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Matthias U
(@matthias-u)
Eminent Member
Filament movement sensor?

Hi,

I'm a bit annoyed about the Prusa's "IR" filament presence sensor. It doesn't detect filament movement and thus stalled prints are not recoverable (the nozzle leaks all over the object and I don't know where it stalled anyway).

Does anybody have plans to replace the thing with a proper mechanical filament movement sensor, like the one for Duet3D (but integrated into the print head assembly, replacing the IR sensor)? I'd tackle this myself, the problem is that I already have too few spare months each week … plus I don't have the 3D design program Prusa built the assembly with – my tool of choice is OpenSCAD.

The Duet3D sensor is here: Duet3D sensor

Posted : 06/01/2020 4:26 pm
manicminergb
(@manicminergb)
Active Member
RE: Filament movement sensor?

ime having probs with filamentium clear tried all i know -same settings on other mats no problem -gonna disable sensor and see what happens mk3s

Posted : 22/01/2020 1:59 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Filament movement sensor?

@rlwhite

Colour shouldn't have any effect on the mk3S filament sensor. (unlike the mk3 original sensor!)
it is probably more a sensor position issue! lots of folk find that fitting one of these, helps

https://www.thingiverse.com/thing:4006603

also, I modified my filament sensors to have LED's
Mk3s mod

mk3S with MMU2S mod

in both instances I have soldered a 5volt LED across the 5volt pin and the output pin on the sensor!
https://www.ebay.co.uk/itm/5-Volt-Red-Green-and-Yellow-LED-5mm-no-resistors-needed-Lot-of-9/123200004146?hash=item1caf4ae032:g:lLwAAOSw3EVbKObV

this lets me see immediately whether the sensor is registering filament presence or not! this simple mod makes filament sensor adjustment, a breeze!  🙂

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 22/01/2020 4:03 pm
Zoltan
(@zoltan)
Member Moderator
RE: Filament movement sensor?

I guess You meant a fillament movement sensor. Its mechanical version you can find below,  next step will be to redesign it by implementing an ir sensor. The light will be interrupted by holes on the bigger wheel and the signal will be processed by arduino nano. Recently you can watch the white dot turning/moving as the fillament moves. When remotly watching with camera you see the fillament movement and react.

https://forum.prusa3d.com/forum/english-forum-awesome-prints-hall-of-fame/fillament-movement-sensor/#post-178220

even an old man can learn new things 🙂
Standard I3 mk3s, MMU2S, Prusa Enclosure, Fusion 360, PrusaSlicer, Windows 10
PRUSA MINI+ Prusalink + Prusa Connect

Posted : 22/01/2020 6:08 pm
Sembazuru
(@sembazuru)
Prominent Member
RE: Filament movement sensor?
Posted by: @joantabb

[...snip...]

in both instances I have soldered a 5volt LED across the 5volt pin and the output pin on the sensor!
https://www.ebay.co.uk/itm/5-Volt-Red-Green-and-Yellow-LED-5mm-no-resistors-needed-Lot-of-9/123200004146?hash=item1caf4ae032:g:lLwAAOSw3EVbKObV

I love those little 5V LEDs. I have some little ones that I got from DigiKey like these T1 LEDs. Their 0.1" pin spacing makes them useful for making an indicator LED on two adjacent pins of an Arduino during development or as a demonstration unit. Just need to be careful to keep normal LEDs from getting mixed into my stock of 5V LEDs.

See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs

Posted : 24/01/2020 5:54 pm
Nikolai
(@nikolai)
Noble Member
RE: Filament movement sensor?

Do they have a current limiter built in?

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 24/01/2020 10:45 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Filament movement sensor?

@nikolai-r

yes! not sure whether it is a dynamic regulator or merely an integrated resistor, but they work well!

 

Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 24/01/2020 11:35 pm
Sembazuru
(@sembazuru)
Prominent Member
RE: Filament movement sensor?
Posted by: @nikolai-r

Do they have a current limiter built in?

Yep. On the ones that I have I can make out a little black speck between the anode leadframe and the bondwire. The little black speck is an integrated current limiting resistor.

See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs

Posted : 25/01/2020 1:21 am
Nikolai
(@nikolai)
Noble Member
RE: Filament movement sensor?

Nice one. Thanks for sharing.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 25/01/2020 1:38 am
waltercrundwell
(@waltercrundwell)
New Member
RE: Filament movement sensor?

@joantabb

Where does this shim actually go? We got our mk3s in September, the autoload worked exactly once and then never worked again. After coaching from Prusa, I needed to take apart my assembly to tighten a wiggly hot end. and suddenly the autoload now works but it seems to stop the filament extruding a couple of layers into the print....which I am assuming its the filament sensor... its been more of a frustration and I would rather just do without... but am willing to try something to get it to work properly, even if we liked how it was working before...lol...I honestly don't have any idea what I did when I reassembled it but I hate tinkering so if I can do without like I have I would rather... The codes in the LCD screen say the filament sensor is off as is the auto load... but clearly that is lying...

Posted : 03/04/2020 7:35 pm
nilok
(@nilok)
Estimable Member
RE: Filament movement sensor?

Try this: https://www.prusaprinters.org/prints/25728-prusa-mk3s-ir-sensor-spacer-set

Is your printer grinding? Bearings squeaking? Motors smoking?
Step 1) Wash your Steel Sheet
Step 2) Return to Step 1

Posted : 03/04/2020 8:02 pm
mpeill
(@mpeill)
Eminent Member
RE: Filament movement sensor?

I have a similar issue with the sensor, not with autoload, but "out of filament" recognition. Out of filament is recognised, but too late and the end of the filament has passed through the toothed gripper wheels. The remaining filament will then not unload, and needs manually removing from the opened idler cover with pliers. This happens every time the filament reel empties part way through a print.

I thought of just making an extension to raise the sensor further up and away from the gripping wheels to give it more time to change state. However, taking the top cover off, I see the filament does not run through the IR sensor, but that the sensor positioned over to one side.

Can anyone explain how the sensing works? I'd then be in a better position to figure out a modification.

Posted : 23/04/2020 2:41 pm
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