ERCF Belay Filament Stress Sensor - updated with thicker walls and space for PC4 clip

BOM:

• 2x D2F-L switches
• 4x M2x10 screws (I use self-tapping to thread easily into the plastic)
• 1x PC4-M4 fitting
• 1x PC4 fitting (I think any size thread will work because the thread isn't used, but I'm using an M10 one)
• PC4 clip
• Whatever Bowden tube you are using

Happy Hare config for MBB board:

mmu_hardware.cfg:

sync_feedback_tension_pin: ^mmu:MMU_FIL_TENS
sync_feedback_compression_pin: ^mmu:MMU_FIL_COMP

mmu.cfg (add to bottom):

    MMU_FIL_TENS=PB4,
    MMU_FIL_COMP=PB3,

I ran two separate ground wires before I realized it wasn't necessary. You can simply run a jumper between the two grounds and run one ground wire to the controller.

Reoriented for printability and ease of filament feed through 
and to thicken walls and provide space for a PC4 clip