After convincing my son to let me destroy _upgrade _his toy robot, I was quick to order a bunch of Arduino-related gear online. A month later and “Bingo” is still sitting in pieces, but when the parts started arriving last weekend I was able to make a minor breakthrough: I installed the Arduino …

This weekend I finally convinced Jules that we should take his robot apart. Admittedly, he might have been less enthusiastic if Agent Bingo didn’t already need surgery — one of the DC motors in her legs had stopped working, so the poor thing could only walk around in circles. “Don’t worry,” I …