Everyone needs a hardness tester.

[tonyfoale]

So after a few false starts and many distractions, I finally built myself a version of Tony's Leeb hardness tester...................
.........Thanks for all the work you did on this Tony and thanks especially for the through presntation on the theory and "how to do it" info you shared.

Great to see that you found my original post useful.

You may recall that in my PDF I stated that polling gave better results than using interrupts. For projects since I made the hardness tester I have used ESP32 boards in place of Arduinos. ESP32 is like an Arduino on steroids, they are many times faster. So if I was doing this project today I would try using interrupts on an ESP32 in place of polling on a Nano.