I am back on the idea of an electronic way to differentiate copper pennies from zinc pennies with a copper plating. Hey, I know it's a waste of time, but I am intrigued by it.
My basic scheme is to position some strong magnets on one side of a non-ferrous channel and a coil on the other, and cause the pennies to move between the magnets and the coil so as to generate a voltage in the coil. Today, I messed around with rare earth magnets stacked up on my desk, and placed a penny on top of the stack. Then, I took a 25 foot spool of 22 AWG wire and connected the ends to my DVM. Then, I moved the spool across the top of the penny as quickly and as closely as I could.
I saw a voltage on the order of a few millivolts, but I couldn't really concentrate on the DVM while I was waving the coil. I tried it with a copper penny, a zinc penny, and without a penny and saw a voltage in all three cases, but of course I had no way to say which produced the higher voltage.
If I could determine that there was a repeatable difference in the induced voltage using a copper penny versus a zinc penny, I would be on my way.
What say the brain trust here? Am I "penny wise and pound foolish," or does this idea have some merit? What would be the optimum configuration for my coil?
Thanks.
My basic scheme is to position some strong magnets on one side of a non-ferrous channel and a coil on the other, and cause the pennies to move between the magnets and the coil so as to generate a voltage in the coil. Today, I messed around with rare earth magnets stacked up on my desk, and placed a penny on top of the stack. Then, I took a 25 foot spool of 22 AWG wire and connected the ends to my DVM. Then, I moved the spool across the top of the penny as quickly and as closely as I could.
I saw a voltage on the order of a few millivolts, but I couldn't really concentrate on the DVM while I was waving the coil. I tried it with a copper penny, a zinc penny, and without a penny and saw a voltage in all three cases, but of course I had no way to say which produced the higher voltage.
If I could determine that there was a repeatable difference in the induced voltage using a copper penny versus a zinc penny, I would be on my way.
What say the brain trust here? Am I "penny wise and pound foolish," or does this idea have some merit? What would be the optimum configuration for my coil?
Thanks.