One of my ongoing projects (I started it when I was about 15 years old with an aluminium one) has been a robot hand but only recently have I been able to easily make something that will control multiple hobby servos. Hooray Arduinos!
Seen to the right with attached sword :) Note also the wrist joint swivels, make by forcing metal around a pipe and bolting stays onto it.
I do not know exactly what has make me want to create something like this but I do believe the movie Terminator and the anime series Bubblegum Crisis helped:
When I reliased it was now possible to make something to control 12+ servos I started building... in cardboard.
In this image you can see the finger linkage between the first segment and the third segment:
After moving to ABS plastic this is the result:
Unfortunatly the linkage is slightly off due to user error so the tip segment does not have the range of movement I would like but as its not hooked up as yet it can wait. This image shows the movement of the twin linkage of the first knuckle. Note the 'Polymorph for the knuckle (uni-joint):
And a video of the early knuckle movement:
Below you can see how the linkages and spacer/brackets work (Polymorph rocks) :