Monday, March 26, 2012

Last bugs worked out

I've posted a couple of pictures for comparison. The first is an SVG file as rendered by Inkscape. The second one is a photo of the same SVG as drawn by my drawbot.

Thursday, March 15, 2012

Pen Carrier Upgrade Goes Live

Here's a still of my pen carrier with the up/down mechanism installed, wired, and working, and here's a video sample of the bot doing its very first drawing with the new hardware. I'm sorry for the watermark on the video. I need to find a good free video editor.

The actual drawing is an .svg file done in Inkscape. It's a path tracing of a bit map image I found on Google images. If you'd like to have the bot do a drawing for you, send me an .svg (everything must be a path) and I'll send you back a drawing.

Sunday, March 4, 2012

Further work on the Drawbot

Recent work on the drawbot has been following three parallel lines:
  • First I'm working on a little servo driver board to control a pen up/down mechanism. I've got the electronics and code working, now I'm building the actual mechanism. In the first version I'll run power and comm through wires up to the pen carrier. I just got some wireless transceivers from Sparkfun, so eventually the pen carrier will hold batteries, electronics, and the mechanism, and control will be wireless. That way I won't have to cope with the mass and drag of wires.
  • Second, I've rewritten my command protocol to less primitive and more robust. The boxes and pen up/down electronics all have the same address when initially programmed. Now I've got a command protocol where I can readdress the hardware and it will keep the new address in flash memory when powered down. Right now it's not such a big deal, but in the future this will allow me to very quickly reconfigure the drawbot (i.e. adding axis, other carrier controls, etc.) on the fly.
  • Third, and probably the most fun, I've been creating a bunch of drawings in Inkscape for the bot to draw - and at the same time debugging my .svg reader. The bot will draw simple .svg files now, and I'm working slowly through the details of Inkscape's implementation of .svg and learning the math to draw cubic spline curves with the bot. The image above is one example of the Inkscape work I've been doing. It's a drawing by daVinci - vectorized and cleaned up a bit.