Do you need a combination of sensors, slots, encoder motors, servo motors and stepper/DC motors for your projects? Check out ZeroPi! With this solution you can connect 11 micro servos and 8 DC motors at a time!
The ZeroPi is essentially an Arduino Zero compatible development kit for robot drive systems that uses Atmel SAMD21J18, 32-bit ARM Cortex M0+ as the MCU, and it is also fully compatible with Raspberry Pi.
ZeroPi measures 6cm across and features several channel interfaces, including a4-channel SLOT, 2-channel Temperature Sensor and 2-channel MOS driver output.

The ZeroPi board also features extension pins for Micro servos and sensors, Serial Wire Debug (SWD) interface and USB host/device. The Raspberry Pi connector is ready for plugging in a Raspberry Pi. There is also an M3 and M4 holes on the ZeroPi board (the M3 hole is compatible with Raspberry Pi and the two M4 holes are compatible with MakeBlock aluminum parts) to support open source hardware projects.

The makers of ZeroPi also successfully ported the Marlin and Repetier firmware to ZeroPi for I3 and delta open-source 3D printer, so now you can directly control the 3D printer with a ZeroPi without an expansion board (the 3D printer is 4x faster and smaller in size than Arduino Mega 2560 3D printer, and costs less too). You can also connect a web interface to remotely control the 3D printer using Raspberry Pi and control everything by using your browser during printing.

See more at:

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• Add FPGA and Arduino Headers to the Raspberry Pi and Beaglebone Black
• Raspberry Pi GPIO Servo Control Without An External Controller! 
• Fastest Way to Build and Program An Arduino Robot Car Wirelessly!