Converting the Duplicator I3 Melzi controller board to a RADDS controller

This modification applies to all versions of the Duplicator i3 and is for the serious modder and tinkerer. Performing this mod will most likely void your warranty.  Proceed at your own risk.


This guide will help explain the steps required to convert from using the Melzi controller board to a 32bit processor RADDS board. More information on the RADDS board can be found on the RADDS Electronics for 3D Printer.


  • 6 Steppers on-board : X,Y,Z, E0, E1, E2. (Sample: 3 axis and 3 extruders (Z-axis, and E3 extruder, comes with 2 pins strips for optional second stepper).
  • 6 Heavy duty MOSFET`s (Sample: 1 HeatBed, 3 HotEnds and 2 fans)
  • SD-Card (micro-SD-slot onboard, optional external SD-slot)
  • Standard LCD (5V) with 4×20 characters (HD44780 compatible)
  • Rotating encoder (on LCD panel)
  • 6 endstops (Xmin,Ymin,Zmin,Xmax,Ymax;Zmax)
  • 5 thermistors and an ADC
  • 3 servomotors
  • I2C, SPI, CAN, DAC, RS232 and 8 digital-pins available via pin strips
  • Control-LEDs for loads and operation voltage
  • Catch-diodes on the MOSFET`s
  • Car-fuses instead of thermo fuses
  • Variable input voltage: can be supplied from 10V up to 25V
  • Heatbed electronic control supports up to15A without a heatsink
  • Premium screw terminals

– See more at:


The Repetier firmware (0.92.3) configured for the RADDS board with the RADDS LCD can be downloaded from Dropbox Link
You will need a newer installation of the Arduino IDE (1.6.x) and have the SAMX board support installed. Select the DUE board as the board type before compiling.


I designed a mounting plate for the original Wanhao I3 and a faceplate to replace the LCD with a USB connector on Thingiverse

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