How do vending machines recognize coins?

With the acceleration of the pace of modern life, in order to save time and improve convenience, we can often see vending machines in subway stations, campuses, squares, etc., such as these: 　　 I believe that many small partners have done such things, just take A game coin similar to a coin was dropped into the vending machine, expecting a wave of'fishing in troubled waters', but the vending machine's 'human spirit' relentlessly spit out the game currency. So the question is, how does the unmanned vending machine recognize that the coin is thrown in instead of the game currency, is it 1 yuan or 5 cents? Many friends said that this should be weight sensing!?　　In fact, The vending machine works according to a set of precise and rigorous modes, instead of relying on us to give out the coins, Duang’s sound, a certain magical weight sensing device is activated, and the coin information is obtained.　　The vending machine is mainly composed of four parts: closed shelf, coin chute, coin divider, and circuit board.　　 After we insert the coin into the coin chute, the coin will pass through two light sensors. When no coin passes by, the two light sensors output signals at one end and receive signals at the other end. It feels very comfortable. When a coin passes, the signal will be interrupted. According to the face value of the coin (1 yuan is obviously larger than the size of 5 mao), after the coin is completely passed, the time difference generated by the signal will be different. Coin currency value. At this point, some friends are puzzled. According to this, I can pass the light sensor with a small cylinder and a coin? 　　 In theory, this is the case, so in order to avoid this situation, The clever designers arranged a second level.　　 That is two electromagnets, specifically, two energized copper coils. Electromagnetic knowledge tells us that a magnetic field will be generated around the coil after it is energized.　　Coins passing by will naturally cut the magnetic field formed by the energized coil, which will change the original current of the coil. Different metals cut the magnetic field, resulting in different changes in the current of the coil.　　 With this trick, the coil can know what kind of metal the coin contains.　　 After passing these two levels of 'testIf you have passed two levels, congratulations, the coin 'pass through the level' successfully, the coin divider will reunite it with similar friends, and you can get the goods 'pass through the level' failed, then sorry, invalid coins will be divided The device spit out and dropped to the refund point. But everything is not absolute, and occasionally there will be 'fish that slip through the netAt the same time of convenience, it further reduces the possibility of receiving counterfeit money.　　 This article is organized by automatic vending machines, and the views in this article do not represent the views of this site. Previous article: The development of unmanned vending machines is unstoppable!