensors.

Another problem i came across is that the plugin does have some software issues and a friend of mine did a dirty hack on it. However i lost my pi install and the hack is lost. This is probably not needed any more due to updates i hope but i will definitely work on that till it runs flawless for me. So stay tuned if you want to.
I'm focusing now on the better placement of the filament inside of the holder, but i have very few hours of spare time at hand right now so it will be slowish.....

Have you tested the operation of this design by cutting the filament intentionally, to see how quickly it pauses the print? I'm a bit worried that, due to it's close proximity to the extruder, it won't be able to pause the print quick enough to be able to unload the remaining piece of filament. This is, by far, the best design I've seen yet for a filament sensor on the MK2, I just have that one concern.




I had for now clear filament and could only rudimentary test the sensor, but not if it stopps in time. But i would guess: Yes

Also you can still pull the filament from the hole in the extruder body if you remove the screws from the Idler. This works really well i did this a few times so it will work.

How does this tell you or stop the print? As in does it beep or will it pause the print OR will it stop the print altogether so it is a failed print? Awesome idea though I love it.

Hi audiobull,

You need Octoprint to get it working :-)
The octoprint plugin (software) will tell octoprint to pause the print. Then you can switch filament and resume :-)

Happy printing :-)

NOW the correct STL is uploaded, sorry :-)