Easily measuring inductance with Arduino « ReiBot.org. Bidirectional analog to digital - using LM741 as comparator.
So you need to make or measure an inductor, but you don’t have an oscilloscope or signal generator? Measuring inductance with a handful of cheap common parts is certainly possible. I’ve verified this method is accurate with a scope from 80uH to 30,000uH, but it should work for inductors a bit smaller or much larger. There are some contingencies to keep in mind when it comes to measuring inductors — more on this in “Other Notes:“
Breadboarding. Programmers. ARDUINO.