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Arduino Shield for GRBL from

grblShield is a complete plug-and-play stepper driver hardware solution for grbl. It can drive any NEMA17 motor we have seen, and with cooling it will drive NEMA23 motors rated up to about 2.5 amps. It is also capable of driving a dual Y configuration using NEMA17 or NEMA23[1] motors by wiring the Y axis in parallel or serial to the motors. It's most comfortable with a power supply of 24 volts at 4.5 amps or greater.


  • Compatible with the Arduino Uno, Seeeduino, and other atmega328p Arduinos and clones
  • Compatible with grbl 0.7 and later (the current release of grbl is 0.8 as of March, 2013)
  • Three stepper motors supporting X, Y and Z axes
  • 8x microstepping
  • 2.5 amps per winding (bipolar steppers)
  • 12v-30v motor voltage supported
  • Independent current control per axis
  • Uses TI DRV8818 stepper drivers.

Note about the Z axis microstep modification

Shapeoko can run faster and more optimally if the microstep setting for Z is changed independently of X and Y. This is because X and Y are belt driven and Z is screw driven. In the v4 boards (blue boards) this is done with a jumper to set the Z axis to 2x microstepping. On the v3 and earlier boards (green boards) a simple board modification can be made to leave X and Y at their default 8x microstep values while changing Z to 2x microstepping. This mod can be requested when you purchase a grblshield, and is included in all the Inventables full-kit purchases. If you have an earlier board or are just curious, full details of the process are shown here. [2]