Optical Mice Used To Detect Counterfeit Coins

JimXugle writes "El Mundo reports that Spanish researchers at The University of Lleida have used a modified optical mouse to detect counterfeit €2 coins (Original article, in Spanish) with a success rate comparable to that of an expert trained to do so. Details are to be published freely in the journal Sensors."

Comments

Genius you see...

[Monkeedude1212]

The laser from the mouse will heat up the chocolate inside of counterfeit coins, thus exposing the fakes and creating a mess.

Re:Genius you see...

[Ukab the Great]

And that's why Spain will never get to host the world Dreidel championships.

Re:Genius you see...

[swanzilla]

Optical mouse LED != laser...that was pretty damn funny, regardless

Re:Genius you see...

[Anonymous Coward]

My mouse has a laser diode.

Newer Mac mice are cybernetic, touch sensitive because it has a real piece of scrotum skin stretched over the surface.

Re:Genius you see...

[hoytak]

I read your comment and laughed hard enough to sneeze snot all over my lunch. Now I'm going to go get some chocolate to make it okay. Fortunately, it's not counterfeit.

Re:Genius you see...

[belmolis]

Not to mention the fact that they expelled us Jews in 1492...

Re:Genius you see...

[zoney_ie]

A real mouse works for that too - they'll happily gnaw through the metallic shell to get at the tasty chocolate inside.

Re:Genius you see...

[nospam007]

Newer Mac mice are cybernetic, touch sensitive because it has a real piece of scrotum skin stretched over the surface.

Mmmm, my mouse has only one ball.

Re:Genius you see...

[Anonymous Coward]

Your mouse is hitler!

Re:Genius you see...

[RockDoctor]

Mmmm, my mouse has only one ball.

I call Godwin!

- Hitler has only got one ball ;
Goering has two, but very small.

- Your mouse has only one ball.

- Therefore, your mouse is Hitler, and you've been a Hitler-massaging Nazi Party member for a significant time.

- Q.E.D. Civilised argument is over and we can get down to the rioting. Pass me the Molotov Cocktail.

No, you fool, the unlit one.

Who counterfiets 2-Euro coins anyways?

[davidwr]

Geesh, can you get me a mouse that detects North Korean bogus US$100 bills?

Re:Who counterfiets 2-Euro coins anyways?

[von_rick]

I can get you a mouse, but you will need to write the algorithm yourself.

Re:Who counterfiets 2-Euro coins anyways?

[cupantae]

Hey, it costs me only €1.80 to produce each one. You realise there's a recession going on, right?

Re:Who counterfiets 2-Euro coins anyways?

[Anonymous Coward]

The exchange rate isn't far from 1,8€ for a real 100$ bill from any bank ;)

Re:Who counterfiets 2-Euro coins anyways?

[funkatron]

Does it matter? As long as no one else can detect them they're effectively good money.

Re:Who counterfiets 2-Euro coins anyways?

[NeoStrider_BZK]

[cruel]
Im sure they have plenty of mice running around in there...
[/cruel]

[serious] ...those poor people...they deserve something better....
[/serious]

Re:Who counterfiets 2-Euro coins anyways?

[turtleshadow]

Printing money is Mafia

Minting coins _and_ printing money is Maciavellian.

Just how much Gold and Silver is inside the gravity well of earth?

I think the economists/bankers/politcos are hiding something that makes a big crashing noise in the Dark.

Re:Who counterfiets 2-Euro coins anyways?

[xaxa]

I don't know about €2 coins, but loads of £1 coins are counterfeit -- perhaps 5%. The €2 (and 1) are bi-metallic though, so presumably harder to fake.

Under UK law (as that page explains), once you know a coin is counterfeit it's illegal to give it to anyone (except the police) or to keep it. Daft, but it means it's in my interest not to identify counterfeits. (Unless, possibly, I checked every time I was given change. But that's not realistic.)

Re:Who counterfiets 2-Euro coins anyways?

[Darkness404]

Why would you want to detect counterfeit coins/bills anyways? So long as the next person takes them it doesn't really matter. Yes, if we get trillions of counterfeit notes and coins it might start being a problem, but if I can exchange a fake $100 bill for $100 worth in merchandise, it isn't to my advantage to even care if they are real or not. The problem is if you are conned by an obvious fake that the next person won't take, thus leaving you short how much cash you accepted in counterfeit money.

Re:Who counterfiets 2-Euro coins anyways?

[Anonymous Coward]

Who counterfiets 2-Euro coins anyways?

I believe your own question answers itself:
1. You believe that is not worth to counterfeit a coin.
2. You don't care about small valued counterfeited coins.
3. ... 4. I can easily put more in the market. (Profit!)

Or something like it.

Re:Who counterfiets 2-Euro coins anyways?

[nulldaemon]

...because every time I accept a counterfeit coin it's comparable to being raped.

Re:Who counterfiets 2-Euro coins anyways?

[Anonymous Coward]

£2 not that hard, I had one last week the fakes are not really bi metallic just have a coloured coating that makes them look bi metallic, and are made of some soft metal - quite easy to detect without an optical mouse.
I tried to get rid of it in a vending machine, it would not take it so I left it as part of a tip in a restaurant

Re:Who counterfiets 2-Euro coins anyways?

[c6gunner]

It's called an "analogy", dimwit. I know that slashdot users aren't exactly renowned for their intellect, but this is just getting silly.

Re:Who counterfiets 2-Euro coins anyways?

[QuoteMstr]

I tried to get rid of it in a vending machine, it would not take it so I left it as part of a tip in a restaurant

Gresham's Law in action!

Re:Who counterfiets 2-Euro coins anyways?

[Thiez]

It's a retarded analogy. With counterfeit coins, the person who finds out a coin is fake gets hurt in his/her wallot for 2 euros, and the person who made the coin gains some amount of money less than 2 euros (because making the coin wasn't free), and all the other people who owned the fake coin are unaffected. So counterfeit coins are more like inefficient pickpocketing-by-proxy than an infinite rape.

Re:Who counterfiets 2-Euro coins anyways?

[c6gunner]

With counterfeit coins, the person who finds out a coin is fake gets hurt in his/her wallot for 2 euros, and the person who made the coin gains some amount of money less than 2 euros (because making the coin wasn't free), and all the other people who owned the fake coin are unaffected.

And with rape, the person who gets raped has a shitty time for 2 minutes, and the person doing the raping has a good time for 2 minutes, and all the other people are unaffected.

If something is wrong, it's wrong regardless of how many people it hurts or how much harm it causes. We can weigh the punishment of perpetrators based on those factors, but they don't make the act any more or any less wrong.

It's a retarded analogy.

You haven't made a case to justify that premise.

Re:Who counterfiets 2-Euro coins anyways?

[Anonymous Coward]

And with rape, the person who gets raped has a shitty time for 2 minutes, and the person doing the raping has a good time for 2 minutes, and all the other people are unaffected.

You really are an idiot. Before you Google phrases like "coping with rape", and "rape survivor", take some time to think about the effect it would have on you if someone close to you was raped (think your sister or mother). Basically you're a disgusting human being for thinking that other people are unaffected, or that the "shitty time" only lasts for 2 minutes. Not the least because if you think the severity of rape is so low, one must wonder at your own propensity to become a rapist.

How does it compare to a vending machine?

[istartedi]

In what ways does it defer, if any, from the techniques used in vending machines?

If it's better, patent and sell to vending companies? Yeah... patents are evil; but maybe a novel application of an existing technology isn't so evil in this case--provided it really is novel and not just a poor-man's vending machine detector, in which case the vending machine companies may already have a patent on it...

Re:How does it compare to a vending machine?

[von_rick]

The corollary to this mouse-hack is that you can use your mouse as a scanner and coupled with an OCR program, use it for getting scribbled notes uploaded to your computer.

Re:How does it compare to a vending machine?

[shankarunni]

Vending machines rely on mechanical factors, mostly: Weight, size, metallic composition (measured by conductivity characteristics).

This one seems to focus on the graphics on the faces. It's complementary.

Re:How does it compare to a vending machine?

[Ibiwan]

I've got a great algorithm for scanning notes with the sensor from an optical mouse; the only thing I can't figure out is how to make sure the mouse knows where it is on the paper...

Re:How does it compare to a vending machine?

[BKX]

Vending machine detectors are usually just magnets (at least in the US). Very few countries make their coins with enough iron, nickel, or cobalt to be magnetic, so a magnet can pick out most slugs (the usual form of counterfeiting used on vending machines). I know; I own vending machines.

Also, it's OT, but your sig annoys the crap out of me. I use whom correctly all the time, "intensive purposes" is retarded. Begging the question, though, seems to have actually changed meanings over the years, so, being a descriptivist, I'll give you that one.

Re:How does it compare to a vending machine?

[mea37]

"It's complementary"

'What a lovely counterfeit'?

Re:How does it compare to a vending machine?

[Anonymous Coward]

In what ways does it defer, if any, from the techniques used in vending machines?

It doesn't defer anything. It does, however, differ from the techniques used in vending machines.

Someday it may also deter counterfeiters.

Re:How does it compare to a vending machine?

[Pahroza]

compliment != complement

Re:How does it compare to a vending machine?

[uglyMood]

Complement: to make complete.

Compliment: to tell a falsehood.

Re:How does it compare to a vending machine?

[Anonymous Coward]

I have sigs turned off, so I can't see what GPP says, but I think you're missing the point when you say that "begging the question seems to have actually changed meanings". The technical term about which the prescriptivists bang on is an intransitive usage. The usage which upsets them is a transitive one, so there's no particular reason for it to have a related meaning. In fact, its meaning isn't far off the meaning when taken as individual words rather than a set phrase. It's a synonym of "demanding the question", "asking for the question", "crying out for the question".

Re:How does it compare to a vending machine?

[PitaBred]

I suppose you're expecting the parent to defer to your expertise, right?

Re:How does it compare to a vending machine?

[quercus.aeternam]

I don't know where you learned the meaning of compliment, but I am in awe.

Re:How does it compare to a vending machine?

[Drishmung]

Are they just magnets?

My understanding was that the coin falls into a balanced cradle that measures the diameter and weight. If it's the wrong size it is rejected (and can fall through to another cradle that tests for a different value coin---and so on). If it is the right size but the wrong weight the cradle tips too far or not far enough and deposits it in the reject slot.

If it's the right size and weight then the coin drops between two magnets onto a little anvil. If the metallic composition is right the coin will slow just enough passing through the magnets to hit the anvil at the right place and speed to bounce into the accept slot. Anything else and it misses.

The end result is a very quick, accurate but cheap analysis of the coin's weight, size and metallic composition.

I know that's the way it used to work. Have they dumbed down the machines recently?

Re:How does it compare to a vending machine?

[uglyMood]

Stop lying.

Re:How does it compare to a vending machine?

[DeadCatX2]

If you're going to go grammar nazi on him you should have picked "defer" instead.

Re:How does it compare to a vending machine?

[emjay88]

The way they do it at Paper IQ is by having an IR ink printed pattern on the paper, which the pen (mouse in your case) can pick up.

Re:How does it compare to a vending machine?

[RiotingPacifist]

Patents are good, software patents are evil (and invalid in the EU)! This is mostly software so they can bottle up the code and sell it, but if the hardware is interesting enough (it;s not really using a standard mouse), they could patent that.

Re:How does it compare to a vending machine?

[blackraven14250]

Use motors and a microprocessor to move it instead of your hand, and an algorithm to detect the edge of the page.

Re:How does it compare to a vending machine?

[blackraven14250]

For all intents and purposes, I consider your signature invalid.

Re:How does it compare to a vending machine?

[pz]

Vending machines rely on mechanical factors, mostly: Weight, size, metallic composition (measured by conductivity characteristics).

This one seems to focus on the graphics on the faces. It's complementary.

And magnetic, don't forget magnetic characteristics. Also for size, don't forget to separately include thickness, diameter, and shape.

Re:How does it compare to a vending machine?

[mypalmike]

It's not "for all intensive purposes". It's "for all ant, ents, and porpoises." Get it right next time, OK?

Re:How does it compare to a vending machine?

[Anonymous Coward]

In fact, its meaning isn't far off the meaning when taken as individual words rather than a set phrase. It's a synonym of "demanding the question", "asking for the question", "crying out for the question".

That is precisely the change in meaning to which the OP was referring. In proper use, "begging the question" is NOT synonymous with "demanding the question". Begging the question is a logical fallacy in which the proposition to be proved is assumed in the premise. Proper use of the term might be more clearly stated as "avoiding the question". "I know he's mad because he looks really angry," is a very simple example of begging the question. The proof ("he looks really angry") is simply a restatement of the premise ("he's mad").

Sadly, these days improper usage of the phrase far outnumbers proper usage, so, in effect, the meaning of "begs the question" has changed from a logical fallacy to "raises the question".

Re:How does it compare to a vending machine?

[xaxa]

Vending machine detectors are usually just magnets (at least in the US). Very few countries make their coins with enough iron, nickel, or cobalt to be magnetic

Now all the British machines that don't accept 1p or 2p coins make sense! Thanks. (These coins are copper plated steel.)

the usual form of counterfeiting used on vending machines

Before the introduction of the Euro replaced 16 different sets of coins with one, a popular method in Europe was to put a low value foreign coins in a machine that recognised it as a higher value. IIRC old British 5p coins would be recognised in Germany as 1DM.

Re:How does it compare to a vending machine?

[Anonymous Coward]

Use motors and a microprocessor to move it instead of your hand, and an algorithm to detect the edge of the page.

Congratulations, you've just invented the scanner.

Why wasn't the above marked "funny"?

Re:How does it compare to a vending machine?

[Nefarious Wheel]

Also, it's OT, but your sig annoys the crap out of me. I use whom correctly all the time, "intensive purposes" is retarded. Begging the question, though,

A successful sig, I believe. You do know it was a deliberate troll, don't you? Or perhaps just a gentle stir (don't mod him down for that folks, it's humour). People who can't recognise the humour of deliberate mistakes have never read a book to a child (oh, the glee with which they correct you!) and that's a situation for whomever up with which I can certainly put.

Re:How does it compare to a vending machine?

[Valdez]

For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares?"

"intensive purposes" is retarded

Perhaps the poster was going for "for all intents and purposes"?

If so, ouch.

Re:How does it compare to a vending machine?

[santathehutt]

Back in the 90's I worked for a company that built coin changers and acceptors. Even back then they were using a more advanced method than the one you describe. The acceptor was actually the part that determined what type of coin was inserted and would reject it if it was a slug. The acceptor worked on the same principle as a metal detector. Since coins are made up of a unique mix of metals the acceptors could be "tuned" to accept a certain coin by dropping versions of that kind from different years and differing conditions. This would create a range of values for each coin. When a coin is dropped into the acceptor it gets a reading of the coin. If it is in the range of one of the coins the acceptor is programmed to accept then the coin is routed to the proper coin tube or the cash box if the tube is full. Otherwise it will be rejected as a slug. The acceptor is actually plugged into the top of the changer as a complete unit. For what it's worth I did see an acceptor there one day that worked similar to the way you described, but I believe it was from the 70's or early 80's.

Re:How does it compare to a vending machine?

[Anonymous Coward]

That should be "intents and purposes". And "begs the question" is wrong. Did you loose your grammar book?

Re:How does it compare to a vending machine?

[Anonymous Coward]

"loose" -- idiots the way down, I guess...

Re:How does it compare to a vending machine?

[Anonymous Coward]

I don't think the magnetic approach would work in the UK, all new 1p's and 2p's are magnetic. Makes it fun when you've got a very powerful magnet and a few 'coppers', creating towers/shapes etc.

Re:How does it compare to a vending machine?

[Anonymous Coward]

Godwin's Law

Re:How does it compare to a vending machine?

[Beyond_GoodandEvil]

Back in the 90's I worked for a company that built coin changers and acceptors. Even back then they were using a more advanced method than the one you describe. The acceptor was actually the part that determined what type of coin was inserted and would reject it if it was a slug. The acceptor worked on the same principle as a metal detector. Since coins are made up of a unique mix of metals the acceptors could be "tuned" to accept a certain coin by dropping versions of that kind from different years and differing conditions.
Interesting, that might explain why a 60's vintage silver dime was rejected by a vending machine. Didn't realize it was a silver dime until I plucked it out and saw the vintage and the lack of shine.

Re:How does it compare to a vending machine?

[bitt3n]

I know that's the way it used to work. Have they dumbed down the machines recently?

yes, as a result of the 'no vending machine left behind' policy, all vending machines now house a child left behind by the no child left behind policy, who bites each coin between his teeth to test its authenticity.

Re:How does it compare to a vending machine?

[jnork]

Correct, he meant "differ". If I were being a grammar Nazi I'd ding him on "For all intensive purposes" in his sig, too, which should be "For all intents and purposes."

Fortunately I'm not being a grammar Nazi tonight so I won't mention either of those.

Re:How does it compare to a vending machine?

[jnork]

Hmmm, maybe. Honestly though I don't consider the term "Grammar Nazi" really the same thing, it's just an expression. Like calling somebody a "bitch" would refer to unpleasant behavior and not actually literally accuse that person of being a female dog. Unless you're talking to a werewolf, maybe. :) "Grammar Nazi" is just a way of saying somebody is being unpleasantly and unnecessarily pedantic, sort of like I'm being now.

Go ahead and claim Godwin if you like but I disagree. Just sayin'.

Re:How does it compare to a vending machine?

[jnork]

I once was present (1990s) when a colleague dropped a silver quarter into a vending machine. I immediately recognized the sound as the quarter was tossed into the rejected coin bin and traded it for a clad quarter.

Unfortunately my modest collection of silver coins and a few silver certificates was stolen. What's really irritating is the thieves probably didn't even recognize their value, and I expect just spent them as cash.

Then again perhaps I should be glad they didn't profit more than they did, and eventually other collectors will snatch them up.

Re:How does it compare to a vending machine?

[tlhIngan]

I've got a great algorithm for scanning notes with the sensor from an optical mouse; the only thing I can't figure out is how to make sure the mouse knows where it is on the paper...

Actually, you know accurately movement, you're just missing a starting point.

So the simple answer is to assume a square piece of paper whose edge is 2 bills wide - and start at the center. Then you can scan in any bill, regardless of whether it was portrait, landscape, or what corner they started scanning at. Assume that's your starting point, and then notice how the mouse is moved when mapping the images to where in the scanned image the image should go. (The movement detection is identical to how optical mice work, and as long as there's overlap, you can detect movement speed and position, and map the new image appropriately).

Once the scanning is done, you can crop out the areas that aren't scanned.

Re:How does it compare to a vending machine?

[istartedi]

Release the hounds, and let the grammar nazis lose!

Re:How does it compare to a vending machine?

[Anonymous Coward]

Anyone who thinks intents and purposes is intensive purposes should not have a grammar nitpick as a sig. Dumbass.

Re:How does it compare to a vending machine?

[sFurbo]

The danish mint make a point out of making a lot of special 20 DKK coins (about 4 $), enough that they want get snatched up (I think it is typically 1 million of each, in a population of 5 million). They do this to make it possible to find that (not so) rare treat every time you get money back. Whenever I find one, I eagerly use it, to make sure more people will find one :-) It's not like they will ever be valuable, there are simply to many made.

Re:How does it compare to a vending machine?

[Anonymous Coward]

Way to miss the point again, Batman. Transitive vs intransitive isn't like flammable vs inflammable.

Re:How does it compare to a vending machine?

[Anonymous Coward]

2's compliment arithmetic: "127 + 1 = -1, and those shoes are fabulous. you go girl!"

Re:How does it compare to a vending machine?

[ulathau]

The ones used in gaming machines in australia for the last 4 years use lasers to weigh the coin and various things.

Re:How does it compare to a vending machine?

[Alioth]

I think you need to recalibrate your humour/sarcasm detector on the subject of the parent poster's sig. It's obvious it's a joke.

Sarchasm: The gulf between the teller of sarcastic wit and the person who doesn't get it.

Re:How does it compare to a vending machine?

[base3]

And the U.S. five cent coin was taken by coin acceptors in the U.K. as a 20 pence coin.

Re:How does it compare to a vending machine?

[Drishmung]

Yes, that would make sense. I'm remembering an article I read in an old Popular Science in my childhood, and more sophisticated techniques 'upcoming' were described then, including the metal detector.

I couldn't see how "just magnets" (as described in the comment I replied to) would work if only because there needs to be some way to sort by coin type. Every vending machine I use figures out the value of the coins I've fed it.

Re:How does it compare to a vending machine?

[ibmjones]

Let me guess: married?

16x16 pixels?

[Anonymous Coward]

Somehow I doubt a 16x16 pixel grayscale sensor is going to detect counterfeit coins any better than the human eye, but maybe I should read TFA before I jump to judgement...

Re:16x16 pixels?

[logjon]

You could also try not missing the point. Or the the part of the summary that says "with a success rate comparable to that of an expert. Or the point, that being that sensors are cheaper and generally more easily employable than people.

Re:16x16 pixels?

[CannonballHead]

generally more easily employable than people.

And haven't formed labor unions. ;)

Re:16x16 pixels?

[pz]

Somehow I doubt a 16x16 pixel grayscale sensor is going to detect counterfeit coins any better than the human eye, but maybe I should read TFA before I jump to judgement...

And maybe before posting, too? Just a suggestion.

Generally, if you're about to post something that is along the lines of, "this couldn't possibly work because ..." without (a) having read the article, and (b) being an expert in the field, best to think twice.

Re:16x16 pixels?

[Anonymous Coward]

Yet.

Re:16x16 pixels?

[gyrogeerloose]

And haven't formed labor unions.

Have you not heard of the International Brotherhood of Laser Devices? Silly human; you will be among the first to bow down to your coherent light overlords.

Re:16x16 pixels?

[Anonymous Coward]

You don't have to be an "expert in the field" to (a) know how a 16x16 CMOS sensor works and (b) understand the relative efficacy of a sensor vs. a trained human. Am I missing the point? Quite possibly. However, nothing I said was inaccurate and at least my post didn't have three comma splices.

What exactly constitutes an expert on CMOS sensors and why does one have to be an expert on them to know how well they work in various applications?

Re:16x16 pixels?

[Anonymous Coward]

without (b) being an expert in the field, best to think twice.

If ppl took this advice there would be no comments on slashdot

Re:16x16 pixels?

[jnork]

Ah... so the sharks are just minions for the lasers!

Re:16x16 pixels?

[pwfffff]

Grats! The whole article was a lie, and you were the FIRST ONE to figure it out! Here's a million internet-dollars! YAAAY!

P.S.
He has just as many commas as he needs, though one is off by a few words and he left out a word. Protip: "if you're about to post something that is along the lines of, 'this couldn't possibly work because ...' without (a) having read the article, and (b) being an expert in the field" is a parenthetical; the main clause is "Generally [it's] best to think twice" (there's that missing word).

After detecting the counterfeits

[Anonymous Coward]

They use laser mice to *find* the fake coins, and they use laser sharks to punish the counterfeiters.

Fun fact #65

[dvh.tosomja]

Did you know that there are more than 260 different euro coins from 19 countries to present day!

Re:Fun fact #65

[Archangel Michael]

Let us imagine creating an obviously fake denomination, say the 2.50 Euro coin, and try seeing if anyone will call them on it.

We could make all sorts of fake (Not counterfeit) coins each one of "logical" but otherwise bogus coins, and start using them.

Of course, one would have to NOT actually complete the purchase with those coins or be subject to arrest for fraud (or similar charges).

Re:Fun fact #65

[Anonymous Coward]

Some one did something similar in the states several years ago. They made $200 bill with President Bush's portrait and bought some ice cream at dairy queen accepting the change. Don't know if they were ever found but this person was http://money.cnn.com/2004/09/02/news/funny/200_bill/ and I found several other stories while finding that link so yes people would accept them, unless your average cashier in Europe is smarter than over here. Admittedly not a difficult task. On the other side of the coin we do have a $2 bill that you often risk yourself using, one man was held handcuffed at bestbuy for two hours in front of everyone until someone from the secret service got there and explained that the $2 bill does exist.

Re:Fun fact #65

[xaxa]

The only denominations for Euro coins are €0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1 and 2 -- eight different coins. All e.g. €1 coins look the same on one side (a map of Europe), but have different national sides -- an eagle for Germany, a harp for Ireland, etc.

Re:Fun fact #65

[zippthorne]

Just leave them on the sidewalk. Someone will pick it up and either get a laugh, or be the laugh.

Re:Fun fact #65

[sFurbo]

Just making them is probably illegal, even if you can prove you had no intention of using them. It is in Denmark, at least, but we don't use euros.

Re:Fun fact #65

[zoney_ie]

Well, the original members (plus maybe one or two others) produced a set of 8 coins each. Then after the EU expanded, eventually the common design was changed to not only show EU, but all of Europe on the 10c, 20c, 50c, E1 and E2 coins. Some of the newest Eurozone members will only have minted these coins though (plus the 1c, 2c and 5c which haven't changed in common design). Also there are commemmorative E2 coins - e.g. Treaty of Rome coins of similar but individual design by each state, and then national issues as well.

But if you included coins issued different years, there are far more (minting started in 1999 and some countries put year of minting on the coin, although many like Ireland just put 2002 on all coins minted before 2002).

Also Germany has more than one mint (for a start, former east Germany as well as western mint, but I think there are 3 total), and there is a letter on the German side of the coin denoting which mint the coin came from.

It's not as complicated as you would think though as there are only the old and new common sides, and people are familiar with the major countries they usually get coins from. Seldom here in Ireland for example you get coins from Finland, Greece, Malta, etc. - but commonly Germany, Spain, France, Italy - probably in that order - and to a lesser degree Portugal and Netherlands, and very occasionally Belgium, Austria and then further away/smaller countries. Of course if UK was in Eurozone, then here in Ireland we would most of all after our own coins have theirs (indeed UK 1p, 2p, 5p, 10p and 50p used to circulate in Ireland when we had Irish pound, until the redesign of the higher value coins).

Where do you bank?

[davidwr]

I've got a bunch of 1,8 coins I need to get rid of.

Re:Where do you bank?

[Anonymous Coward]

will swap you for my £23 notes.

Re:Where do you bank?

[hcpxvi]

Only if your £23 notes are sufficiently pornographic. (Bonus points to those who recognise the obscure UK TV reference.)

The conclusion from this

[Anonymous Coward]

If you compare a counterfeit-coin-detecting expert with a purpose-built handheld device, the answer is pretty obvious.

Until the day the people who print counterfeit coins buy a purpose-built handheld device, of course, and there's no expert around to reprogram the device because he jumped off a bridge after losing his job.

Training data set

[Anonymous Coward]

Just make sure you don't have any counterfeit coins in your training set. That would be awful.

Re:Training data set

[izomiac]

Perhaps that's why it can never surpass what an expert can do. Realistically, you can't train it on just freshly stamped coins, nor can you really be 100% certain that a coin that has been circulated is genuine.

Re:Training data set

[Anonymous Coward]

Perhaps that's why it can never surpass what an expert can do.

a) If you got a panel of experts to examine all borderline cases from a large set of coins, and used that as training data, there's no reason that it can't do better than any one expert by themself.

b) After scanning and expert inspection you could destructively analyse the borderline coins (using techniques such as cross-sectioning, melting down, and spectral analysis) - which presumably *would* be pretty much 100% accurate if you had accurate reference values available from the mint - and then correct the training data based on the outcome.

who would go through the trouble?

[FudRucker]

counterfeit coins? i am not a counterfeiter but if i was going to counterfeit any form of currency i would do 20s 50s & 100s US dollar bills, a lot of work goes in to making them so i figure if i was to go in to that sort of criminal activity it would be the denominations that brought the best return

Re:who would go through the trouble?

[DarkOx]

That is why you would get busted. The most frequently counter fitted bills are the smaller denominations ones, fives, and tens. The reason people don't subject them to nearly the scrutiny. All and all there is not that much counterfeiting going on, and chances are if you accept a small bill there is very little change tendered so you are only out the inventory. If you accept a large bill like a 50 or a 100 you stand to loose quite a bit; you probably give not only your inventory but tender real currency as change; so even though those are fakes less often they get looked at more.

Re:who would go through the trouble?

[Anonymous Coward]

i am not a counterfeiter but ...

Good thing you clarified this and emphasized the point, because naturally we all would have assumed you were a counterfeiter based on your participation in this discussion.

Re:who would go through the trouble?

[Registered Coward v2]

That is why you would get busted. The most frequently counter fitted bills are the smaller denominations ones, fives, and tens. The reason people don't subject them to nearly the scrutiny. All and all there is not that much counterfeiting going on, and chances are if you accept a small bill there is very little change tendered so you are only out the inventory. If you accept a large bill like a 50 or a 100 you stand to loose quite a bit; you probably give not only your inventory but tender real currency as change; so even though those are fakes less often they get looked at more.

Actually, the most counterfeited bill is the $20; probably because it is the highest denomination in common circulation. The $100 is the next.

Re:who would go through the trouble?

[belmolis]

Counterfeit $100s can be identified by the absence of cocaine residue.:)

Re:who would go through the trouble?

[imakemusic]

100s? Why not go all the way?

Other coin facts.

[nuckfuts]

Every year here in Canada we mint a 50-cent coin. I almost never see one outside of a collector's set, however. In fact, it's so unusual to see one in circulation I've seen cashiers refuse to believe they are real money.

Ironically, US coins are widely accepted in Canada. There are so many US pennies in any random pile of "Canadian" pennies that no one could be bothered to sort them out.

Also, although US dollars trade for more than Canadian dollars, it's not possible to obtain an exchange rate for coinage. The only way to cash in on those marginally more valuable US coins floating around is to take then down to the US and spend them there.

A bit of trivia that few people know is that Canadian and US coins "flip" differently. That is to say, if you orient the "heads" side of a coin like a portrait and want to see the reverse side correctly oriented, you would flip a Canadian coin about the "Y" axis, but flip a US coin about the "X" axis. Otherwise the reverse side will appear upside down.

Re:Other coin facts.

[Anonymous Coward]

Every year here in Canada we mint a 50-cent coin. I almost never see one outside of a collector's set, however. In fact, it's so unusual to see one in circulation I've seen cashiers refuse to believe they are real money.

Similarly the $2 bill - http://en.wikipedia.org/wiki/United_States_two-dollar_bill#Non-acceptance

Re:Other coin facts.

[kramerd]

Ironically, US coins are widely accepted in Canada.

Whats ironic about it?

Re:Other coin facts.

[nuckfuts]

We have a coin of our own that is not always accepted, whereas we readily accept US (foreign) coins.

You don't see the irony in that?

Re:Other coin facts.

[Marcika]

Ironically, US coins are widely accepted in Canada.

Whats ironic about it?

That Canadian legal tender is refused by cashiers (i.e. the 50-cent coin), yet foreign coins are accepted.

Re:Christmas gift.shoes,handbags,ugg boot,Tshirts,

[Anonymous Coward]

I'd like a pair of ugg boots so when I kick you in the ass I can hear you say "Uggg".

Get the fuck out dickwad.

I still want my money back for my buttplug, asshole.

You must work for a bank

[Anonymous Coward]

Or the government.

How

[SEWilco]

There are several methods.

1. Smash coin with mouse. If coin bends, it is fake.
2. Put mouse on balance scale. See how many coins are required to balance the scale. If the number of coins is different from the number of genuine coins required, at least one fake has been detected.
3. Use the coin to pry the mouse apart. Look for scratches exposing a different color on the coin.
4. Put the coin on the mouse. Burn the mouse. See if the coin melts.
5. Put the coin on the mouse. Pour on the coin an acid which does not affect a genuine coin. Check if the coin survived.
6. Line up coins the length of the mouse. See if the number of coins matches the number of genuine coins.
7. Use coins to buy a mouse. See if the cashier rejects any coins.
8. Use coins to pay for a call to the Secret Service. Report that someone might have used a counterfeit coin to pay for a phone call from this phone booth. Leave the mouse in the phone booth. Repeat until the "mouse counterfeiter" or the "mouse crank caller" is caught.

Re:Fun fact, not comlpetly true...

[MayorKusanagi]

There are not 260 'different' coins. Each state just changes the picture of the coins (except 1€ coin), but coins are still made the same way, materials, size, weight are equal in each country. That leaves just with 8 different coins if my memory doesn't fail me... 1,2,5,10,20 and 50 cents and 1 and 2€...

Re:Fun fact, not comlpetly true...

[KritonK]

Each state just changes the picture of the coins (except 1€ coin)

1€ coins also have different "picture" (i.e., national) sides: http://www.ecb.int/euro/coins/1euro/html/index.en.html

Egyptian coins and the 2 euro coin

[eleuthero]

It is fairly "easy" to pass off a variety of Egyptian currency as euros - while certainly something to be avoided, the 2 euro coin is very similar to an egyptian coin of ... I think... 30 euro cents value. I am not quite sure why anyone would want to go about counterfeiting anything of such low value unless they wanted to get their coke machine cokes for 30 cents as opposed to 1-2 euro. Add on the cost of getting caught and thrown in prison on whatever the European equivalent of felony charges is and...

Re:Egyptian coins and the 2 euro coin

[xaxa]

This guy earnt £300000/year, and 5 years in jail.

Love to see this for bills

[WindShadow]

Sure would be nice to see this for US paper currency. Many cash registers are PC based at the motherboard level, and could support an optical mouse just fine. What a great bit of Open Source software it would be to create and release a program people could run in business, etc.