[angusp]

It's fine with a reasonable amount of weight - I'd have to ask Sandy how much weight Marty can take before he physically can't move, but a touchscreen should be fine, and won't disrupt his walking ability much. Of course you could re-plan his walking with the weight taken into account, but that's quite complex. We'll probably have standard mounting holes on top of his head, so should be a nice and easy hack :D

[asimuvPR]

If you keep answering I'll keep asking! :)

How many degrees of side-to-side motion can the frame take before it falls down? I'm thinking of getting two of these, putting a touchscreen on each one, and having them play joust. The objective would be to touch a dot displayed on the other players touchscreen. The things I come up with...

[angusp]

Well I like the sound of getting another one...

By side-side motion I'm guessing you mean a tipping force - and the the answer would be that he's pretty hard to shove over, at the limit of his lean he's stable, 10 degrees tilt and he'll fall. From fully upright, you need a bit more of a shove - having just pushed one over. Sandy says they can tip themselves if you wobble fast enough.

We're guessing you were thinking of something like this --> http://i.imgur.com/Cmmwu5A.jpg

[asimuvPR]

Yes, exactly. This platform is very affordable and would make a great introduction to a sumo-type robot competition using bipeds. But not shoving robots around a la RoboOne, but hitting a target drawn on a touchscreen. Its something Ive been tinkering about for a while.

I appreciate the answers. Best of luck with the project!