2007-07-11 01:37:54 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Other - Science
Many moons ago, I won £5 on a one-armed bandit in Plymouth. It paid out £1 in UK currency, and the rest in Canadian one-cent coins. The crew of the Canadian ship that was in harbour got wise that their one-cent coins were the same size as our sixpence.
Things have moved on.
Coins are firstly weighed. Then measured. Then there are other checks which are a trade secret.
This is why, if you try to use a slightly worn or bent coin in a slot machine, it is rejected. It's a bugger when you need cigarettes from the pub machine !
2007-07-11 01:57:03 · answer #1 · answered by Bunts 6 · 2⤊ 0⤋
There are many ways and as technology improves so do the technique.
1) the coins mass
2) since all coins are made of metals and all metals have resistance. An ohm-meter checks the coins resistance. If the resistance is within parameters, the coin must be the correct value!
3) in some denominations, different value coins have different sizes. e.g. dime (10 cents) is smaller than a quarter (25 cents)! so "WITHIN" the machine the quarter is not going to fit in the dime slot!
So a simple circuit using logic AND gate: If all three of the above values are TRUE then Coin is of correct value, if 1 value is FALSE the coin is rejected. In other words:
THREE INPUT AND GATE, 1 = TRUE, 0 = FALSE:
* = multiplication
1 * 1 * 1 = 1 Correct Value
0 * 1 * 1 = 0 Rejected
1 * 0 * 1 = 0 Rejected
1 * 1 * 0 = 0 Rejected
Many other techniques can be used!
2007-07-11 09:57:03 · answer #2 · answered by Lalu5 3 · 0⤊ 1⤋
Vending machines employ a series of tests to identify the denomination of coin and to detect forgeries, in older machines there were a series of "analogue" tests. One test is to check for magnetism Sterling and Euro 1,2 & 5 denomination are steel / copper alloy and therefore magnetic.
Theres also "the bounce" of the coin, effectively its a weight test- as the coin goes through the system, it reaches a drop. At the bottom of the drop, theres a rubber mat which the coin bounces off and the hight of the bounce measured.
There were also a series of slots that "filtered" the coins, smaller holes gradually increasing takes out the 1,2,5, 10, 20, 50 etc, in turn.
It's not infalliable, theres a (Latvian?) coin that is almost identical to the 2 Euro coin in appearance, weight, composition etc. And due to the regionallity of the Euro (French coins are different to Irish, German, Italian etc) can be difficult to spot in a large amount of change.
2007-07-11 13:16:59 · answer #3 · answered by Efnissien 6 · 1⤊ 0⤋
Some work on the diameter/shape, some work on the weight, and some work on both. Although some coins may appear at first glance similar, they are deliberately designed to be different in weight and size precisely to make it easier for automated machines like this to work.
2007-07-11 08:47:49 · answer #4 · answered by Graham I 6 · 0⤊ 0⤋
Don't things falling accelerate at 9.8 m/s^2 (acceleration due to gravity) until they reach there terminal velocity due air fiction. Not fall at 9.8 m/s.
As for the coin issue they probably use different methods due to size, shape and weight as each coin has different values for each.
2007-07-11 09:55:58 · answer #5 · answered by Anonymous · 0⤊ 0⤋
By the weight of the coin.
2007-07-11 09:56:12 · answer #6 · answered by JOHNNIE B 7 · 0⤊ 1⤋
by the weight of the coin
2007-07-11 08:42:42 · answer #7 · answered by Anonymous · 0⤊ 1⤋
by the weight of the coin
2007-07-11 08:41:09 · answer #8 · answered by char 4 · 0⤊ 1⤋
weight all coins are a different weight
2007-07-12 19:27:00 · answer #9 · answered by john s 5 · 0⤊ 0⤋
It measures the time it takes a coin to drop from A to B.
As coins are different weights the speed varies, but is always constant for each denomination.
2007-07-11 08:43:08 · answer #10 · answered by ALLEN B 5 · 0⤊ 6⤋