Dear Arduino users, any of you out there that could answer some of my questions ?
My goal: to measure RPM of our ships diesel engine. Hardware: arduino mega 2560 + ethernet shield, inductive sensor (pepperl+fuchs, datasheet here: http://www.pepperl-fuchs.com/global/en/classid_143.htm?view=productdetails&prodid=296
The engine can make 650rpm max but the sensor detects 4 holes in our huge flywheel so that generates a pulsetrain of max 44Hz.
I found lots of code for rpm calculations but I am at lost on how to connect the sensor to the Arduino for it puts out 24V.
I suspect that a voltage regulator (L7805ac-v) can not dissipate the voltage overshoot fast enough to keep up with the pulsetrain, maybe the same goes for a "ruggeduino" (tolerates 24V on its pins), not sure tough.
Any suggestions ? Optocoupler ? Transistor ?