Goal: a desktop cnc machine Level: Beginner

[kryton9]

John, I don't think you need any motors. From the exciting photo of Athena standing with a walker, it looks like she just needs a safety system to support her in case she starts to fall.

You could just run steel cables 2 in parallel (orange) and then a third cable (green) perpendicularly to the other 2 (see drawing). Then Athena could be safety harnessed to this third cable (blue) giving her total free x y movement.
Inside, I would make sure to eye bolt into studs in the walls. Better yet, put a 2x4 between 2 wall studs and put the eye bolt into that in new between stud. For the harness connection to the third cable(green) you would need a strong swivel connector giving Athena 360 turning ability. If you could find a swivel connection that can disconnect quickly, then you could have this sort of rig in the rooms she would like to use. The parts for an entire room are probably under $50.

Outside you could use poles to support the 2 parallel cables giving her outside access with safety.

The (green) cable would move left to right (lets call this X movement) in the room along the (orange) cables. The (blue) harness would move in the perpendicular direction (Y axis) along the (green) cable. With a swivel connection she could also rotate freely.

rigIdea.png

[kryton9]

Your post was relevant to using motors and control systems, besides it came with good news of Athena's progress to boot!

[Shaun]

I ordered the nerdkit today. For trying to learn this stuff, it was a good fit for me. I plan on trying all of these kits eventually, as they seem like a good value for the fun they can provide along with education.
http://www.routercenter.com/

[kryton9]

One thing I realized in playing with my NerdKit is that there is so much more to electronics than just putting things together. You really need to become an electrical/electronics engineer to really use the nerdkit.
I found myself wandering off to reading up on things way over my head and too much new stuff to absorb and retain.

The Arduino is more for us who want to use this technology without having to become engineers.

But since my end goal was to make a cnc to make robotics, the world has changed so much since my first post that now you can get robot kits and get right to the fun stuff without having to make everything by hand.
I don't mean the simple hex bug like robots but robots with motion, sensors and communications. Really no need to build a lab anymore if you want to get into this stuff.

Here are just a few.

http://adafruit.com/products/1006

http://kits.makezine.com/category/robotics/ page 2 has some cool stuff too.

https://www.sparkfun.com/products/11074