This is a small motor made from simple household supplies. A battery pushes current through a coil of copper wire under the influence of a permanent magnet. The coil spins freely when operating.

A loop of wire rotating between two permanent magnets generates DC and AC signals. This device can be connected to a DC power supply to run as a motor. Disconnect the DC power supply, if applicable.

YOKOHAMA—Nissan Motor Corp. showcased experiments with self-driving cars on city roads to the media at its headquarters here through March 10.