Filament runout sensor

Just wondering if you can list some info on filament runout sensor details that will be in 4.1 release so we can prepare for it.

The basic function of these is a switch that is either normally open or normally closed that will change state when the error occurs.

If that is so, can you tell us what GPIO pin you will use, and any other relevant info . That way we can get it all wired up in advance if we want. (and also help you test it in beta versions)


I have the required material, but I have not yet decided of the technical details. And frankly, after the release of version 4, I will take some rest and fix bugs before developing something new.


Like i’ve said elsewhere, no rush!
You deserve a holiday. Sorry I can’t afford more on my patreon donation!

What about using the left over Z-Endstop hardware that is no longer needed if you are using the BL-Touch? Most of the wiring is already there, it would be a simple matter of extending some wiring, and re-locating the switch.

However, for those who are not using a BL-Touch mod this could pose a problem.

Not a viable solution. As you said, some people do not have a bltouch. There is enough free pins on the EXT connector. But I have not yet decided which one I will use.

I just installed 4.0.3 and it’s working great! Thanks @andrivet!! m also very excited about the prospect of a runout sensor in 4.1. I’ve considered attaching one to my OctoPrint server but it seems so much more elegant to have it as a part of the printer. @andrivet let us know if you need testers

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I just picked up an i3+ and flashed your firmware. It is working great but I was looking at using the free pin 23 from the z axis as [wikkedstorm] mentioned and was searching for any known issues. I can see why you can’t brew it in since not everyone is going to have bltouch or want to add the sensor. Do you see any problems with me enabling the FILAMENT_RUNOUT_SENSOR with FIL_RUNOUT_PIN 23 for a custom build? I was just going to try it but I thought I would ask first.

No idea sorry. I plan to look at this in the future, but did not for the moment.

And when I will implement filament runout sensor, I will not use pin #23 for sure. I wanted something that will work for everyone.

Just to add my 2 cents worth @johnboiles, getting a BL-touch is the best thing I ever did. It makes a huge difference to the quality of the prints. It is well worth the investment. I wouldn’t use a printer or cnc milling machine without some sort of digital height probe. No matter how well you think you’ve levelled it by hand, a probe will always do a better job. (and who wants to level the bed by hand every print. ughhhh!)

With the release of v5 was the filament runout feature included?

This is planned for version 5.1. You can find more information here: Version 5.1 and results of votes