A programmable robot arm that can pass ... Both arms can be customized for a range of tasks, from the silly to the sort-of practical. They can be hooked up to a Leap motion sensor for gesture ...

The usual go-to when building a simple robot arm is the ever-pervasive ... but if strength is not needed a stepper motor would provide much better motion in the same price range.

Part of the “special sauce” that makes this arm so capable is the custom optical encoders ... [Adam]’s robot arm able to move incredibly smoothly throughout its range of motion.