I searching for some RPM sensors and I've bought E18-d80nk but it's range is about 7500 RPM, what should I look for?
Obs: I'm using a O.S 55 AX Engine and I'ld like to see the propelers RPM!
Normally an everyday LDR (light dependant resistor) is used.
I see no requirement for any IR device, would only be complicated by the presence of sunlight etc. anyhow.
This post recommends a phototransistor instead........
An rpm sensor outputs one or more pulses per revolution. Choose the number of pulses depending on the typical velocity you want to measure. An LDR will be too slow for such applications, use a (reflective) light barrier instead.
A QRE1113 might do the trick.
I use the QRE1113 for measuring the speed of a small DC motor. In my case it detects a blob of white paint on a black 8mm plastic disk on the motor shaft. However it is close range device (about 1mm IIRC) so may not be suitable for detecting a propeller.
There is a wide range of reflective optical detectors that come with an IR LED and a photo transistor. Have look in the online catalogues of the major component suppliers such as RS components or DigiKey.
The program that I use with my QRE1113 is in this link.
...R
This is a model aircraft engine and I imagine it will be used at time outdoors in bright sunlight.
Example of a photo transistor unit.
Note top end range.