Four Degrees of Freedom Lego Robot Arm Made From Two Thymio Robots

This 4-degree of freedom robot arm is made from two Thymio Robots and plenty of lego.  The small lego wheels rotates in front of the proximity sensors to measure actual distance traveled.

This robot arm was created by: Dr Stéphane Magnenat of EPFL, and Austin Hendrix of Willow Garage
More information about the Thymio robot can be found here.