The laser currency detector adopts a dedicated laser and receiving device. The receiving device is a highly sensitive component, which is particularly sensitive to interference from the power grid, human body and light. The YUWEI portable laser currency detector uses a special anti-interference circuit in the low-dropout voltage regulator circuit designed by itself. It can essentially disconnect the stable output of the instrument’s working power supply from the interference signal from the city power grid, eliminating the interference signal from the city power grid. The interference and the electrostatic interference of the human body. In the signal circuit, frequency selection and filtering techniques are also used to further strengthen the anti-interference ability of the instrument. Therefore, the YUWEI portable handheld laser currency detector can work normally in a very harsh environment. The paper currency (RMB) inspection can be carried out accurately even under the direct sunlight of the high temperature in June.
Principles of Counterfeit Detector
Recognition is to distinguish between true and false by detecting the inherent characteristics of the renminbi. The money counter is a mechatronics product, which involves many fields such as mechanics, electricity, optics, magnetism, etc., and requires mutual cooperation in all aspects.
Fluorescence detection
The working principle of fluorescence detection is to detect the paper quality of RMB. The renminbi is made of special paper (containing more than 85% of high-quality cotton). Counterfeit banknotes are usually made of bleached ordinary paper. The bleached paper will show fluorescence under ultraviolet light (blue light with a wavelength of 365nm). The reaction (blue light with a wavelength of 420-460nm is diffracted under the excitation of ultraviolet rays), the RMB has no fluorescence reaction. Therefore, by irradiating the moving banknote with an ultraviolet light source and simultaneously detecting the fluorescence reflection of the banknote with a silicon photocell, the authenticity of the banknote can be judged. In order to eliminate the interference of ambient light on the identification of counterfeit, a set of color filters with the same transmission wavelength as the fluorescence reaction wavelength of the counterfeit banknotes must be installed on the surface of the silicon photocell.
In fluorescence detection, two issues need to be paid attention to: 1. Detect the shading of the space. External light entering the detection space will cause false alarms; 2. Dustproof of UV light source and photocell. There is a large amount of dust in the process of counting money. The dust adhering to the surface of the light source will weaken the detection signal and cause false negatives.
For the fifth edition of RMB, fluorescent characters can be detected at the same time (colorless fluorescent ink printing, using another silicon photocell to detect, the transmission wavelength of the color filter is the same as the fluorescent reaction wavelength of the real banknote) to improve the effect of forgery.
Magnetic detection
The working principle of magnetic detection is that some parts of the large denomination real banknotes (20, 50, 100 yuan) are printed with magnetic ink, and the magnetism of the moving banknotes is detected by a set of magnetic heads, and the magnetism is analyzed through the circuit, which can be distinguished The authenticity of the banknotes.
In magnetic detection, good friction between the magnetic head and the banknote is required. If the head is too high, the impact signal will be large, causing false alarms; if the head is too low, the signal will be weak, causing false alarms. The detection needs can be met by controlling the height of the magnetic head (guaranteed by processing and assembly) and installing a banknote pressing rubber wheel above the magnetic head.