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BrachioGraph – the cheapest, simplest possible pen-plotter

brachiograph.art

1–10 of 51 posts

Re: BrachioGraph – the cheapest, simplest possible pen-plotter

#3

I've wanted a pen plotter for so long, but mainly to draw sharp geometrical figures. I don't think this would scratch the itch but I'm hopeful something will appear for <$100

Yes, I looked into this a few months ago. The cheapest I could find were 'robot' plotters that actually move across the paper. Not as accurate as I would like.

The alternatives seemed in the £100-500 ($120-620) range.

Re: BrachioGraph – the cheapest, simplest possible pen-plotter

#4
I think the big difference between this and the pen plotters I used for many years is that the latter can lift the pen. Even so, I could not take my eyes off the video of this little toy thing scribbling away so diligently. What a clever thing this is.

PS. the old calcomp I used back in the early 80s was quite fun to watch. For one thing, the motors were so strong that they shook the table upon which the plotter sat. For another, graphical terminals were quite rare then, so often you didn't know what the plot would be like until it started to be drawn.

Re: BrachioGraph – the cheapest, simplest possible pen-plotter

#5
I wonder how this compares to a two-wheel plotter; I saw one of those demoed and it made surprisingly crisp drawings for how simple it was.

If you're not familiar, take an inclined drawing table, have a wheel at each top corner with cable (or string) running to the pen, making a triangle. Using a servo to retract or release the cable will change the length of that side, moving the point of the triangle. The one I saw had a simple spring-loaded solenoid for lifting the pen.

Biggest downside is speed is limited by how fast gravity can keep a releasing cable taut.

Re: BrachioGraph – the cheapest, simplest possible pen-plotter

#6
"simplest" in the sense of the simplest bill of materials, but definitley not a simple path towards plotting an image. Anyone who's tried to build one of these and actually have it plot reasonably well will know that it's super fiddly to get working.

I'd save my time and just buy a proper axidraw, if you actually want to plot anything.

Re: BrachioGraph – the cheapest, simplest possible pen-plotter

#7

I think the big difference between this and the pen plotters I used for many years is that the latter can lift the pen. Even so, I could not take my eyes off the video of this little toy thing scribbling away so diligently. What a clever thing this is. PS. the old calcomp I used back in the early 80s was quite fun to watch. For one thing, the motors were so strong that they shook the table upon which the plotter sat.…

This lifts the pen, you can clearly see the third motor at the very tip that's using a white piece of plastic to lift.

Re: BrachioGraph – the cheapest, simplest possible pen-plotter

#8

I've wanted a pen plotter for so long, but mainly to draw sharp geometrical figures. I don't think this would scratch the itch but I'm hopeful something will appear for <$100

I would recommend a Cricut machine. Far less maintenance and everyone in the family can use.

Re: BrachioGraph – the cheapest, simplest possible pen-plotter

#9
I built the brachiograph a few years ago. I wanted to show my kids (8 years old and 6 years old) cool things the could build by plugging a raspberry, some servos and readily available materials. We were impressed on how good we could reproduce one of those shopping mall cartoons of my daughter. It was a fun build.

Re: BrachioGraph – the cheapest, simplest possible pen-plotter

#10

I've wanted a pen plotter for so long, but mainly to draw sharp geometrical figures. I don't think this would scratch the itch but I'm hopeful something will appear for <$100

I would recommend a Cricut machine. Far less maintenance and everyone in the family can use.

For the HN crowd, I'll suggest an AxiDraw over Cricut. Cricut tried adding a subscription fee just for people to continue to use the machines they already bought[1]. It was reversed over public outcry, but the fact stands that they're capable of bricking your machine with a dumb policy decision.

The AxiDraw has a high build quality, and you can use their open source software to drive it or other software that uses their published USB spec. EMSL are good people, but even if they weren't, they physically aren't able to remotely brick a machine once they ship it to you.

[1] https://www.utahbusiness.com/cricut-announced-a-new-subscrip...

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