Arduino Mega 2560 R3 Drop in T-Nut for V-Slot Aluminum Bar (5mm) It has 54 digital input/output

It has 54 digital input/output pins (of which 14 can be used as PWM outputs)

both the output transistors are turned off presenting a high-impedance state to the bus line

4 mm hole permits more precise filament extruding without jamming

Instructables detailed tutorial Wiring 3D Printer RAMPS 1

Note: the middle 4 pins (GPIO0

Arduino Mega 2560 R3 Drop in T-Nut for V-Slot Aluminum Bar (5mm) It has 54 digital input/outputThe Mega R3 is backwards compatible with the arduino mega same driver, same uploading, same look and work with the existing shields but can adapt to new shields. Description The Arduino Mega 2560 is a microcontroller board based on the ATmega2560. It has 54 digital input output pins (of which 14 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header,