ZeroPi is based on official arduino zero but changed the mcu to SAMD21J18 to support more io pins.

ZeroPi stack on Raspberry Pi

Raspberry compatable plugin port

4 x SLOTs: stepper, dc-motor

2 x mosfet driver

2 x temperature sensor input

11 x extension genernal io or servo driver

1. Install Arduino IDE , version>=1.6.5
2. copy ZeroPi folder to arduino library folder
3. Download SAMD M0 support from arduino IDE->Tools->Board->boards managers
4. connect ZeroPi to PC and install drivers for Arduino Zero
5. upload demo sketch to the board, have fun :)