are connected straight between the limit switch pins of the board and 0V through short connections. Visual fault indication Only the six resistors and three opto-isolators on the left of the circuit ...

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 wired to the same input (hence only three ...

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 ...