It’s been over a year since I built an Arduino microcontroller at our club’s annual construction night, and I still haven’t done anything with it. I’ve had a couple of ideas, including a keyer that would actuate accept paddle inputs and actuate a solenoid that would open and close a straight key, but just haven’t had the time or inclination to actually put something together.
Well, here’s a cool idea as to how to use an Arduino to measure inductance.
A signal in from the Arduino excites an LC circuit. The L in the LC circuit is our unknown inductor. The output of the LM339 is a square wave whose frequency is proportional to the L of the LC circuit. Measure that frequency with the Arduino and you know the unknown inductance. Of course, calibrating this thing could be a bit tricky, but it might be fun to play with.