Right-angle holder or bracket for Optek OPB917 opto-interruptor sensor. Sensor center is held about 44 mm above surface. Sensor mounts to bracket with 2x M3 or 4-40 screws, bracket mounts to surface with M4 or similar screw. Two versions provided: with a closed mounting hole, and also a slot which makes it easier to install and remove.OpenSCAD file included for customization. This was designed for use with this motor/pulley/slotted wheel assembly: https://youmagine.com/designs/pulley-slotted-wheel-for-4rpm-gearmotor