RoboSketch - Propeller controlled Etch-a-Sketch

JasonDorie

While this is much simpler than Mike Park's PropEtcher (see http://www.youtube.com/watch?v=MgyZgqImAHA) it was as much a test of my CNC machine cutting acrylic as it was making an automated Etch-a-Sketch.

The circuit is incredibly simple: it's a Protoboard and a single darlington array to control a pair of unipolar stepper motors (the ones Parallax sells here: http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/stepper/List/0/SortField/4/ProductID/65/Default.aspx)

I used my home-built CNC router to cut the face plate and gears from a single piece of acrylic and replaced the existing red frame with my new CNC'd one.

The software is written entirely in SPIN and supports a simple "goto" function that takes an X & Y coordinate. It uses a Bresenham line algorithm to control the step rate of the motors. With gearing and using 1/2 steps, the usable screen area is about 800 x 600 units.

Here's a video of it in action: http://www.youtube.com/watch?v=W3iPjJfIIOs
...and another of it drawing the Hack-a-Day logo: http://www.youtube.com/watch?v=-MNqW1GT4nc

Code is attached.

PJAllen

Dorie, you've done it again!

(Show it making the Spirograph pattern.)

RonP

Nice work Jason.

Does this mean your back to writing code for Quadracoppters? Joking of course.

Ron

JasonDorie

PJ - Better still - I made it draw a skull & crossbones... er, wrenches. It's the Hack-a-Day logo.

PJAllen

Super.
It's a cinch to get on then.

PJAllen

You did it!

http://hackaday.com/2011/08/05/etch-a-sketch-automatically-draws-a-tribute-to-hack-a-day/

JasonDorie

I sent it to them - I figured drawing their logo would help. It's interesting to see the other ones that have been done in the past.