No Accelerometer in mk4 but connector present in the mainboard.
 
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No Accelerometer in mk4 but connector present in the mainboard.  

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Goyetus
(@goyetus)
Eminent Member
No Accelerometer in mk4 but connector present in the mainboard.

Mk4 is compatible with Input Shaping as they claim but:

How can you fine-tune your mk4  if  the printer has not any ADXL acelerometer to get the vibration?    Is in the new middle board?  
There must be an acelerometer in the bed,  and another in the x carriage.........

Regards!!!

Ce sujet a été modifié il y a 12 months par Goyetus
Publié : 31/03/2023 1:55 am
OB1
 OB1
(@ob1)
Trusted Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

I've been wondering the same question as well...

Publié : 31/03/2023 2:47 am
Michael
(@michael-2)
Active Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

Input Shaper suppresses these effects by “learning” how the printer moves – this is done by placing an accelerometer in the extruder and interpreting the reported values. The MK4 doesn’t have a built-in accelerometer in the Nextruder, but there’s an accelerometer port on the xBuddy board. We use it to calibrate the Input Shaper and then you can use the pre-calibrated firmware without an accelerometer installed.

Publié : 31/03/2023 5:49 am
Thejiral
(@thejiral)
Noble Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

I am not sure why this crutch solution was chosen instead of measuring vibration directly where they matter, on the extruder? There is already a small PCB on the Nextruder anyway, isn't there? Why not put the accelerometer there?

I'd love to see some indpendent review where they test the original solution as intended by Prusa and then a manual accelerometer calibration with an external accelerometer somehow screwed to the nextruder. Maybe the differences in achievable quality are not significant, maybe they are. Probably also depends on the larger setup so it should be tested with the printers just on some shacky LACK and on a proper shelf/table on top of a concrete slab. 

Mk3s MMU2s, Voron 0.1, Voron 2.4

Publié : 31/03/2023 9:21 am
Zbigniew Trzepizur
(@zbigniew-trzepizur)
Trusted Member
RE:

 

Posted by: @thejiral

I am not sure why this crutch solution was chosen instead of measuring vibration directly where they matter, on the extruder? There is already a small PCB on the Nextruder anyway, isn't there? Why not put the accelerometer there?

I'd love to see some indpendent review where they test the original solution as intended by Prusa and then a manual accelerometer calibration with an external accelerometer somehow screwed to the nextruder. Maybe the differences in achievable quality are not significant, maybe they are. Probably also depends on the larger setup so it should be tested with the printers just on some shacky LACK and on a proper shelf/table on top of a concrete slab. 

I think you got that wrong. They don't mean they take measurements at the xBuddy board. It most likely means they are using this port during the development process for connecting an extruder-mounted accelerometer to characterize the system and create relevant software models. It just means they don't ship the actual sensor with each and every printer. With all the printers leaving the factory being identical (for all intents and purposes) that seems to make sense unless you start modding yours. My question would be: what do you do when you modify your printer enough to invalidate the original profile. Are you on your own or is there a procedure to mount an actual accelerometer on your modified extruder and re-calibrate it via some firmware feature.

Publié : 31/03/2023 10:00 am
Goyetus
(@goyetus)
Eminent Member
Topic starter answered:
RE: No Accelerometer in mk4 but connector present in the mainboard.

Im really lost.  Its a total mess.  

The printer will not have the same vibration in a "lack table"  or in a granite with foam !     The ressonance  is not the same,  the vibration is not the same.

If it´s "harcoded" ,  and cant be "finetuned"  at home,   it is stupid  (I think).   

I use ADXL with Klipper in my Bear ,   and the results are different. 

Publié : 31/03/2023 10:25 am
Razor a aimé
Thejiral
(@thejiral)
Noble Member
RE:

Ok, that would clarify a bit but it would still make it a crutch solution. There is a reason after all why usually an accelerometer is used on the extruder on the specific printer at the specific print location and environment, when doing the input shaper calibration for that specific printer. The reason is that all those specific factors can have a large influence on resonance frequencies and that does not only affect modded printers, but all printers as the setup and physical properties of tables etc differes for each printer (and again if you move a printer to a new location). 

One can try to do a one fits it all calibration at factory but it will be inferior to properly individually calibrated input shaper. 

We are totally speculating here but if Prusa does not at least offer the option for relatively easy proper end user calibration with accelerometer (as available add on or at least with the interface to plug in some common accelerator probes), including an easy to use firmware implementation of that proper calibration, this would be really disappointing. 

Ce message a été modifié il y a 12 months par Thejiral

Mk3s MMU2s, Voron 0.1, Voron 2.4

Publié : 31/03/2023 10:52 am
Man Of Kent et Zakoplex ont aimé
Thejiral
(@thejiral)
Noble Member
RE:

 

Posted by: @goyetus

Im really lost.  Its a total mess.  

The printer will not have the same vibration in a "lack table"  or in a granite with foam !     The ressonance  is not the same,  the vibration is not the same.

If it´s "harcoded" ,  and cant be "finetuned"  at home,   it is stupid  (I think).   

I use ADXL with Klipper in my Bear ,   and the results are different. 

Indeed. But leaving out the accelerometer when the addition is actually faciliated somehow makes even less sense. Those components are small, lightweight and don't cost much. I am a bit lost here too. 

I do have input shaper on my Voron 0.1, calibrated with an ADXL. The difference in print quality with input shaper is like day and night. I also think to see a slight degradation in results after having not recalibrated for quite a while, even though slight details have changed. 

Like I said, this would necessitate a thorough review in different resonance setups (LACK, concrete slab, concrete slab on solid table etc) to see how much of a difference it does make in practice. 

Ce message a été modifié il y a 12 months par Thejiral

Mk3s MMU2s, Voron 0.1, Voron 2.4

Publié : 31/03/2023 10:56 am
Razor a aimé
Artur5
(@artur5)
Reputable Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

You're totally right guys. Pre-calibrated input shaper on factory is worthless. Even more so for kit printers, because the way one user may tighten the screws or fit the parts together will be slightly different from the way another user will do it. Every printer unit requires custom calibration, because every little thing changes the resonances ( enclosure or not, additional feet for better dampening, spool holder set-up..). Even humidity and temperature play a role, albeit small.

Publié : 31/03/2023 11:21 am
Man Of Kent et Razor ont aimé
stevQ
(@stevq)
Trusted Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

I think the main problem might be: Measuring vibration values on the extruder only covers the X and Z axis in a bedslinger. You would need a second sensor on the bed itself for the Y axis measurement.
Still hope they can clarify, how we cancalibrate on our own (e.g. when chaning the extruder / hacking it). A cable with a sensor to first put on the extruder and in a second step on the printbed could work for example.

But knowing that this could be possible (from SW side also) just makes me hesitant to buy into the MK4.

Publié : 31/03/2023 1:04 pm
Thejiral, Zakoplex et Razor ont aimé
Razor
(@razor)
Estimable Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

You all are playing where the puck is, not where it will be. This is obviously a MK4S feature. 😉

Seriously though, I agree 100% with all of you. Adding the required sensors is a fraction of a fraction of the BOM. Different tables mounts, wear, parts, even different assemblers at Prusa will all influence each machine differently. Yes it's a small difference, but we're talking small variances in the first place. Why not get it perfect on each machine as conditions/component wear occurs?

Mini+MK3S+XL 5 Tool

Publié : 31/03/2023 2:47 pm
Goyetus
(@goyetus)
Eminent Member
Topic starter answered:
RE: No Accelerometer in mk4 but connector present in the mainboard.

+1

Publié : 31/03/2023 3:30 pm
Goyetus
(@goyetus)
Eminent Member
Topic starter answered:
RE:

They have to clarify this situation.   
 The info given in the "live event"  is not enough.   

We need to know:
- Prusa Understands  that  the vibration in their labs  is not the vibration  in a lack table  or in a granite+foam base? 
- Can we purchase an acelerometer?
- Can the Firmware  Fine-tune the printer in X and Y  with the acelerometer?

Please,  any admin/dev  could anser this ?

Ce message a été modifié il y a 12 months 2 fois par Goyetus
Publié : 31/03/2023 4:08 pm
Man Of Kent a aimé
D0MINGU35
(@d0mingu35)
New Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

And you are talking about the MK4. But if you upgrade MK3S to MK3.5 you will have "input shaping" and find different frame, different extruder, different Zrods , the bed don't mount in the same way, and possibly a lot of modifications made by the user itself since this is a open source platform....

I can't get how this will work in every printer....

Publié : 31/03/2023 4:16 pm
Walter Witt
(@walter-witt)
Eminent Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

Here's another thing worth mentioning. As you print, the mass of the print bed increases as the print gets bigger. Won't this also effect the Y axis Vibration?

 

All I can say is, they better have an accelerometer accessory for sale soon.

Publié : 31/03/2023 4:18 pm
Zakoplex et Razor ont aimé
Goyetus
(@goyetus)
Eminent Member
Topic starter answered:
RE: No Accelerometer in mk4 but connector present in the mainboard.

Thanks @L&OR  ,you are right!  

I asked prusa directly in twitter.  

Please,  FEEL free to give lot of LOVE  and  add more questions about this......

It´s awfull  and disrespectful  if they think the community is not worried about this.

https://twitter.com/goyetus/status/1641836451846291462

Publié : 31/03/2023 4:21 pm
Goyetus
(@goyetus)
Eminent Member
Topic starter answered:
RE: No Accelerometer in mk4 but connector present in the mainboard.
Posted by: @d0mingu35

And you are talking about the MK4. But if you upgrade MK3S to MK3.5 you will have "input shaping" and find different frame, different extruder, different Zrods , the bed don't mount in the same way, and possibly a lot of modifications made by the user itself since this is a open source platform....

I can't get how this will work in every printer....

I have an answer,  but you are not going to like it.
You can measure "vibration"  the same way  Marlin 2.1  does.    With a Test print  and a caliper.   Mike from Teaching Tech has a good video about this. 
BUT this is not the way to go. 

Publié : 31/03/2023 4:23 pm
jseyfert3
(@jseyfert3)
Reputable Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

Here's another thing worth mentioning. As you print, the mass of the print bed increases as the print gets bigger. Won't this also effect the Y axis Vibration?

Yes, but the mass addition over the course of the print is already known.

Publié : 31/03/2023 4:53 pm
Zbigniew Trzepizur
(@zbigniew-trzepizur)
Trusted Member
RE: No Accelerometer in mk4 but connector present in the mainboard.

 

Posted by: @goyetus

It´s awfull  and disrespectful  if they think the community is not worried about this.

Awful and disrespectful? Dude, take a walk, look at some trees, breathe deeply for a while and calm the fudge down 😀 

Publié : 31/03/2023 5:51 pm
Fnord Prefect et MikeH ont aimé
Goyetus
(@goyetus)
Eminent Member
Topic starter answered:
RE:

You are right.  Too many emotions in the air 🙂  ,  and lot of question without answer 😛  
Hope prusa can clarify the situation. 

Im being dramatic about:  "The community is using ADXL , klipper,  etc  long ago ,    it´s not "clear"  to say   "all is configured in our labs,  dont worry".    Yes,  WE worry,  couse we know how this things work......

 

Posted by: @zbigniew-trzepizur

 

Posted by: @goyetus

It´s awfull  and disrespectful  if they think the community is not worried about this.

Awful and disrespectful? Dude, take a walk, look at some trees, breathe deeply for a while and calm the fudge down 😀 

 

Ce message a été modifié il y a 12 months par Goyetus
Publié : 31/03/2023 6:57 pm
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