Dear All,
I need help in making the electronic circuit of Magnetic Ink Detector which are used in fake currency detectors. Normally these circuits use a magnetic head (same as used in stereos), and make a beep sound when the magnetic part of the dollar is rubbed against the magnetic head.
Please help with circuit and component details.
Thanks in advance.
Sajeev snipped-for-privacy@gmail.com
US currency uses a magnetizable dust in one of the inks - black, I think. You can run the bill past a magnet and then past a magnetic head to check the magnetic "signature".
They are called MICR printing, Magnetic Ink Character Recognition; the scanning is done magnetically, not optically. You can buy remanufactured toner cartridges for laser printers in order to print MICR data on plain paper to create your own checks. It is possible, since banks in the US now store all checks electronically as 200dpi images, that MICR will give way to actual optical character recognition.
Magnetic ink on currency? News to me.
I've heard of it on checks, but that is not true as far as I know. Those numbers on the bottom edge of the check are special Optical characters.
-- Luhan Monat luhanxmonat \'at\' yahoo \'dot\' com http://members.cox.net/berniekm
Last time I had any contact with the check reader business, the encoding on the lower left of a check IS magnetic ink.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Jim,
Any idea why they did it that way? Seems that it would be much simpler to do it optically and elimate the need for special ink.
-- Luhan Monat luhanxmonat \'at\' yahoo \'dot\' com http://members.cox.net/berniekm
To avoid reading errors due to wild-ass signatures (such as mine :-) that overlap the numeric data.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
I just looked at my checkbook. The mag ink number runs right up under the signature line. Yep, magnetic, good idea.
-- Luhan Monat luhanxmonat \'at\' yahoo \'dot\' com http://members.cox.net/berniekm
I took out a dollar bill reader out of an arcade game, not needed at home. Took the reader apart. Sure enough, there is a magnetic head, positioned in the middle of the reader, so that it can detect the magnetic serial numbers, regardless of which way the bill is feed into the reader. And of course, it has a series of IR pairs, supposedly to read the data stream as the bill goes by.
Jack
I checked 50 euros and it sticks to a strong magnet in certain places,so yes,the ink does seeme to be magnetic.
Digital color copiers have for some time included firmware to recognize currency; try color copying a dollar bill. The machine will say "ILLEGAL SOURCE MATERIAL" or something of the kind and will not print anything.
Modern scanner driver software also has currency recognition built in. Manufacturers refuse to divulge the details. Use Linux to get around this.
Color laser printers encode the serial number, print date and other information in the hardcopy so your handmade Benjamins can be matched to the printer you bought in Staples.
It seems like, at one time, color copiers had special color sensors such that if you were copying currency, it would intentionally screw up the copy, or something like that.
But a decent scanner and decent printer...
I was talking with my brother about that one day, and he said he'd like to do $100's, and stick them in the change machine at the casino. I said, "I don't know - I think I'd almost rather be in trouble with the feds than with casino security."
Cheers! Rich
[...]
The US dollar has a magnetic ink on it. Some (perhaps most) venting machines that take US bills use a magnetic head to check that there is a pattern of magnetic ink down one stripe on the bill. They check that the pattern is about the right amplitude too.
The toner in copiers is magnetic. In the past some people could fool the machines with copies of bills. Even though I don't think there are any of those left, I'm not going to get specific.
The whole process is done in something no smarter than the smaller PICs.
-- -- kensmith@rahul.net forging knowledge
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