Vending machines read dollar bills by scanning them for security features like magnetism, fluorescence, and infrared reflection. The machine compares the bill against pre-stored data to quickly verify its authenticity, ensuring it’s real before accepting it. Let’s go over the specifics:
Fluorescence Detection
One of the most common methods for authenticating bills is fluorescence detection, which analyzes the paper quality. Real banknotes, like the U.S. dollar, are printed on specialized paper made from over 85% high-quality cotton.
Counterfeit bills, often produced using bleached paper, react differently under blue light. By shining ultraviolet light on the bill and using a silicon photocell to detect any fluorescence, vending machines can determine whether the currency is genuine or fake.
Magnetic Detection
High-denomination banknotes often contain magnetic ink, which vending machines detect using magnetic heads. These heads measure the magnetic properties of the ink and the bill itself.
Machines like the Apex 7000 use this method to efficiently and accurately authenticate bills, ensuring only genuine currency is accepted. The key to success with this method is precise calibration of the magnetic head to prevent false positives or negatives.
Infrared Penetration Detection
Infrared penetration detection works by analyzing the paper’s hardness, density, and ink thickness. Infrared light penetrates the bill, and the machine detects differences in the absorption rates.
Authentic bills and counterfeits absorb the infrared light in distinct ways, allowing vending machines to add an extra layer of security to their authentication process. Devices like the Platinum bill acceptor use this technique to prevent fraud.
Laser Detection
Laser detection uses a specific infrared laser wavelength to identify fluorescent characters hidden on legitimate banknotes. These characters, which are difficult to replicate, glow when exposed to the laser light, allowing the machine to detect counterfeit bills with high accuracy. This advanced method is highly effective at identifying even the most sophisticated fakes.
