On 2017-05-25, Larry Jaques wrote:
On Wed, 24 May 2017 08:29:44 -0700, pyotr filipivich
wrote:

[ ... ]

Harbor freight has a coin sorter for sale. Battery operated/.

https://www.harborfreight.com/money-...ter-98052.html

I'll have to grab one of those. Coin rolls are much easier to sling
around than coffee cans, I'll bet. I'd also like to find an aluminum
magnet which could separate the aluminum pennies from the solid
coppers.

actually -- this is possible, except that the pennies are zinc
inside the copper skin, not aluminum.

Set up a ramp with a groove that the pennies can roll down.

Just as they exit, run them through a voice-coil magnet assembly
from an old (not too old, but non-functional) disk drive. Set this on
the edge of a table, and first roll known copper pennies through it and
note there they hit the floor. Then do the same with the zinc-copper
pennies. They will land in a different area. The moving penny
generated an indictively generated magnetic field in the pennies, which
slows them down -- differently depending on the mass and the
conductivity. Copper is a much better conductor than zinc is, so the
copper pennies will be slowed down more. The higher the starting point
of the ramp, the greater the speed, and the greater the difference in
speed after they go through the magnet assembly.

Enjoy,
DoN.

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