The PowerPad provides regulated power to the STRUIX stack. It can supply up to 1A at 3.3v and also terminates the I2C buss. It even has built-in reverse polarity protection. Connection to the main unregulated power supply (6v to 18v) is made through a screw terminal block.
Perimeter pad holes are set up for stacking with M3 hardware.
This board is open source via Creative Commons license. Eagle PCB files for this board are located in the attachments section on this page.