I need to build inductor 330uH for LM2575, but I can't find it in our store, and the LCR meter is expensive, so I built Arduino inductor meter.

http://reibot.org/2011/07/19/measuring-inductance/

I used it for marked inductors for testing, big size of 100uH is passed, but small 100uH (small like a resistors), or 150uH it give me wrong numbers

for example

150uH -> 180uH

100uH(small) -> 40uH

I modified the circuit to make it permanent oscillator instead of just a ring (based on page on AAC), I just added a resistor (560ohm) then I changed the code, I had removed the delay function, and measure the full wave. (random value of 560ohm )

It work with fine and all my marked inductors, it get me same numbers on the covers.

#But#

I feel there is something wrong, especially, I have wrong number every 10 numbers, it is like a heart beating, not sure if my chinese Arduino or this circuit.

Code:

```
Pulse:64.00 Frequency:15625.00Hz Inductance:100.24uH
Pulse:64.00 Frequency:15625.00Hz Inductance:100.24uH
Pulse:64.00 Frequency:15625.00Hz Inductance:100.24uH
Pulse:64.00 Frequency:15625.00Hz Inductance:100.24uH
Pulse:64.00 Frequency:15625.00Hz Inductance:100.24uH
Pulse:58.00 Frequency:17241.38Hz Inductance:82.33uH
Pulse:64.00 Frequency:15625.00Hz Inductance:100.24uH
Pulse:64.00 Frequency:15625.00Hz Inductance:100.24uH
Pulse:64.00 Frequency:15625.00Hz Inductance:100.24uH
```

I published it on github

Thank you in advance.