Re-ARM - 3D Printer Control Board - EXRA3D

• Specifications for use in 3D printer
  • Control of 3 MOSFET transistors – 1 for heated bed, 2 for hotend

  • Slot for SD card

  • Support and filtering of 3 endstops

  • 3 pins for thermistors

  • Support for SPI screens - Viki2, mini Viki and RRD Graphic LCD (via adapter)

  • Output headers for connecting an ethernet module (RJ45)

Re-Arm is a microcontroller development board designed to control 3D printers via an additional adapter board Ramps 1.4 or Ramps 1.6 . The board serves as a replacement for the commonly used 3D printer Arduino MEGA2560. It is built on the basis of the LPC1768 microcontroller, with a clock frequency of 100MHz, 512kB flash and 64kB SRAM memory. On socket headers with a 2.54mm pitch, 36 digital input/output ports and 8 analog inputs are brought out, as well as 5V, 3.3V and GND. Of the digital I/O ports, 6 can be used as PWM (pulse-width modulation). The arrangement of the socket headers corresponds to that of the Arduino MEGA2560, although some of the headers are not connected to microcontroller pins. An indicator LED is available – PWR(indicates the presence of 3.3V supply voltage). Near the DC connector is located a RESET button, used to restart the microcontroller board.

Power supply for Re-Arm is provided via the USB connector or DC connector 5.5x2.1mm. The power supply range for the DC connector is 10-30VDC.

The following additional signals are brought out on the socket headers:

• UART – TX, RX, 5V, GND
• LCD/SD/SPI – 5V, GND and respective pins from the microcontroller (visible in the Re-Arm schematic)
• LAN/GPIO – 3.3V, 5V, GND, pins for connecting Ethernet and other general-purpose pins.

• ANALOG INPUTS – additional analog inputs

Advantages of Re-Arm compared to Arduino MEGA2560 when used in a 3D printer:

• Higher movement speed – thanks to the higher clock frequency, more frequent pulses are possible for the STEP pins of the drivers
• Works with Smoothieware firmware – thanks to the 32-bit microcontroller, it is possible to use Smoothieware firmware for CNC systems including Lasers and 3D printers. Smoothieware is open source and available on GitHub
• Easy use of SD card – the memory card is visible in windows, allowing easy changing of operating settings – by uploading a new text file
• Filtered inputs for endstops

Additional information:

• Open source Smoothieware firmware website
• First steps and using the board
• Schematics and features of Re-Arm