Recently my son and I built the Robotic Arm Edge kit from OWI for a Science Fair.
There were a lot of parts and it seemed overwhelming at first, but once we got going, it was a lot of fun. First we separated the parts from their plastic carriers. Then we filed down the sharp pieces left sticking out from snapping the parts off.
Then we followed the easy instructions to assemble the gear boxes, motors, wires and the wired controller. It was good experience for my son (he is 8 years old). He mostly watched because at his age, the kit is a bit advanced. He learned how the pieces fit together, how the gears interacted, how the wires connected to the motors and to the controller. When the kit was complete, he learned how to control the arm with the wired controller.
It was a very good experience to build it and since the kit is very low cost, it was a fun afternoon project.
