RepRap Arduino Mega Pololu Shield, or RAMPS for short, is designed to fit the entire electronics needed for a RepRap in one small, but powerful package for low cost. RAMPS interfaces with the powerful Arduino MEGA platform and has plenty room for expansion. The modular design controls the movement of the 3D printer, 2 x extruders, 2 x hotends and a heated bed while sensing the temperature of the hotends and heated bed. Additionally, a number of Arduino expansion boards can be added to the system as long as the main RAMPS board is kept to the top of the stack. Most popular expansions include a LCD display, SD card reader, a cooling fan or two and a second extruder.

You will need the Arduino MEGA 2560 controller to be able to use the RAMPS 1.4 board.

Connection diagram: