This week:

Network:

Hacked some of my existing boards to try to run Neil's serial code. Looks like I may have cooked a board or have a loose connection -- the small one doesn't want to program this week. The working one seemed to be responding. Will look more when I have a little time.

Boards of the week:

This week I drew up some more motor control boards...

The first ones, I was going to use a compatible chip (DRV8811) to the A3977, but it may actually a compatible chip to the A3979, which comes in a much smaller package. Oops.
The wrong package

Then I made an adapter board for some older monolithic motor driver chips, so that I had something for the short term. They will be hooked to the microcontrollers with a ribbon cable, so I can swap back should I build an IC level solution.
I also relaid out the 8 channel MOSFET board with SMT logic level FETS. It is shown here, and should drive some unipolar motors.
boards of the week

Flexure Discussion:

As Neil suggested, I found and talked to a researcher about flexures (doesn't MIT have a researcher for everything). They work awesome for very fine positioning. Typically they use a force driven actuator... (i.e. voice coil/electromagnet). The downside is that the assembly is about 10x the size of the workspace -- i.e. a 1 inch cell would yield a 10 inch assembly. They sound cool, but I was thinking of stuff on the more macro level (inches of movement).

He also made interesting comments about how I might make various positioning assemblies (pros/cons of cable v.s. belt v.s. screw, and where to put bearings), and suggested making some air-bearings. Overall a fun conversation.

Final Project:

The Origional Grand Plan: Automate the world!

The initial plan was to build a toolkit of hardware/software for building machines. The idea was, since it was a toolkit, it should lower the bar to building various machines.

mechanical monster

Here is a sample of the parts I have around that I was thinking could be converted into a pick-and-place machine, cnc router, solder paster dispenser, or all of the above would manufacture a PCB.

Status:

Screws are ordered but won't arrive until late in the week. Don't have driver solution for large motors yet.
Large stepper motors is stimeyed by the small pitch parts... (htssop package)

Home stretch plan:

Reduce Scope: Look at completing the 3D scanner.

Todo:

Add axis for Z.
Fix USB-Stepper code to be more robust and spin the motors at stable speed.
Calibrate and fix geometry code.
Complete multiprocessor solution.
Figure out STL/output
Optional:
Build sexier stepper drivers
Make it do something else cool.