Tachometer for engine test bench -Reports

Tachometer for engine test bench


Sensor	TachoBoard

I bought a photoreflector for $1. Photoreflector is photo sensor with light source. Its catalog data shows good performance. The response time is 10us. However the example of the reflector object is white paper of which reflection ratio is 90%, and the distance is 6 mm only. I tried a gray prop of APC. The result is not good at all. Polished SUS is very good result. On testing, I found ambient light is useful for detecting the gray blade. I got the distance about 1" with a comparator of setting threshold on/off output level. I worked it as a tachometer for my engine test bench. I show another photo with a angled plate. The photoreflector type is RPR-220 made by Rohm.