Look Mummy no Puppets, I do useful things with my 3D printer Now.
stl file = hall_effect_sensor_ic_housing.stl
solder 3 wires to hall ic and fill with hot glue
put hall ic right side between little gap in bottom
After some searching the Hall Effect IC i chose / decided to use
is Hall Effect IC A3144 is 4mm wide 1.5mm thick 3mm high A3144 Unipolar Non-latching
North Pole sensitive about 2cm with neodymium magnet
drain, sinks, pulls to ground when correct N pole side magnet present