K40 to RPI CNC adapter PCB

K40 Ribbon Cable to RPI-CNC adapter. Since the RPI-CNC has strong pull-ups on the limit switch inputs, this board uses transistors to invert and amplify the signal.

Component side

Solder side

This board also breaks out the X-axis stepper pins.

Source (KiCAD)

Order from OSH Park


  • 1 TE connectivity 1-84534-2 connector
  • 2 3K3 0805 SMD resistors
  • 2 MMBT2222A SMD transistors
  • 2 1×2 0.1″ pitch header [OPTIONAL]
  • 1 1×4 0.1″ pitch header [OPTIONAL]
  • 1 0805 SMD capacitor (noise reduction) [OPTIONAL]