Author Topic: Best filament motion sensor? Design or buy?  (Read 4688 times)

0 Members and 1 Guest are viewing this topic.

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Best filament motion sensor? Design or buy?
« on: January 14, 2022, 03:22:50 am »
This is why:



sooo... I got the BTT smart filament sensor but I did not like the design and returned it.

Then I started an investigation what is available that passed my quality standards, and here that I found.

1)  Pandapi3d.com Laser Filament Motion Sensor

https://github.com/markniu/Laser-Filament-Motion-Sensor

Over complicated but definitely clever design.
I do not think it will work reliably with every printer out there, too many variables in play.

Very clever design anyway, he deserve an applause...  :clap:

2) Duet3D Filament Monitor: Laser Version

https://duet3d.dozuki.com/Wiki/Duet3dFilamentMonitor_LaserVersion

Out of stock, there are some clones on ebay and somewhere else.

Again nice design...

3) Duet3D Filament Monitor: Rotating Magnet Version

https://duet3d.dozuki.com/Wiki/Duet3dFilamentMonitor_RotatingMagnetVersion
Out of stocks.

Here my thoughts:

The optical tracking sensors do not convince me fully, from the Duet laser sensor:

Quote
Different filament materials and colours are detected with varying degrees of accuracy by the laser sensor. For most filament types this can be handled through setting an appropriate trigger value for the sensor. The sensor is accurate enough in most tested filaments to allow the print to be paused for filament run-out, jam or tangle, those filament types the sensor is less sensitive to may have 1-2mm of error in movement detection. Depending on where in the print the extruder jam or filament strip occurs will determine how much of an impact 1-2mm of unfed filament will have on the print. The sensor is proving to be inaccurate with certain PETG filament, especially from ESUN (Black tested so far) and is not recommended for this.

BTW I could not find any optical tracking sensors on the market to play with, everything out of stocks. Avago or Pixart... and I did not want to buy used mouses to tear down....

The magnetic ones is cool, but we can do better in the mechanical part, and also I do not know robust it is to high current PWM noises like the one in 3D printers.. it should be no problem thow.

I am now designing my own, based on the CTS 292 optical encoder sensor.
I want to keep it simple and send the pulses to the main Marlin µC which is the master.

I do not like to have a "too clever" µC in the sensor, since the config/adjustment could be a pain. I still prefer to have all my settings in Marlin conf file.
I still plan to throw a 8bit 8 pin PIC on mine, but just for very stupid stuff. The hard work should be done in Marlin.

What do you think?

I would like to know the opinion of other EE.

Thanks in advance!






« Last Edit: January 14, 2022, 03:28:50 am by Zucca »
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline mazurov

  • Frequent Contributor
  • **
  • Posts: 523
  • Country: us
Re: Best filament motion sensor? Design or buy?
« Reply #1 on: January 14, 2022, 09:21:25 pm »
This is why:

What is the problem you're trying to solve? If you want to stop the printer before the filament start stretching motion sensor won't help you. If you want to stop after simply monitor the stepper current - when the filament is stripped in the extruder the change in current is quite noticeable.

If you want filament motion sensor take a look at Infidel and use raw (non-averaged) signal to detect motion.  You may need to add a signal conditioning circuit to it to better see small changes.
With sufficient thrust, pigs fly just fine - RFC1925
 

Offline thm_w

  • Super Contributor
  • ***
  • Posts: 4431
  • Country: ca
  • Non-expert
Re: Best filament motion sensor? Design or buy?
« Reply #2 on: January 14, 2022, 10:06:13 pm »
Can Marlin measure the current from TMC2208/9 and report back? Otherwise you are building a current measurement system which seems just as complicated.
Although it may have other benefits.

If you want filament motion sensor take a look at Infidel and use raw (non-averaged) signal to detect motion.  You may need to add a signal conditioning circuit to it to better see small changes.

https://github.com/drspangle/infidel-sensor

Interesting idea
Profile -> Modify profile -> Look and Layout ->  Don't show users' signatures
 

Offline EverydayMuffin

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ie
Re: Best filament motion sensor? Design or buy?
« Reply #3 on: January 14, 2022, 11:10:58 pm »

BTW I could not find any optical tracking sensors on the market to play with, everything out of stocks. Avago or Pixart... and I did not want to buy used mouses to tear down....


Pixart have a sensor for this application, the PAT9125.

https://www.epsglobal.com/products/semiconductors/sensing-and-haptics/optical-tracking/low-power-optical-tracking-miniature-chi

Used here: https://help.prusa3d.com/en/article/filament-sensor-mk3-non-s_2125/

 

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #4 on: January 15, 2022, 02:05:22 am »
What is the problem you're trying to solve?

see picture Tangled spool, I want to stop/pause the printer when the spool is tangled.
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #5 on: January 15, 2022, 02:08:59 am »
Can Marlin measure the current from TMC2208/9 and report back?

I think yes in diag mode. BTW the home stops could work with current detection AFAIK.
But I do not need that.
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #6 on: January 15, 2022, 02:10:01 am »
If you want filament motion sensor take a look at Infidel and use raw (non-averaged) signal to detect motion.  You may need to add a signal conditioning circuit to it to better see small changes.


Don't like the idea to use a diameter sensor to sense motion. Better design something for motion movement in first place.
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #7 on: January 15, 2022, 02:11:13 am »
Pixart have a sensor for this application, the PAT9125.

https://www.epsglobal.com/products/semiconductors/sensing-and-haptics/optical-tracking/low-power-optical-tracking-miniature-chi

Used here: https://help.prusa3d.com/en/article/filament-sensor-mk3-non-s_2125/

Eh I know, do you think it is reliable will ALL filaments?
BTW I can't find it in stock anywhere. I sent an email and see.
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #8 on: January 15, 2022, 02:12:53 am »
BTW I think the magnetic encoder is convincing me.

PLAN A: a magnetic encoder
PLAN B: optical encoder

Thanks for all the comments BTW!
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 
The following users thanked this post: Old Printer

Offline EverydayMuffin

  • Regular Contributor
  • *
  • Posts: 64
  • Country: ie
Re: Best filament motion sensor? Design or buy?
« Reply #9 on: January 15, 2022, 09:20:18 am »
Eh I know, do you think it is reliable will ALL filaments?
BTW I can't find it in stock anywhere. I sent an email and see.

You said earlier that you didn't want to take apart a mouse to get a sensor. The PAT9125 is NOT a mouse sensor.

Mouse sensors are optimised for tracking surfaces which are exactly 2.4mm away from the sensor. The PAT9125 will offer better performance than a mouse sensor. There are boards available here:

https://www.codico.com/en/pak9125ls-tkit
« Last Edit: January 15, 2022, 09:26:22 am by EverydayMuffin »
 

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #10 on: January 16, 2022, 03:57:34 am »
You said earlier that you didn't want to take apart a mouse to get a sensor. The PAT9125 is NOT a mouse sensor.

Ciao EMuffin,
Yeah I said that because since I could not find any PAT9125 in stock anywhere, to me it was making no sense to tear apart a mouse to have something to play with.
I mean I could had a optical tracking sensor for free in one old mouse, but it makes no sense.

The PAT9125 will offer better performance than a mouse sensor.

Yes it looks like you are right, but I am missing the details....
I mean this looks promising...



but I do not care about rotation... I want precision in how much the shaft/filament moved.

Since it is used by pandapi and prusa, it is surely a good sign.
How can we know for sure the PAT9125 can work reliably with a 3D printer filament regardless the color and the material?

Duet uses PAT9130, with has better resolution but not ideal DOF, in my eyes.

I can also see the PAT9125  I2C registers



but it does not give me all the details I need... for example why two sleep configuration and who to deal with them?


I have also to admit I do not have to much knowledge on optical tracking sensors, can you what I have to do to learn the nuts and bolts of those sensors?

Many many thanks for the link, I wait until Tuesday an answer from epsglobal if not I pull the trigger with codico.

Grazie!
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #11 on: January 16, 2022, 04:43:45 am »
Interesting

Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline Monkeh

  • Super Contributor
  • ***
  • Posts: 7684
  • Country: gb
Re: Best filament motion sensor? Design or buy?
« Reply #12 on: January 16, 2022, 04:47:02 am »
Since it is used by pandapi and prusa, it is surely a good sign.

Prusa abandoned them for being unreliable.
 
The following users thanked this post: Zucca

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #13 on: January 16, 2022, 04:57:27 am »


Ah ah....

That's why I ask so many questions.... optical tracking sensors did not convinced me 100%!!!!!
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline natman69

  • Regular Contributor
  • *
  • Posts: 54
  • Country: it
 

Offline dl6lr

  • Frequent Contributor
  • **
  • Posts: 440
  • Country: de
Re: Best filament motion sensor? Design or buy?
« Reply #15 on: January 19, 2022, 04:10:54 pm »
Maybe these two projects can inspire you:

https://hackaday.io/project/18804-coversion-of-ps2-mouse-to-filament-counter

https://www.toybuilderlabs.com/products/tunell-3d-printer-filament-monitor

I would upvote the usage of a friction driven wheel with an optical encoder. If upcycling an old mouse, you could additionally use a tactile switch on the wheel for the runout detection, so you can distinguish filament runout from clogging.
 

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #16 on: January 21, 2022, 01:02:46 am »
https://www.toybuilderlabs.com/products/tunell-3d-printer-filament-monitor

Thanks this one is promising! well done design!
That said, I want to try a magnetic encoder, I think is has less friction.
« Last Edit: January 21, 2022, 03:34:36 am by Zucca »
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #17 on: January 21, 2022, 01:03:41 am »
I would upvote the usage of a friction driven wheel with an optical encoder. If upcycling an old mouse, you could additionally use a tactile switch on the wheel for the runout detection, so you can distinguish filament runout from clogging.

In both cases I need the printer to pause, I do not see personally the point to make a difference between the two.
BTW the AS5601 can detect a push button event too, and it is magnetic.
« Last Edit: January 21, 2022, 04:52:18 am by Zucca »
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline dl6lr

  • Frequent Contributor
  • **
  • Posts: 440
  • Country: de
Re: Best filament motion sensor? Design or buy?
« Reply #18 on: January 21, 2022, 09:25:46 am »
I would upvote the usage of a friction driven wheel with an optical encoder. If upcycling an old mouse, you could additionally use a tactile switch on the wheel for the runout detection, so you can distinguish filament runout from clogging.

In both cases I need the printer to pause, I do not see personally the point to make a difference between the two.

If you just have a runout, the print is paused (you could start filament change) but the print is without error up to the end of filament.
If you have a knot and the filament strips, the non-existent movement is detected later (after timeout), as you will have at least some delay until the filament not moving is detected. I would expect the print to be damaged already.
The best movement detection would be to couple the filament sensor directly to the extruder (without any slack) and correlate the sensor signal with the extruder movement. This is the case with Prusa, where the motor stall can be monitored with the Trinamic drivers and the runout is detected with an optical switch at the extruder lever.
 
The following users thanked this post: Ian.M

Offline Zucca

  • Supporter
  • ****
  • Posts: 4068
  • Country: it
  • EE meid in Itali
Re: Best filament motion sensor? Design or buy?
« Reply #19 on: January 21, 2022, 01:41:40 pm »
It depends.

My goal is to trigger the filament problem with 1mm sensitivity. 3mm it would be still acceptable IMHO.
That said if the filament tangled in an infill area I would not consider automatically the print wasted.

Printer paused, user comes and assess the situation. From a paused state you can always abort.
Can't know what you don't love. St. Augustine
Can't love what you don't know. Zucca
 

Offline mushroom

  • Regular Contributor
  • *
  • Posts: 117
  • Country: fr
Re: Best filament motion sensor? Design or buy?
« Reply #20 on: July 05, 2022, 01:45:56 am »
I know, 6 months...

The answer :



https://github.com/yet-another-average-joe/The_Smart_Spool_Holder

Designed this a few years ago, still using it. Saved a print yesterday.
Not for all machines, but easy to redesign if needed.
Will not detect a clogged hotend, but will never fail in other situations (it just can't) : tangles, end of spool, broken filament.
Costs nearly nothing. No sensors that never work. Mechanical problem solved with a mechanical answer = simple design (didn't find how to make this work with one switch only, keeping the design simple).
If Marlin is properly configured, the print cannot fail : M600 -> replace filament and resume.
 
The following users thanked this post: thm_w, JohnG

Offline Mechatrommer

  • Super Contributor
  • ***
  • Posts: 10839
  • Country: my
  • reassessing directives...
Re: Best filament motion sensor? Design or buy?
« Reply #21 on: July 05, 2022, 04:38:07 am »
Can Marlin measure the current from TMC2208/9 and report back? Otherwise you are building a current measurement system which seems just as complicated.
Although it may have other benefits.

If you want filament motion sensor take a look at Infidel and use raw (non-averaged) signal to detect motion.  You may need to add a signal conditioning circuit to it to better see small changes.
https://github.com/drspangle/infidel-sensor
Interesting idea
i think its to read filament diameter, maybe good to detect if filament exhausted, not to detect stucked filament.

What is the problem you're trying to solve?
see picture Tangled spool, I want to stop/pause the printer when the spool is tangled.
thats the result of unspooling and then respooling incorrectly.

..i'm thinking of similar construction like the infidel sensor "clip" mechanism but using optical encoder (instead of magnet and hall) to detect whether filament is moving or not. and then modify marlin's code for extruder stepper motor movement based on filament movement (encoder)... its like closed loop motor. but it will take some courage to built the sensor and recode the marlin. ymmv.
Nature: Evolution and the Illusion of Randomness (Stephen L. Talbott): Its now indisputable that... organisms “expertise” contextualizes its genome, and its nonsense to say that these powers are under the control of the genome being contextualized - Barbara McClintock
 

Online Ian.M

  • Super Contributor
  • ***
  • Posts: 11612
Re: Best filament motion sensor? Design or buy?
« Reply #22 on: July 05, 2022, 05:16:34 am »
The problem is: when the filament has stopped moving because of a jam, the print is already compromised.  Also unless you have a Bowden feed setup, or mount the filament sensor on your direct drive printhead (undesirable because of added weight, obstruction to access for filament loading, and the extra wires needed to the printhead), the filament motion is not well correlated with extruder stepper movement, due to the printhead motion pulling on the filament above it. 

Furthermore, in non-Bowden setups, a filament jam is likely to pull hard enough on the gantry as the head carriage moves to cause the X stepper to loose steps (or Y as well in a CoreXY machine), and before extrusion fails completely, compromise the layer height by deflecting the gantry and head carriage, either or both resulting in a failed print before the lack of extrusion fails it.

To avoid this and pause the print before it fails, you need to detect the jam as it starts to occur.  It would be worth investigating a filament tension sensor, consisting of three V grooved ball bearings in the same plane with the filament running over them, two fixed on one side of the filament and one on the other side, between the first two, on a sprung lever arm that operates a microswitch.  If the filament tension becomes excessive it will attempt to straighten the filament path through the bearings, deflecting the lever against the (adjustable) spring tension, and operating the microswitch.   

You'd probably also want a filament runout sensor to detect filament breaks.
« Last Edit: July 05, 2022, 05:19:20 am by Ian.M »
 

Offline mushroom

  • Regular Contributor
  • *
  • Posts: 117
  • Country: fr
Re: Best filament motion sensor? Design or buy?
« Reply #23 on: July 05, 2022, 10:11:43 am »
...It would be worth investigating a filament tension sensor...

This is exactly what my design does. And it 100% works.
But it's not complicated/expensive enough.

If the filament tension becomes excessive it will attempt to straighten the filament path through the bearings, deflecting the lever against the (adjustable) spring tension, and operating the microswitch.

This cannot work because the filament is not sstraight ; it has a curvature, and this curvature is not the same from the beginning to the end. And what about PETG vs TPU ?
« Last Edit: July 05, 2022, 10:32:03 am by mushroom »
 

Online Ian.M

  • Super Contributor
  • ***
  • Posts: 11612
Re: Best filament motion sensor? Design or buy?
« Reply #24 on: July 05, 2022, 11:12:45 am »
Certainly the filament isn't straight, as can be clearly seen if you lay an offcut on a flat surface, and if you wanted to *MEASURE* small tensions accurately, this would be a problem.  However you only need to detect over-tension before it jams completely, so as long as the distance between the V groove bearings is sufficiently large compared to the filament diameter, so that the force due to the stiffness of the filament is small compared to the force due to tension at the over-tension threshold, and the filament is deflected through a sufficient angle by the middle roller so that it remains in contact in spite of its curvature, when not under tension, the usual three roller method of running tension measurement is very likely to be practicable.
« Last Edit: July 05, 2022, 11:16:48 am by Ian.M »
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf