Custom MCU-module for UP! Mini...

Post improvements made for UP, and share ideas.
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Michael_K
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Custom MCU-module for UP! Mini...

Post by Michael_K » Thu Aug 29, 2013 10:10 am

Well, I'm about to make one.
I plan to use LPC1758 and slightly modified r2c2 firmware...

Anybody interested?
Any comments?
What about needed features?

marto
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Re: Custom MCU-module for UP! Mini...

Post by marto » Mon Sep 16, 2013 12:34 pm

Interested. Let me know what you figure out.

Steve

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Michael_K
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Re: Custom MCU-module for UP! Mini...

Post by Michael_K » Mon Sep 16, 2013 3:11 pm

Well.
In fact I had no much time for that recently.

For now I have assembled my module and all the printer hardware looks working fine in basic tests.
(USB, SD-card, steppers, heaters, limits etc.)
SAM_6214.JPG
SAM_6214.JPG (179.34 KiB) Viewed 29089 times
The main thing I've figured out that it was not so clever idea - to choose the r2c2 hardware and firmware as a reference :D
In fact It's not a real problem - just a sort of inconvenience.

Anyway, the deeper I dug r2c2 firmware, the stronger I wanted to rewrite it from the scratch... So, finally, I started do that.
I think it will take couple of weeks as I'm really busy for now.

(I know my english is not perfect, sorry).

marto
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Re: Custom MCU-module for UP! Mini...

Post by marto » Mon Sep 16, 2013 10:45 pm

Lol well you obviously have more time than me. Thats pretty cool I really don't know if there is much point in using other firmware on the printer, I was more interested in convincing my up mini to accept the UP firmware so that it could print at 0.15 and also so I could manipulate the temperature.

I am still interested to see what the results are like though. An alternative firmware would be a great options for those looking for more customisation.

Steve

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Michael_K
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Re: Custom MCU-module for UP! Mini...

Post by Michael_K » Tue Sep 17, 2013 12:49 am

Well. The counterquestion is what features of UP software seem so attractive to you?
For me almost the only good thing (but it's really good) is easy-removable support. What's else?

We can not print lithophane or one-perimeter vase, we can not choose support-free mode or wavy infill to prevent bending, we can not even use PLA normally (although printing PLA on any other 3D-printer is muuuch easier than ABS).
OK. may be some features are not really useful, but...

...every homemade printer can do it, but not mine!... Well... I feel myself cheated... kind of... 8-)

Finally It's just an interesting hobby project :)

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JuliaDee
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Re: Custom MCU-module for UP! Mini...

Post by JuliaDee » Tue Sep 17, 2013 3:22 am

Michael_K wrote:We can not print lithophane or one-perimeter vase
Really? The "Surface" option doesn't give one-perimeter printing? I thought that's what it was for.

Up software now has a no-support option - just select "Base Only" from the minimum area drop-down. I've never really had a burning desire for wavy infill. Shell Mode is pretty brilliant, I don't know if that's common in the open source world or not.

I've seen some nice lithophanes done on Ups. In fact, the first FDM lithophanes I ever saw were done on Ups.

The easily-removable support is not to be underestimated as a compelling advantage to Up firmware/software, although you are certainly right about limited control over speed, retraction, and temperature being drawbacks for advanced users.

I personally find the Up's compromise between ease of use and configurability to be pretty darned good. Its support generation algorithm does just about everything I've ever needed. A support preview (which many have asked for) would be a really useful feature for visualizing the results of the selected options prior to printing.

julia

roller
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Re: Custom MCU-module for UP! Mini...

Post by roller » Tue Sep 17, 2013 4:14 am

"Base Only" still produces support for the first 8mm (approx) - really annoying with Surface as the support is way stronger than the print.

Surface is flawed compared to open source implementations. Single wall prints which work fine on a reprap with a similar nozzle size and layer height do not print well on the Up using the surface option. There are horizontal gaps left in the print and it seems to be an issue with the algorithm and the estimated width of layed filament.

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Michael_K
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Re: Custom MCU-module for UP! Mini...

Post by Michael_K » Tue Sep 17, 2013 4:58 am

JuliaDee wrote:The "Surface" option doesn't give one-perimeter printing? I thought that's what it was for.
Yes it does. But who need bottomless vase?
JuliaDee wrote:Up software now has a no-support option - just select "Base Only" from the minimum area drop-down.
Hmm... I didn't notice that. Thanks. (They should update manual long-long time ago...)
JuliaDee wrote:I've seen some nice lithophanes done on Ups. In fact, the first FDM lithophanes I ever saw were done on Ups.
It's interesting. What about infill structure? Were they solid inside?

Julia, I agree with you about support generation algorithm.

But I saw also much better top-bottom surface quality on other printers (as they can fine-tune the extrusion flow amount), as well I saw the gap between perimeter and top surface on UP on some models (even with original plastic), hollow thin walls etc.
All those small issues push me to make my own controller.

On other printers I can AT LEAST TRY to improve the quality of every certain model. (while In most cases the quality of UP is more than needed, I agree!). With UP I have no chance.

I can guess that UP developers found some compromise. But sometimes user may want different preferences or priorities, he needs "another compromise".

Give me those rakes back, I want to step! :)

roller
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Re: Custom MCU-module for UP! Mini...

Post by roller » Tue Sep 17, 2013 6:49 am

top surface on UP on some models (even with original plastic), hollow thin walls etc.
No infill on thin walls is a result of the slicing algorithm and will happen in every slicer at a certain wall thickness. You need to jiggle wall thicknesses or number of perimeters to resolve this no matter what printer you have. If you want a printer that can be customised you would be far better building your own from scratch. Then you get rid of the other Mini compromises ie direct drive extruder too hot for PLA, heated bed too cool for ABS, printed bed too small. Sounds to me like you are going to end up taking away all the good features of the Up (support removal) and end up with a crippled reprap.

As someone who build a reprap a month I get where your going but there is a reason I own an Up too.

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Michael_K
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Re: Custom MCU-module for UP! Mini...

Post by Michael_K » Tue Sep 17, 2013 9:42 am

roller wrote:No infill on thin walls is a result of the slicing algorithm and will happen in every slicer at a certain wall thickness. You need to jiggle wall thicknesses or number of perimeters to resolve this no matter what printer you have.
I would prefere another possibility, that you miss - improve the algorithm behaveour! ;)
And it's impossible with original UP.

The original UP hardware has all the parts (except of sensor) to control the bed temperature. It's a kind of mystery, why they don't use it. (In fact my personal feel of UP hardware - it's a professional full featured industrial-grade project, which has "not-so-good", limited implementation).
roller wrote:rid of the other Mini compromises ie direct drive extruder too hot for PLA, heated bed too cool for ABS
It looks for me just like additional mods - replacing extruder or adding the bed temperature regulator...
I think so.

You miss one detail - I can restore original UP anytime just replacing the module.
I will have the choise. For the price of small PCB (and it's not $1400, as you can guess ;) ).
(And you will have the same choise if I'll get some results).

May be you are right and the project will end up with my own homemade printer.
May be the project will even die (who knows). But now I'm quite optimistic about it.

roller
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Re: Custom MCU-module for UP! Mini...

Post by roller » Tue Sep 17, 2013 10:59 am

I never say don't attempt a hack because I myself am the kinda person who pulls something apart the first 30 seconds I have it to make it better... and my own reprap and CNC designs do not walk the much traveled designs.
I would prefere another possibility, that you miss - improve the algorithm behaveour!
And it's impossible with original UP.
With respect to algorithm behavior and infills you have it a little backwards. It's impossible with all FDM printers. The behavior you see is the result every different slicer has come to independently for one very good reason ... when the perimeters get too close together it is impossible to infill them without distorting the walls around them as there is insufficient volume - any infill will push on the walls and degrade print quality ... that's why no slicer tries to infill the very small spaces. There reason this changes from slicer to slicer is the width/layer height/volume ratio variations each slicer uses.
The original UP hardware has all the parts (except of sensor) to control the bed temperature. It's a kind of mystery, why they don't use it. (In fact my personal feel of UP hardware - it's a professional full featured industrial-grade project, which has "not-so-good", limited implementation).
The "original" Up actually does have a bed temp sensor ... the budget version, the Mini does not. The Mini doesn't because it's the budget version and you are right there is much room for improvement with the Mini. The Up printers themselves are not industrial grade ... they are the low budget, low production cousins to their industrial scale counterparts. The "limited" implementation does trump almost every other FDM printer out there up to $5000. The features they have taken away give ease of use. It takes me 5 minutes to teach someone to use the Up ... I get questions about how to tweak repraps for about 6 weeks after which time about a third of the people who get me to build them one have given up completely.
You miss one detail - I can restore original UP anytime just replacing the module.
I will have the choise. For the price of small PCB (and it's not $1400, as you can guess ;) ).
(And you will have the same choise if I'll get some results).
Sure, I am just saying for under $600 you can have a great printer with none of the limitations AND have your UP. Reliable prints with movable support (UP) AND print area, custom settings and great speed (reprap). Have fun with your hack but if you really want to get the most out of your Up look at how to reverse engineer the print jobs that are sent to it so you can mod the commands sent to the printer. The firmware itself is pretty dumb and just does what the software told it ... just like every reprap and CNC.

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Michael_K
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Re: Custom MCU-module for UP! Mini...

Post by Michael_K » Tue Sep 17, 2013 2:34 pm

roller wrote:when the perimeters get too close together it is impossible to infill them without distorting the walls around them
May be you are right. But there are still some questions and possibilitiers... Can we predict the distortion? What about distortion repeatability? Can we use thinner layer for thin walls (or whole outer perimeter like KISSlicer does) and thiker layer for infill?
I don't know. But I want to try.
roller wrote:Up printers themselves are not industrial grade
Writing "industrial-grade" I mean the solutions they use and my overall feeling. I don't think it's common for the homemade reprap zoo to have measurement channel autocalibration for example or 1/128 microstepping etc. In fact, sSome solutions look really strange for this application, like optocouplers on heater channels.

roller
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Re: Custom MCU-module for UP! Mini...

Post by roller » Tue Sep 17, 2013 4:29 pm

I don't think it's common for the homemade reprap zoo to have measurement channel autocalibration for example or 1/128 microstepping etc. In fact, sSome solutions look really strange for this application, like optocouplers on heater channels.
No, it's not common but most have been tried, or considered and deemed pointless or poor return for effort/cost. Optocouplers done many time, 128 microsteps ... no, don't think it's been done partly because the precision is well beyond that of other components and the torque becomes useless. I can go on. My main point being, if you want to be experimental why not go for an experimental platform than is going to offer you a greater variety of options to modify for improvement AND keep your Up so you can print you new mods for the experimental printer. I have retrofitted a laser cutter, a 3D powder printer and 3 CNCs ... in those experience I think starting from scratch would have yielded better results.

Anyway, I'm drawn into an argument of my own making and I don't know why because I don't really agree with myself. Give it a go - I'm am sure you'll learn heaps. You should also hang out on the #reprap IRC channel - you'll get lots of help testing your ideas. But at the end of the day I think you will find yourself with an inferior Up which really only needs a new heater module to make it a decent little printer.

twocycler
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Re: Custom MCU-module for UP! Mini...

Post by twocycler » Tue Sep 17, 2013 7:08 pm

I would be curious to try changing the ID bytes in the rom code for the model type. If you reflashed the Mini rom so that the ID was for a Plus, would it print with 0.15MM layer height? 8-)

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Re: Custom MCU-module for UP! Mini...

Post by roller » Tue Sep 17, 2013 11:40 pm

twocycler wrote:I would be curious to try changing the ID bytes in the rom code for the model type. If you reflashed the Mini rom so that the ID was for a Plus, would it print with 0.15MM layer height? 8-)
And would it get upset about the lack of temp feedback from the build platform? Of course if it meant you had to retrofit an Up Plus heater and sensor that would not be such a bad thing.

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Michael_K
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Re: Custom MCU-module for UP! Mini...

Post by Michael_K » Wed Sep 18, 2013 12:27 pm

twocycler wrote:I would be curious to try changing the ID bytes in the rom code for the model type. If you reflashed the Mini rom so that the ID was for a Plus, would it print with 0.15MM layer height? 8-)
I never planned reflash the original ROM. Anyway, I don't think that changing ID would change any printing parameters.

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Re: Custom MCU-module for UP! Mini...

Post by roller » Wed Sep 18, 2013 3:25 pm

Michael_K wrote:
twocycler wrote:I would be curious to try changing the ID bytes in the rom code for the model type. If you reflashed the Mini rom so that the ID was for a Plus, would it print with 0.15MM layer height? 8-)
I never planned reflash the original ROM. Anyway, I don't think that changing ID would change any printing parameters.
I think the suggestion was more that changing ID may let you flash with the Plus firmware instead of Mini firmware. A slightly more dangerous proposition for your original mainboard though.

twocycler
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Re: Custom MCU-module for UP! Mini...

Post by twocycler » Wed Sep 18, 2013 10:01 pm

Ding ding ding! Thanks Roller, it seemed to me that the software does an ID check and then enables another drop down menu option. Why make it harder than it has to be, right? Hardware wise I don't see any reason the Mini should not be able to do 0.15MM layers, but lacking capability this gives more justification to the now $750 price gap between the two.

roller
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Re: Custom MCU-module for UP! Mini...

Post by roller » Thu Sep 19, 2013 7:00 am

You are totally right in that it should be able to print 0.15mm. In fact both printers should be able to do 0.05mm but the reason they don't do that print reliability fall off at these smaller layer heights. Similarly, there may actually be a hardware reason for not going to 0.15mm on the Mini being the less rigid print bed. But you should be able to do 0.15mm and maybe print reliability might fall off a little. (Larger layers heights are better able to cope with inconsistencies/inaccuracy without generating a distortion in the print of a jam).

But as I was suggesting before, if you trick the firmware upgrade by changing IDs you are then going to have to trick the hardware to see the temp sensor on the bed of a Plus. Doable, just something to consider. I wish I'd taken photos of the Mini mainboard to compare to the Plus to provide more info.

If you are doing this for just 0.15mm though, I wouldn't bother. It's not that much of a difference and layer heights don't get noticeably until you halve that height.

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Re: Custom MCU-module for UP! Mini...

Post by JuliaDee » Thu Sep 19, 2013 1:50 pm

roller wrote:If you are doing this for just 0.15mm though, I wouldn't bother. It's not that much of a difference and layer heights don't get noticeably until you halve that height.
Depends on the part. On some very small parts I've done 0.15 vs 0.2mm has made the difference between usable and unusable.

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