After a long lead up, this is the PolyBot Raspberry Edition. Reduced production cost, increased accuracy.
This thing is a bunch of modifications to the first PolyBot design from 4 months back. I wanted it to be my 100th design, and so it is.
The essential design remains the same, it is a delta robot housed in a tetrahedron frame. I have experimented with many tetrahedron frames over the past few months. The one presented here is based on the vinyl tubing vertices: http://www.thingiverse.com/thing:8306
There is heavy usage of zip ties as well. These have proven to be as strong as any other fasteners, and you simply can't beat the ease of use, or price.
It also uses the modified servo mounts, and improved male/female clevis pieces. The way the pieces are designed, there is very little wiggling around, so the arms are fairly rigid in their motions.
I have included all the plastic pieces here in one place for easy download/print.
I have also uploaded a massive collection of photos, and even a rudimentary instruction manual. If you look carefully, you'll notice the Arduino Sketch in the 'code' directory (wiidemo). There is also an 'Alternates' directory which contains various other odds and ends like a different effector base, options for vertices (using ball/socket if you prefer).
I have had my wife build this thing a couple of times now, and it goes together in a couple of hours, once you have your plastic parts printed.
Also of note, there are tighter tolerances on parts this time around. I've used nice steel pins for axles, and brass sleeve bushings in places for 1/4" steel pins to rotate. Nice and smooth! Although everything is pressure fit, and stays in place nicely, I've used some nuts and screws on the servo mounts to make them extra sticky.
Just a lot of little improvements here and there. The instruction manual is actually for a socket/ball joint based frame, but for the most part it will apply to any tetrahedron you choose.
Enough words... On to the files.
UPDATE: Some blog posting to go with it...
1) Download the monster sized delta-raspberry.zip file. It contains pictures, source code, instructions, .stl and .scad files
2) Look at pictures, look at parts. The documentation tells you which McMaster-Carr parts to order, as well as some AdaFruit electronics, and miscellaneous stuff.
3) Build your tetrahedron frame
4) Cut your plywood platform and base pieces
5) Print your plastic parts
6) Assemble everything
7) Plug in some electronics, and a Wiimote
Really I have a lot of work to do on the documentation, but you actually should be able to assemble just by looking at the bits and pieces, and the pictures. If not, then I've missed my design point. Usually parts will only go in one place, so it shouldn't be very easy to do things wrong.