Filament sensors

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1

I have a prusa mini and lots of end of roll filament.
I’m looking into a filament runout sensor that will pause the printer so I can load new.

Prusa has one for the mini, but the cheapest shipping is nearly the same cost as the sensor.

I’m assuming there are other brands that will work with the pursa mini?
any recommendations? preferably something that can be ordered from Amazon.

Thanks

2

Mine is a microswitch, same kind you’d use as an end stop, in a printed enclosure. Filament holds the button on the switch down. When the filament runs out, the switch opens. I’ve also seen some based on optical sensors, like the ones built into the Prusa R4 (I believe) extruder bodies.

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3

The MMU3 uses an optical sensor, the MK4 works with magnets.

4

The R4 extruders use an optical sensor and printed flag, and the flag uses opposing magnets rather than a spring.

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5

I take it the MMU3 and R4 are both Prusa brands - at least the quick web search makes it look like that.
if that is the case, those would have the same issue as purchasing the sensor for the mini which shipping cost is rediculous.

should something like this work?
https://www.amazon.com/BIGTREETECH-Filament-Runout-Detector-Octopus/dp/B0C7PZDBNC/ref=asc_df_B0C7PZDBNC/?tag=hyprod-20&linkCode=df0&hvadid=693071814430&hvpos=&hvnetw=g&hvrand=13617319878097839207&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9017486&hvtargid=pla-2203722552149&mcid=3cc541b488c13f059c656e361981698e&gad_source=1&th=1

or this one
https://www.amazon.com/Creativity-Printer-Filament-Detection-Detecting/dp/B087325BPG/ref=asc_df_B087325BPG/?tag=hyprod-20&linkCode=df0&hvadid=693071814430&hvpos=&hvnetw=g&hvrand=13617319878097839207&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9017486&hvtargid=pla-1191340719837&mcid=35a185be1aba3d19a7523f2c325fb158&gad_source=1&th=1

Or would any of the filament sensors on thingyverse be just as good? Looks like there a numerous microswithc types.

6

I printed the one I use off of Thingiverse. It was long enough ago that I don’t know that I could find it again…

Its like this one Microswitch filament runout sensor by eussrh - Thingiverse
or this one Filament runout sensor by Hikage - Thingiverse. I have a direct-drive extruder so don’t need the bowden tube connections.

7

The one on my FLSUN SR is just a microswitch in a housing. The runout implementation is fantastic. It stops. Backs the filament out and waits till I change it.

8

Thanks guys, I’ll check those out for now and see how it works

9

OK, I know its been a while, but I’m finally getting to setting up a filament sensor.
I have the two wire microswitch style but when I plug it in the sensor port on the prusa mini board it tells me it is not connected.

here is where I am plugging it in.

image
image1480×1184 109 KB

the prusa instructions are not clear and are intended for the runout sensor that prusa sells, that use a 3 wire connections.

Hoping someone can help.

thank you

10

I don’t have that board, so can’t tell which pins are which, but you want the switch to connect the Signal and Ground pins at the board. The 5 volt positive connection is used to run the circuitry for the optical sensor and LED, which you don’t have when using a simple switch.

11

Thanks @ttraband . I’ll dive into it a bit more.
Feedback on the prusa forums indicate it won’t work and I have yet to find an example of using this kind of switch on a prusa mini.

12

That’s the right place for detailed support of a Prusa product.
If the Prusa design expects a smart filament sensor (e.g. it either has an encoder to count motion steps, or has a microcontroller to report detailed telemetry) then it won’t work without making a firmware modification.

A good reason to buy the Prusa switch.

13

yeah, that’s where I’m heading. Just sucks that shipping is slightly less than the part itself.

14

Hah, finally an advantage of living in Europe!! Now you know how it feels to order from Ryan. :stuck_out_tongue:

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