Counting UK Coins?

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Pure

New Member
Hi!

I am wanting to create a circuit that counts coins, outputting the amount to four 7segs.
I have the display portion firgured out, I need the input part and the logic.
Is there an easy way to count UK coins, possibly with a way to decrease the count when I want to remove the coins?

Thanks in advance!
 
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Andrew Cowan

Senior Member
Are you looking to do this with logic, or with a PICAXE (or two)?

The hard part is recognising coins. I have done this in a project before using fibre optics and laser beams, but it is a tricky task.

A
 
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manuka

Senior Member
Did someone mention money?! No doubt I'd not be the first to say "send them all to me & I'll handle everything". Yes - Maundy money,half crowns & even the odd guinea - I'll even pay the p&p & conduct a personal bite test for gold sovereigns! At the rate the £ is falling your current coins may soon be at parity with the € anyway, so make haste before things go like the $ Zim...

Seriously though,a classical issue often relates to coin wear OR dirt etc biasing what was a precise weight at minting. Naturally fakes (!) or foreign coins may be mingled in with your sterling. At first ponder I'd say both weigh AND size each coin to ease the hassles. But how much filthy lucre is involved? What error is acceptable? Why bother with the low value ones anyway ? You naturally could wave a magnet over suspect pound coins, & even clever optical techniques may now also be tempting on such distinctive ones as the 7 sided 50p coin.
The weight of currently circulating British coinage is as follows:

One pence: 3.56g
Two pence : 7.13g
Five pence : 3.25g
Ten pence : 6.50g
Twenty pence : 5.00g
Fifty pence : 8.00g
One pound : 9.50g
Two pound : 12.00g
Five pound : 28.28g
Click to expand...
That's the easy bit - in more detail you'll see thicknesses have changed, even in recent times.
1 Penny (from 1968 - 1991) 20.32 mm diameter, 1.52 mm thick, weigh 3.56 grams and are made from 97% copper, 2.5% zinc and 0.5% tin. The edge is plain.

1 Penny (from 1992) 20.32 mm diameter, 1.65 mm thick, weigh 3.56 grams and are made from copper plated steel. The edge is plain.

2 Pence (from 1971 - 1991) 25.9 mm diameter, 1.85 mm thick, weigh 7.12 grams and are made from 97% copper, 2.5% zinc and 0.5% tin. The edge is plain.

2 Pence (from 1992) 25.9 mm diameter, 2.03 mm thick, weigh 7.12 grams and are made from copper plated steel. The edge is plain.

5 Pence (from 1990) 18 mm diameter, 1.7 mm thick, weigh 3.25 grams and are made from 75% copper and 25% nickel. The edge is milled.

10 Pence (from 1992) 24.5 mm diameter, 1.85 mm thick, weigh 6.5 grams and are made from 75% copper and 25% nickel. The edge is milled.

20 Pence (from 1982) 21.4 mm diameter, 1.7 mm thick, weigh 5 grams and are made from 84% copper and 16% nickel, and are seven sided. The edge is plain.

25 Pence (from 1972 - 1981) 38.61 mm diameter, 2.5 mm thick, weigh 28.28 grams and are made from 75% copper and 25% nickel. The edge is milled. During their period of issue, they were referred to as a Crown due to them being of the same dimensions as the pre-decimal Crown coin. These coins were discontinued from 1982 but remain legal tender. Circulation of these coins is uncommon.

50 Pence (from 1997) 27.3 mm diameter, 1.78 mm thick, weigh 8 grams and are made from 75% copper and 25% nickel, and are seven sided. The edge is plain.

1 Pound (from 1983) 22.5 mm diameter, 3.15 mm thick, weigh 9.5 grams and are made from 70% copper, 24.5% zinc and 5.5% nickel. The edge is milled with incuse lettering or ornamentation.

2 Pound (from 1986 -1996) 28.4 mm diameter, 3.1 mm thick, weigh 15.98 grams and are made from 70% copper, 24.5% zinc and 5.5% nickel. The edge is milled with incuse lettering. Circulation of these coins is uncommon.

2 Pound (from 1997) 28.4 mm diameter, 2.5 mm thick, weigh 12 grams and are bimetal made from 76% copper, 20% zinc and 4% nickel in the outer ring, and the centre is 25% nickel and 75% copper. The edge is milled with incuse lettering.

5 Pound (from 1990) 38.61 mm diameter, 2.89 mm thick, weigh 28.28 grams and are made from 75% copper and 25% nickel. The edge is milled. Intended as a souvenir or collectible, but occasionally seen in circulation. These coins are now referred to as a Crown due to them being of the same dimensions as the pre-decimal Crown coin.
Click to expand...
Mmm- is it possible that you intend first manually sorting the coins into their denominations ?
 
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manuka

Senior Member
That site also has classic coin sorters. Organising such a stack may be yet another preliminary approach, as any fakes would soon show themselves when near the real ones.
 
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Haku

Senior Member
This is something I could do with that counts individual coins into the right amounts for the coin bags banks give out, my loose change 'jar' now weighs over 13.5kg... ;)

Interestingly, Tesco's self-service machines can't tell the difference between 5p and an american dime as I found out recently when checking my loose change to put in the 'jar'.
I also have a fake £2 (some foreign currency that looks almost identical at a glance) and a fake £1 (made of soft metal that scratches easily).
 
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Rickharris

Senior Member
Apparently around 1 in 5 £1 coins is a fake. Generally the head and tail are not aligned and the edge milling and writing is poorly defined. I have seen loads.
 
fernando_g

fernando_g

Senior Member
I once read that the better coin sorters, in addition to weight/size, also employ a hall-effect sensor to distinguish the coin's magnetic signature.

"At the rate the £ is falling your current coins may soon be at parity with the € anyway"
Not to forget the Greece's problems dragging the €!! Nor the huge deficit weakening the US$, which somehow maintains its value thanks to the Chinese treasury's massive purchases, to keep the Renminbi at parity.

There has been tremendous pressure to the Chinese government to stop that practice and allow the RMB to appreciate. The Chinese resist, of course, since that would increase the cost of Chinese exports.

There have been indications however, that the Chinese have finally recognized that there should be some RMB appreciation. Whether that will happen or not, that is anybody's guess.
The other day I saw a financial commentator saying that, if you are an audacious investor with a flair for heavy gambling, that you should change all of your $$, €€, ¥¥ and ££ to RMBs, and probably make a fortune.
Or maybe not.
 
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slurp

Senior Member
Rickharris said:
Apparently around 1 in 5 £1 coins is a fake. Generally the head and tail are not aligned and the edge milling and writing is poorly defined. I have seen loads.
Click to expand...
I got a bag of £2 coins from the Halifax a month or two ago, I passed it straight back as it was clear one of the coins was a dud... Out of the bag the head, tail and edge milling looked good, the problem was the gold. It was paint and flaking off.

When the rechecked weight it was a little off, I guess their bag check said it's close enough for me! :D

regards,
Colin
 
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AndyGadget

Senior Member
I cornered a DeLaRue service engineer some time ago and asked him about coin sorting.
He wasn't too sure about the exact details, but the machines he worked on used several paired transmitter / receiver coils at various frequencies which the coins dropped past. The coins could be characterised by changes in field strength.

Andy.
 
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Minifig666

Senior Member
Rather than going OTT with weight, colour, or even hall effect the easiest way to go is size. I have two solutions;
A hole with of a £1 coin with a sprung lever with a ball bearing or some other form of contact on the end which has V+ on it. Then set up a set of contacts on a PCB or something similar. Push a coin through the hole so that it goes to a particular contact. Then use a PICAXE to decode which contact a particular coin is equivalent to.
I shall add a visual version in the morning and the other idea as well.
 
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