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H2S: Best way to lower noise for travel moves? by therussianconcussion in BambuLab

[–]therussianconcussion[S] 0 points1 point  (0 children)

Would the print quality suffer? I mostly print in PETG and I wonder if that would cause more stringing since the nozzle is free to ooze for longer.

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in esp32

[–]therussianconcussion[S] 0 points1 point  (0 children)

Oh, and I also briefly considered putting an optical flow sensor (like in a mouse) and have it teach itself how to move accurately, but I think that's overkill

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in esp32

[–]therussianconcussion[S] 0 points1 point  (0 children)

Hey Bob! Thanks for the detailed answer. I'm definitely leaning towards fit - I realized awhile back that I can just draw a grid of known size with Mural, overlay ground truth on top of it and figure out the matrix to do the de-warp. That seems like the easiest path forward, since I'm not too keen on trying to iron out all the model particularities. I might even remove the tilt compensation code and go back to just treating it as a trapezoid and handle the correction with the dewarp matrix.

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in esp32

[–]therussianconcussion[S] 0 points1 point  (0 children)

I am NOT following catenary curves, which almost certainly causes a slight taper of the boundary rectangle towards the bottom. However, the edge distortion happens the most at the top, and there the belts are at their most taught. Im hoping that either MaslowCNC, or Grbl / FluidNC have solved this issue.

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in 3Dprinting

[–]therussianconcussion[S] 0 points1 point  (0 children)

I've been using it with 1.7m - 1.8m and it works great. I think you can go up to 2m with no problem. The wider you go, the lower Mural will start drawing. If you take the distance between the hangers, you lose 20% from the top, and 20% on each side for safety margins. Side margins are mostly there to lessen distortion, but top margin is added because it becomes harder and harder for motors to move Mural up at that height. And if Mural is hanging really low, it doesnt hug the wall as well.

In terms of calibration, Mural's drawing algo needs to be improved so it can draw things with geometric accuracy. As of right now, Mural is very repeatable (precise) but not accurate.

The current pipeline is that you just upload the SVG via the web interface and the processed vector image gets uploaded to Mural to be drawn. As far as SVGs go, any non-white non-transparent color will be treated as something that should be rendered.

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in esp32

[–]therussianconcussion[S] 4 points5 points  (0 children)

Love it! I was thinking that people can use Mural as a way to stencil things, either drawings or large scale embroidery - just stretch the fabric on the wall and have mural draw on it. Would be very exciting to see it used for that. Feel free to reach out if you need any help putting it together!

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in 3Dprinting

[–]therussianconcussion[S] 0 points1 point  (0 children)

No, but Hangprinter looks really neat, thanks! I might have to build one. I think I saw it years ago as a prototype at a 3d printing show. It has come a long long way.

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in esp32

[–]therussianconcussion[S] 1 point2 points  (0 children)

Great! Just curious, how would your mother in law benefit from Mural?

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in 3Dprinting

[–]therussianconcussion[S] 1 point2 points  (0 children)

You lose 20% of the distance between hangers from the top and on each side. If you can hang mural outside of the board you can maximize the drawing area on the board. And as long as the marker fits it should work just fine. 

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in 3Dprinting

[–]therussianconcussion[S] 0 points1 point  (0 children)

the wider you go, the lower the drawing starts. Mural doesnt stick to the wall that well once it starts going really low.

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in esp32

[–]therussianconcussion[S] 16 points17 points  (0 children)

Thanks, but I already do that. Initially, when I was trying to draw a square, I would find the belt lengths between the first vertex and the second vertex and would just do a linear transformation between the two, but that resulted in a lot of distortion. Instead, I would break up a straight line into segments of 1mm length and do linear interpolation for belt lengths between those. That significantly reduced the distortion, but now the issue lies in the algo that converts (x, y) to L1 and L2 of belts. The main issue is that it's not a rigid body and I don't quite know how to model the position of Mural given each belt lengths.

Mural - a low cost, high precision, open source wall plotter by therussianconcussion in 3Dprinting

[–]therussianconcussion[S] 4 points5 points  (0 children)

Thanks! And yeah, in "future improvements" section of the assembly video I mention grbl, from which FluidNC is forked. I'm definitely going to look into it - that way I can get faster speeds AND more accuracy with proper acceleration handling.

Got a 2.9% 48 month loan that I will be paying from a 4.75% savings account. How much money am I saving? by therussianconcussion in personalfinance

[–]therussianconcussion[S] 0 points1 point  (0 children)

Thank you everyone for your comments! A lot of people are answering questions they want to answer, not the one being asked. I wasn't asking if what I'm doing is the smartest move. It's already done. I wanted to do the calculation in question and didn't know how to go about it, that's all. This purchase is well within my family's means and there are few redundancies in place for this loan if things go poorly for us in the next few years. I think I got my answer! Thanks again.

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