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Using a projector as a cheap CNC alternative

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keyboardstu

Using a projector as a cheap CNC alternative

Hi all,

First time posting (only just learnt about LibreCAD)

I am wondering whether it would be possible to project DXFs onto plywood using a standard projector, trace the lines and jigsaw them - as a cheap alternative to CNC.

It would be necessary to calibrate the image to compensate for any distortion of the projection. You would have to project a grid (maybe 5 x 4 points), then measure the distance between the points and input those measurements back into the software, in order to re-project the DXF as a calibrated image.

Could this be a plugin for LibreCAD? It would be a simple UI and I imagine a layer quite close to the Graphics HW to use a graphics distortion API.

I'm not a coder, but think this would be useful if anyone fancies giving it a go!

Thanks, Stuart

R. van Twisk

Re: Using a projector as a cheap CNC alternative

Administrator

you could also print on transfer paper?

I don’t think that a project is much usable for anything that is a bit bigger due to the accurasy of a project..

If you are more info organic shapes this might work though.. Just make sure you mount the project 90 degree above your workspiece.

If you really need calibration I can imaine more then a few points are needed.

Ries

On 20 Feb 2019, at 08:43, keyboardstu [via LibreCAD] <[hidden email]> wrote:

Hi all,

First time posting (only just learnt about LibreCAD)

I am wondering whether it would be possible to project DXFs onto plywood using a standard projector, trace the lines and jigsaw them - as a cheap alternative to CNC.

It would be necessary to calibrate the image to compensate for any distortion of the projection. You would have to project a grid (maybe 5 x 4 points), then measure the distance between the points and input those measurements back into the software, in order to re-project the DXF as a calibrated image.

Could this be a plugin for LibreCAD? It would be a simple UI and I imagine a layer quite close to the Graphics HW to use a graphics distortion API.

I'm not a coder, but think this would be useful if anyone fancies giving it a go!

Thanks, Stuart

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dellus

Re: Using a projector as a cheap CNC alternative

In reply to this post by keyboardstu

Like Ries I do not think this idea is very promising, but if you want to carry it on it might be a possibility to export / convert the drawing to a bitmap. In pixel-graphical programs tools for distortion compensation do exist. The projector only has a limited resolution anyway.

jose

Re: Using a projector as a cheap CNC alternative

In reply to this post by keyboardstu

Hi All,
I have been thinking the same way, I work in a counter top granite company y all the time I must mark the cutting piece (I am a sawjet operator) according to a set of colors in a dxf file printed on paper. I just order a mini projector to try to project the CAD lines as a bitmap file and mark them prior to be cut, I just need to see the lines or outlines of the final layout on top of the granite slab. I have searched on google and there are laser projectors for that but the cost in the thousands of dollars is too much for the simple task I want to perform.

keyboardstu

Re: Using a projector as a cheap CNC alternative

Hi there, I'd be interested to know whether it works for you, and whether you have to calibrate for distortion at all.

Thanks, Stuart