Thanks for the reply.
I'm making slow progress on the rewrite of the arduino (not because I'm slow, but because I don't put into it as much time as I'd like to), with basic functions like "rotate x degrees", "do a sad sound", "go to position x,y", etc... so a kid could code some motion into the device by stacking orders. My son loves when I tell him I've taught the device new moves, he's having fun, I'm having fun, which is what counts.
Running the Pi proves harder. I don't know the board very well, and I haven't spent a lot of time trying to learn about it either. Not yet at least. Might do that when I have some time on my hand. I can make the robot move, run the LEDs, pretty much reproducing what I can do with the arduino alone. But that's not why the Pi was added to the bot ! I want its brain to wake up, I want to be able to say, on a stormy night, "now rise, and walk !".
Sample code works well, but as soon as I pretend to understand how the communication bus works, it just shames me to death by quasi systematically refusing to do what I thought I had asked it to do (often by doing nothing at all, actually). So a step by step tutorial on how that works would be a great booster, in my case.
Likewise, I've thought I could easily connect the Pi to my computer to be able to run it through WIFI with the keyboard and the video on screen, but that proved way above my level of understanding on how that works...
Okay, that's not may area of expertise, but that's just the point, I want to learn about it. Here again, having a tutorial that describes how to build a rock solid communication link between the Pi and a computer or an iPad, would be great help to me.
Maybe that's already available on the internet ? I don't know, haven't found one yet. Then again, I haven't commited a whole lot of time on that either, so don't worry too much about it.
Anyway, i'm still having a lot of fun with the arduino, but I'd really like to get to master the Pi as well. I read of people who've coded some image recognition features into their Pi, and that makes me think of a number of cool things to do with that much power on a robot like Spirit... including some that the Cozmo does right out of the box... (my son tells me that Cozmo says his name when it sees his face