I am trying to measure the RPM's of a fuel engine which has gears. I have received a free KMI15/1T1 sensor but when I reference the data sheet it only uses 2 pins: you have to supply 12V and depending on the rotation the current will change from 7 mA to 14 mA.
Any suggestion how I am going to measure this with the Arduino?
(eg: 15 modules / sec = 15 Hz Current from 7 mA to 14 mA back and forth)