It’s built in the typical CoreXY fashion, running GRBL firmware on an Arduino Uno ... [TUENHIDIY] notes the importance of limit switches in the design. These allow the the ‘bot to make ...

This is even an official GitHub/gnea/grbl isolation circuit for folk to add to typical commercial grbl boards With grbl, both limit switches for any axis are ... for more than a year ond only requires ...

The DIL header on the right breaks out all of the connections to the limiting switches (two for each axis), spindle and coolant control, as well as three buttons for pause, resume, and abort.