1) Carbon panelled twin wheel skateboard

 J Dingley.  email:      self-balancing-skateboard@sky.com
May 2010. Batteries all hidden inside the hollow deck.
Shorter than previous build, more rounded ends, still controlled via wireless Wii Nunchuk. Probably as far as I can take this now apart from moulding the whole thing in carbon fibre!
Upgrades will be confined to software - better steering "feel" on corners and so on.
 Self balancing skateboard carbon 1
 Self balancing skateboard carbon 2
Video of myself and others riding it all day long in a street carnival in Oxford July 2010, the "Cowley Road Carnival." Battery still showed full charge at end of the day on the LED display and took just 2 hrs on charger to genuinely bring it back up to full charge.

YouTube Video

 Self balancing skateboard carbon underside
 Self balancing skateboard carbon, carrying handle
 Self balancing skateboard carbon with wireless nunchuck
Self balancing skateboard carbon deck opened: 88 LiFePO4 cells. The battery management circuit board was in the deck (which is why old one was longer). In this one it is under the main deck.
Nearly finished
 Self balancing skateboard carbon, view of griptape
UPDATE 2012:
In the end I merged this with my pneumatic tyre version. Ended up a bit bigger but the combination of long battery life from the deck full of batteries, plus the pneumatic tyres for rough surfaces proved worth making these changes.
Tip: Using a vacuum cleaner when cutting (dremel disc) carbon fibre is very good idea as fibre dust very nasty. However, don't use a Dyson, the carbon particles do get through the cyclones and do get into motor which then emits clouds of smoke, sounds very sick, then stops - forever!