Waag Society Fablab Amsterdam

The Mantis needs an (accurate!) endstop.

We had Hall sensors in stock, so I designed a PCB in Eagle CAD to hold a Hall sensor, an op-amp to convert the signal to an on-off signal and a potentiometer to easily adjust the threshold.

I milled it on the Modela using a toolpath generated by cad.py (1/100" milling bit, Z min -0.005, Z max 0.05, XY speed 4, Z speed 4, 3 contours)

After that, I changed to a 1/32" milling bit for drilling and milling the PCB loose (Z min -0.065, Z max 0.05, XY speed 0.5, Z speed 0.5, 1 contour)
Getting that right required some fiddling with the colours in the image with the GIMP - making the holes black, the outline black and the area within the outline white.

Parts:

• A1302KLHLT-T (Hall sensor)
• AD8605ARTZ (op-amp)
• 0.1" header 3-pin
• 10k potentiometer (any value between 1k and 100k or so is fine, as long as the pins are next to each other and fit)