Vending machines are a great mystery to some people, most especially kids. How does it work? How does it know that you put in real money? How does it know the value of the paper bill that you inserted in it? To kids, some believe that there is a real live person inside the machine who checks the money that a costumer puts in, makes the coffee, or pushes the snack that the customer wants. Pretty good theory huh? But really, how does a vending machine work? Its no magic but its not exactly rocket science either.

A vending machine is really just a simple robot in the form of a big box that holds a lot of good stuff like beverage and snacks. It has a central computer inside that acts as its brain, like a computers central processing unit or the CPU. It controls every action of the vending machine depending on the commands of the customer who inputs the money and chooses what to get from the machine.
The central computer or the brain of the vending machine is a small box with a keypad. The user or the owner of the machine can program it through this central computer, and tell it what to do when certain buttons are pressed.
Then theres that slot where you put in the money, the validator. It has a rubber treadmill that drags the bill into optical scanners. These optical scanners are little cameras that send a picture of the bill to the central computer. The central computer examines the picture and looks for special marks. The validator then gets a message from the central computer, telling if the money is real or not. If its real, the validator also gets the message from the central computer about the denomination of that specific bill.

How about coins you ask? Theres the coin mech for that. The coin mech works just like the validator, but it only reads coins. When a coin is inserted, it rolls in a series of electromagnets that create an electromagnetic energy field. This field categorizes any metal coin that passes through it. Because coins are made up of different kinds of metals and vary in size and thickness, the coin mech is able to identify what kind of coin you inserted. Stacking the coins by their denomination, the coin mech sends a message to the central computer and tells it how much money the buyer put in the machine.

Now, is there really someone inside who pushes the snacks and mixes the coffee? Sorry to burst your bubble, but there isnt. The products like junk foods and chocolates sit on pairs of metal spirals, meanwhile these metal spirals sit on adjustable shelves. The spirals are connected to a gear and that gear is connected to an electrical motor. When the motor turns, the spirals rotate, pushing the food out of the stacks.

At the bottom part of the machine is a line of laser beams. The laser beams are aimed at an electronic light sensor. When it senses an object that has dropped down to the bottom of the machine, it breaks the path of some of the laser beams.

At the bottom of this machine, there is a line of laser beams. Each laser beam is aimed at an electronic light sensor. When something drops down to the bottom of the machine, it breaks the path of some of the laser beams, sending a message back to the central computer so it knows that you got your food. When it doesnt sense anything, the computer automatically turns the spiral again. After three failed attempts, the computer tells the coin mech to return the money.

Simple and easy! Next time that you buy something from a vending machine, you now know how it works and tell your friends about it.