Shaft

I decided to build an IR based RPM sensor. I primed and painted the motor shaft. I used some old Krylon camouflage brown paint. (I was out of black.) The camouflage paint is ultra-flat. So, this should absorb most of the IR energy.

I painted opposite sides of the shaft with white high gloss paint which will reflect the IR energy. The radio of reflective to flat is 1:2. I could update the paint to emulate other pulse ratios.

The upper and left mounting holes will support the mounting bracket.