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Science Forum Index » Physics - Electromagnetic Forum » Coins - Magnetic properties
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| Skyme |
 Posted: Tue Feb 12, 2008 4:44 am |
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Guest
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Hello:
I found this group on the internet by chance and thank goodness I did,
what a wealth of useful information.
I am currently researching a coin detection circuit and have been
advised to investigate this idea using the weight, and size of a coin,
and by utilising the magnetic properties of coins. Having very little
knowledge of magnetic circuits and theory I am politely enquiring if
their are any simple ideas/circuit which would be able to detect
variations in a certain property of different coins.
My initial thoughts were to input a sine wave into a magnetic coil and
measure some given property change although sue to my weak knowledge I
do not know what this would be.
Any thoughts would be deeply appreciated.
Thank You. |
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| Benj |
| Posted: Tue Feb 12, 2008 6:23 am |
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On Feb 12, 9:44 am, Skyme <skyman...@gmail.com> wrote:
Quote: Hello:
Any thoughts would be deeply appreciated.
Thank You.
Coin boxes on vending machines are highly developed and I'd suggest
searching there. I'm no expert on that but if I recall correctly they
work by coin size and electrical (magnetic) properties. I think they
actually bounce the coins off of something as well to measure weight.
The key magnetic property as I understand it is to pass the coins by a
magnet so that the motion creates eddy currents in the coin. The
"modern" sandwich coins were developed such that the layers of metals
would react to the magnets the same as the silver coins. The eddy
currents create a braking action on the traveling coin that can direct
it into valid and invalid pathways.
Perhaps someone who knows more about vending machine coin boxes can
tell you more. |
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| Guest |
| Posted: Tue Feb 12, 2008 1:25 pm |
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Benj <bjacoby@iwaynet.net> wrote:
Quote: On Feb 12, 9:44 am, Skyme <skyman...@gmail.com> wrote:
Hello:
Any thoughts would be deeply appreciated.
Thank You.
Coin boxes on vending machines are highly developed and I'd suggest
searching there. I'm no expert on that but if I recall correctly they
work by coin size and electrical (magnetic) properties. I think they
actually bounce the coins off of something as well to measure weight.
The key magnetic property as I understand it is to pass the coins by a
magnet so that the motion creates eddy currents in the coin. The
"modern" sandwich coins were developed such that the layers of metals
would react to the magnets the same as the silver coins. The eddy
currents create a braking action on the traveling coin that can direct
it into valid and invalid pathways.
Perhaps someone who knows more about vending machine coin boxes can
tell you more.
You've basically got it.
The coins follow a path that is determined by their size, weight, and
magnetic makeup into either an accept or reject chute.
Since duplicating all those attributes would cost more than the coins
value, there is no incentive to do much more.
When I was a kid all you needed was something the close to right size
and the material didn't matter; not anymore.
--
Jim Pennino
Remove .spam.sux to reply. |
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