What follows are preliminary notes during the build of the __[KRZ03]__, a Mechanum-wheeled robot. It uses parts from the [KRZ01] and [KRZ02] robots and therefore supercedes (replaces) them. Its Raspberry Pi Zero W, Mini Black Hat Hack3r, and a pair of Picon Zero motor controllers were used on the KRZ02. After contacting 4Tronix, they sent a customised Picon Zero that uses a different I2C address so that it's possible to use two on this robot without bus contention. A simpler alternative would have been to use the PiBorg [ZeroBorg Motor Controller|https://www.piborg.org/motor-control-1135/zeroborg], which has four motor controllers as well as a 1.5A regulated power supply. [{Image src='attach/GPIO/raspberry-pi-pinout.png' width='600' link='https://pinout.xyz/#' caption='The Raspberry Pi GPIO Pinout (courtesy pinout.xyz)' align='center'}] ---- [{Tag Robot RobotPrototype KRZ02}]