Coin sensor

[Harry Pfeifer]

I am working on a microcontroller based project, which is to be coin
operated, but do not yet have a working coin collection system.

I have a quantity of devices described as "coin sensors" which came as
freebies along with some other wanted components which I bought some time
ago. They consist of three flat coils mounted side by side, with two slots
in between, where coins could be passed through. The two outside coils are
wired in series, but the centre coil is a separate circuit. I tried
connecting one coil circuit to a signal generator and the other to a CRO to
see what response they gave when a coin was passed through them. There was a
response, but it was not consistent, and did not adequately distinguish
between coins of different values, or steel washers, whereas the
commercially available coin receivers costing several hundred dollars, and
which appear to operate on a similar principle,are able to distinguish
between coins of different values

Could someone please give me information on how they achieve this, or
alternatively, how the coin sensors which I have, are intended to be
connected.

Harry

 

[The Real Andy]

n Sat, 14 Oct 2006 00:52:45 GMT, "Harry Pfeifer"

I am working on a microcontroller based project, which is to be coin
operated, but do not yet have a working coin collection system.

I have a quantity of devices described as "coin sensors" which came as
freebies along with some other wanted components which I bought some time
ago. They consist of three flat coils mounted side by side, with two slots
in between, where coins could be passed through. The two outside coils are
wired in series, but the centre coil is a separate circuit. I tried
connecting one coil circuit to a signal generator and the other to a CRO to
see what response they gave when a coin was passed through them. There was a
response, but it was not consistent, and did not adequately distinguish
between coins of different values, or steel washers, whereas the
commercially available coin receivers costing several hundred dollars, and
which appear to operate on a similar principle,are able to distinguish
between coins of different values

Could someone please give me information on how they achieve this, or
alternatively, how the coin sensors which I have, are intended to be
connected.

Harry

Can you take a photo of it and post it to a website somewhere?
Typically there are 2 main types of coin validators. One is an
electronic unit that measures metallic content and then either sets an
output high or sends a serial message. These can be single
denomination or multi denomination. The latter being far larger in
size.

The other type is a single denom coin comparator. These measure the
metallic content of a reference coin then compare it to the coin
traveling through the slot. They are typically analogue devices that
from memory run from 24VAC. Most will divert the coin to another chute
if it does not match, with the actual coin count being handled by a
photointeruptor. In fact, there is usually 2 sets of optics that can
also detect coins going in the wrong direction in case some is trying
the ol coin 'YO-YO'!

 

[Mark Harriss]

Old Telstra yellow payphones used weight to accurately detect coins,
this was good enough to determine if a coin was Australian or Kiwi
as the identical sized Kiwi coins were of a different weight but
identical size and most likely to end up in a coin slot. I forget
if they had different diameter chutes for the coins to be sized in
before weighing but they passed extensive testing using slugs, washers
etc.

 

[jasen]

n Sat, 14 Oct 2006 00:52:45 GMT, "Harry Pfeifer"

easiest way is to buy one, Microsystems Corp. makes a good product.

The other type is a single denom coin comparator. These measure the
metallic content of a reference coin then compare it to the coin
traveling through the slot. They are typically analogue devices that
from memory run from 24VAC. Most will divert the coin to another chute
if it does not match, with the actual coin count being handled by a
photointeruptor. In fact, there is usually 2 sets of optics that can

it sounds like he could place a good coin in one of the slots and then
feed one of the coils with a reference signal [maybe a 1Khz square wave?]
and look for a null on the other coil when another coin of the same type
passes through the other gate,



Bye.
Jasen

 

[The Real Andy]

easiest way is to buy one, Microsystems Corp. makes a good product.

True this is, but did the OP not ask about an existing unit?

The other type is a single denom coin comparator. These measure the
metallic content of a reference coin then compare it to the coin
traveling through the slot. They are typically analogue devices that
from memory run from 24VAC. Most will divert the coin to another chute
if it does not match, with the actual coin count being handled by a
photointeruptor. In fact, there is usually 2 sets of optics that can

it sounds like he could place a good coin in one of the slots and then
feed one of the coils with a reference signal [maybe a 1Khz square wave?]
and look for a null on the other coil when another coin of the same type
passes through the other gate,

You have no idea, perhaps its time you stopped pretending to be a
genius by reading the internet and focused on shit you actually know
something about.

 

[R1rob]

Ebay. Pinball machine section. Can usually be had cheap.

Rob