The ever-growing family of stepper motor drivers and driver shields from Amber Spyglass Ltd has one member.
GAUPS, or GRBL Arduino Uno-compatible Pololu driver Shield, is our response grblShield and the Buildlog.net Arduino-compatible stepper driver shield. Like the Buildlog.net shield, and unlike the grblShield, it does not have built-in drivers. It accepts up to four Pololu, StepStick or compatible driver carrier boards. GRBL directly supports only three drivers, but jumpers can configure the fourth driver as a second Y axis driver. That feature is very handy for a dual-Y drive Shapeoko or eShapeoko (dual-motor upgrade).
GAUPS supports all versions of the Pololu DRV8825 (purple) driver; the Buildlog.net shield needs a small modification for the early version (rev A).
GAUPS is very similar, but not identical, to the Buildlog.net shield. While the schematic has only small differences (given GRBL on the Uno and four Pololu drivers, there aren't many ways to connect them that make sense) and the layout is almost the same, the board is redesigned from the ground up. It has fatter VMOT traces, and a better connected ground plane. It uses DIP switches to set microstepping, instead of jumpers.
GAUPS is derived from Bart Dring's open-source buildlog.net Arduino-compatible Stepper Motor Driver Shield rev 3. Thank you, Bart!
GAUPS is open-source hardware, released under the Creative Commons Attribution-ShareAlike 3.0 License. KiCAD files will be available here soon.
This is the beta version of the board. It works perfectly, but the layout isn't quite perfect. The final version will have + and − swapped on the power connector, larger pads and vias, slightly fatter traces, and an even better ground plane. Version 0.2 uses DIP switches to select the function of the fourth driver; version 1.0 uses jumpers, and version 1.1 solder bridges (but both retain the DIP switches for microstepping).
Click for GAUPS 0.2 Instructions.
This is the previous production version of the board.
Click for GAUPS 1.0 Instructions.
This is the current production version of the board.
Click for GAUPS 1.1 Instructions.