Comments on: How Do Vending Machines Know What Kind Of Paper Bill I’m Putting In The Machine?

By: Aj

Aj — Sat, 09 May 2009 16:46:52 +0000

There’s an electronic strip in the bill that tells the machine how much it’s worth

By: BodybySt

BodybySt — Sat, 09 May 2009 16:46:52 +0000

There’s a little “dollar identification monkey” in there. Clever little fellas.

By: The Fool.

The Fool. — Sat, 09 May 2009 16:46:52 +0000

Visual recognition.

By: Matthew

Matthew — Sat, 09 May 2009 16:46:51 +0000

That’s a cool question!
The first generation of machines used a magnetic head, like those in audio cassette players, to read the ink on a dollar bill.
Newer magnetic readers float above the surface of the bill and can distinguish between copier ink and Treasury ink by measuring not just the magnetic field but the pattern of magnetic particles within the ink, which serve as a sort of fingerprint.
These devices also analyze the shadows cast by various parts of a bill. Each sensor focuses on specific spots in a narrow swath of the bill as it passes by. (Precisely which parts of the bill are looked at cannot be revealed so as not to abet counterfeiters.)

By: Simon L

Simon L — Sat, 09 May 2009 16:46:51 +0000

Magnetic Strip
If you are using a Sterling note, you can see the strip across the side where the silver lines are.
The same for euros
The dollar has the same, but it is just not as visible as the others.
You will find if you hold the note up to the light you will most likely be able to pick out where the magnetic strip is.

By: crankyis

crankyis — Sat, 09 May 2009 16:46:51 +0000

scans the number on the bill. at least it used to, cause you could put a $2.00 bill in a poker machine, and it would read as a $20 until they figured out what we were doing! LOL…

By: Baby Water Shoes

Baby Water Shoes — Sat, 09 May 2009 16:46:51 +0000

I believe there is a little magnetic strip in every bill, differing per amount of bill.