In the middle school technology lab I facilitated, we used to have a station with a FischerTec building set. For those of you who have never seen these kits, it is kind of like Lego on steroids. I am told that it is often used by engineers to prototype mechanical designs.
Anyway, I would often get someone who wasn't excited about any of the projects they were asked to build with the fancy FischerTec blocks. They would whine and complain:
Whiny Student: "Mr. G, all this stuff is too easy. I've been building things since I was two."
Wise Old Tech Teacher: "OK. Build a working hand."
Whiny Student: "No problem! I'll have it done by the end of the hour."
I'd come back the next day and usually they were stuck and would say, "This is harder than it sounds." They would have a jointed hand but couldn't make it grip. We'd talk about how a human hand works and maybe look at a few pictures.
Wise Old Tech Teacher: "Try again. Only this time, just make a working finger."
I had kids come after school to spend extra time on that assignment. A few came close. A couple of young men got a finger they could control with a motor but weren't able to get a whole hand built.
I saw this video the other day and thought if this had been available for my kids, they would have solved "the finger challenge" in no time. The walls of my classroom would have disappeared and my students could have built off what others had already done.
Written instructions and diagrams can be found here.
[Image:"Simple Animatronics (robotic hand)." Instructables. 01 Jun 2007. Instructables. 11 Oct 2007