Introducing GRBLDuino Mega Integrated

The latest project is integrating a GRBLDuino Mega Shield with an Arduino Mega – no more shield! The entire system is now contained in one easy to use board: the GRBLDuino Mega Integrated.

It has all of the same features as the GRBLDuino Mega Shield:


  • Smaller than an Arduino Mega – 3.5″ x 2.3″ (89 x 58 cm).
  • CP2102 USB to UART interface – shows up as a serial port and works with Arduino IDE
  • On board reset button.
  • Designed for Pololu DRV8825 stepper motor drivers and are compatible with all pin-compatible equivalents.
  • Maximum input voltage of 45 volts DC
  • Jumper selectable high/low limit switch activation.
  • RC filters on limit switch and probe inputs.
  • All machine connections are broken out to screw terminals.
    • + and – Limit switches for each X, Y, and Z axis.
    • Resume, Hold, Abort, Emergency Stop, Door Safety support.
    • Flood and Mist coolant connections.
    • Spindle Enabled, Direction, and Speed (PWM) connections.
    • Probe connection.


The schematic is pretty straightforward – it shows all of the internal connections on the board and external connectors.

Bill of Materials

  • 1x GRBLDuino Mega Integrated PCB
  • 1x ATMega2560
  • 1x CP2102
  • 1x 16MHz crystal
  • 1x micro B USB jack
  • 18x Two position screw terminal blocks
  • 6x 1×8 female pin headers
  • 1x 1×3 male pin headers
  • 3x 1×4 male pin headers
  • 4x 2×3 male pin headers
  • 1x 6mm tactile switch
  • 1x 680 ohm resistor network
  • 5x 10k ohm resistors
  • 1x 1k ohm resistor
  • 3x 100uF, 50v Nichicon capacitors
  • 3x 22pF capacitors
  • 4x 0.15uF capacitors
  • 6x 0.1uF capacitors
  • 1x 1uF capacitor
  • 1x green LED
  • 9x short 2 pin jumper shunts
  • 1x long 2 pin jumper shunts

Gerber Files

For those wishing to make their own board, the Gerber files are provided. There are no guarantees made to accuracy or completeness of these files.


I anticipate these being available for sale through a few outlets beginning in early June. Kits will sell for around $36 shipped in the US and assembled boards will sell for around $61 shipped in the US. Once available, the best price will be at the Eccentric Workshop store, but they will also be on Tindie and eBay.

Future Versions

Version 2 will likely add in relay drivers on the coolant and spindle enable lines to control external devices. If there is enough demand, I would explore creating a 6 axis version also.