Aux Power Board
The power board was built by Bret Victor. A standard connector from a
switching power supply plugs into it, and it provides ports for other
boards to plug into. The left row of ports is +5V and ground, and the
right row is +12V and ground.
All hardware boards that draw any significant amount of current should
get their power from this board, through appropriately thick wires. It is
okay for boards that pull very little current to get their power through the
I/O port.