Tuesday, November 20, 2007

One Laptop Per Child

I'm lucky enough that I already have one of the OLPC XO units to play with. They're pretty awesome and I think they'll catch on like wildfire. It occurred to me that cities could, in return for providing OLPC machines to children, ask them to help with some simple neighborhood clean-up type tasks. Most parents I've asked have thought this was a good idea. Do you? Please let me know. I'm toying with the idea of approaching the mayor of my city with this idea.

Visit Laptop.Org

Monday, November 19, 2007

Lego Mindstorm NXTs

EDIT:  EV3 Units available for sale, end-of-september 2013!  Linux-based Programmable Brick!

LEGO Mindstorm NXT robot kits absolutely ROCK!

I recently bought the latest NXT kit - $250 is a little steep,
but it turned out to be worth every penny.

It comes with only three motors... that's odd... ( ob. bad math joke :-)
-> not four (one for each of the four wheels on a car).
-> not six motors (for the traditional six-degrees-of-
freedom x,y,z,yaw,pitch,roll tooltip model)
...but just three motors. What to do with that?!?

I did some research and learned about holonomic drives and about killough platforms.
Since they use three motors they're ideal designs that'll work with the parts from
just one NXT set (a noble design goal for obvious reasons.)

These are pretty neat - they're triangular platforms capable of accelerating in ANY direction, regardless of its current orientation, and capable of changing/controling the platform's orientation (i.e., indirectly, sensor orientation), regardless of what direction they platform is accelerating in.

This is really useful for line-tracing and other types of goal-seeking robotic control. The same control loop manages both the orientation vector and the acceleration vector of the unit... meaning it can move around while aiming a camera at a fixed point, for example.

Design issues:

how to get the a reasonably low c of g?
How to mount the motors so they can't come off?
Where to mount the controller?
What should the wheels look like?

Control issues:

- bluetooth from the blackberry? How hard?
- clap-on/clap-off easy enough
- various hunting modes

This is all still very much a work in progress... I welcome your input!
-Paul