Lego Motorized Robotic Hand
From a distance it may look like a regular robotic arm. Get close up though and you’ll see this robotic claw is made entirely using LEGOs. This is no kid’s project though, it’s an attempt at a functional likeness of the human hand. To replicate the human movement, power is fed through hoses from an external pneumatic compressor.
Manual dexterity comes from four movable fingers with two joints each and a thumb which can be bent and raised or lowered. The 4-motor, 4-valve pneumatic hand goes through the full range of hand movements from moving joints to rotating wrists. Believe it or not, this entire LEGO project was built in just over a weekend. It can grip any object and also give a thumbs up quite easily!
[Source] Hack n Mod - Complex Robotic Hand Built using LEGOs