Use Instructions and Software Upgrade

Connect directly to the arduino using the Arduino USB serial driver included with the Arduino toolkit, and then use a GcodeSender, such as the universal GCode sender.

The older Windows based gcodesender had a write speed override, but only worked at 9600 baud.

Or Connect via Grblweb and a raspberry pi.


Grbl Control Codes

Grbl compiled to start in alarm mode, you must do homing cycle to unlock the CNC.

$ - check information

$$ - check configuration settings

$H - homing cycle

$X - unlock from alarm

#define CMD_STATUS_REPORT '?' #define CMD_FEED_HOLD '!' #define CMD_CYCLE_START '~' #define CMD_RESET 0x18 // ctrl-x. #define CMD_SAFETY_DOOR '@'

Reset Zero (going to recompile GRBL to have this automate after a homing cycle)

G10 P0 X0 Y0 Z0

(this changed in different Grbl versions)

GRBL compile settings

Set compiler to set zero after homing:

You will need to uncomment the #define HOMING_FORCE_SET_ORIGIN in config.h, re-compile, and re-flash. That's it!

in Grbl 0.9, the serial speed is 115200, I set it back down to 9600, to be compatible with older Gcode sending programs:

// Serial baud rate
#define BAUD_RATE 9600

Use homing in two Axis:

change the homing cycle configuration in the config.h file

  • The first line must be : #define HOMING_SEARCH_CYCLE_0 ((1<<X_AXIS)|(1<<Y_AXIS))

  • Remove or comment out the line with HOMING_SEARCH_CYCLE_1.

  • Also, the last line must be: #define HOMING_LOCATE_CYCLE ((1<<X_AXIS)|(1<<Y_AXIS))

GRBL .9 changed P11 to spindle from limit for PWM, Disable VARIABLE SPINDLE to use old pinout.

// #define VARIABLE_SPINDLE // Default enabled. Comment to disable.


Wired interface raspberrypi DHCP B8:27:EB:3B:5B:D1

user: pi

pass: raspbian

enable wifi:
You can also connect the device to a WiFi network by first connecting via ethernet and ssh'ing to the device then editing /etc/network/interfaces

edit /etc/network/interfaces
iface wlan0 inet dhcp
        wpa-ssid "SSID Name here"
        wpa-psk "Wifi Password Here"

grblweb-wifi DHCP 74:DA:38:02:24:70

Attached below is LaserEngraver plugin updated to work with Inkscape 0.91.  The plugin is an updated version of the one linked on the software page.

Tim Hettinger,
Jun 7, 2015, 5:30 PM
Tim Hettinger,
Jun 7, 2015, 5:32 PM
Tim Hettinger,
Jun 10, 2015, 1:35 PM