Nice work here from Dan Royer – including a very clear and illuminating write-up of the maths behind hanging-v plotters and this grand acceleration / movement scheme.
His code looks like it could be more efficient and elegant than mine, and its clarity is refreshing, so I’m interested in either adapting it, or just using it outright. Prompting me to think about moving to a g-code based language too – it kind of does make sense. Just not sure how to deal with the dual coordinates system (native and cartesian).
No impressive results in terms of actual drawings on the site, but have a dig around and there’s some really nice stuff.
Why use two coordinate systems when you can use one? Just adapt your drawbot to use the same coordinate system as the gcode. By all means, go ahead and use the software. If you can help me with pen up/down that would be awesome! I’m also looking to auto-calibrate. If you or one of your readers is interested, please come check out my website and say hello.
I really like the native coordinates system – it’s what makes it a polargraph rather than just a cartesian bot, and for fills and shading and stuff, using the native system is quick and honest. It shows the real bones of the machine.
Auto calibration is the dream. I’m planning on big beads a fixed distance from the gondola and a calibration on startup that winds in each spool until the beads hit a switch. I’m going for cheapness rather than elegance. I would like to be able to do proper width calibration too, but I think simple measurement for that one is probably enough.
BTW, I put up some samples that were all done over the weekend at the Seattle Mini Maker Fair. http://www.marginallyclever.com/2012/06/drawbot-the-seattle-mini-maker-fair/