A simple way to use the grbl-Mega software with a Mostly Printed CNC (MPCNC). The dual motors on X and Y need to spin in opposite directions. Rather than hack up the grbl software to allow E0 and E1 to be used as secondary X and Y axes on a RAMPS, this board can be plugged into the X and Y positions along with a pair of drivers.
R1 = 1k. R2 =10k. Q1 = MMBT3904. For each board you need two eight-pin Arduino shield style headers (male and female together). Two eight-pin female headers for your 2nd stepper driver, and a pair of four-pin headers to connect your motors to.