Instructables Sister Company on BBC Answered
Squid Labs spin-off company Potenco is cropping up quite a bit on the BBC website at the moment, snugly amongst the fuss about the latest "Get 1 Give 1" project by One Laptop Per Child (they're working with Amazon now).
The pull-cord generator (called a yo-yo generator by the BBC) is shown as an integral part of the OLPC system.
BBC Video (may not be viewable outside UK)
Get 1 Give 1 Story