Upgrade Your CNC : 8 Steps (with Pictures) - Instructables
To do this, connect your CNC to a PC with a USB cable. Use the Arduino IDE (or any other terminal) to connect to the CNC by opening a new serial monitor (make sure you select the correct baud rate). Type $$ to view the current settings. Type $22=1 to enable homing. Type $27=5 to adjust the homing pull off.