The first slot machine was developed in 1891 which was the forerunner to the modern gambling machine. Later, they got added into casinos as a diversion for casual gamers. Slot machine games, such as Book of Ra or the popular fruit themed slots don't require gambling knowledge, like the traditional table games known as blackjack, poker or craps where you need to know a set of rules. Eventually, slot machines proved to be a success and became the most popular in casinos.
The technology of slots was modified over the years. The classic mechanical designs have been mostly replaced by computer machines. But the game has remained the same.
The Classic Slot Machine
A classic slot machine is a structure of gears and levers. The central element is a metal shaft that supports the reels. This shaft is connected to a handle that gets things moving. The spinning reels stop with the help of a braking system and there are also sensors that communicate the position of the reels. These sensors can either stop the game, pause the game or start it.
One representative mechanics include three reels mounted on a central shaft. The shaft supports three notched discs, which are connected to the reels. A second shaft is below the central one, this one supports a kicker, which is a piece of metal comprising three paddles. The kicker paddles are lined up so they can push the notches on the three discs. The second shaft also supports some series of connected stoppers, that lock into the notches on the discs.
The kicker and the stoppers are both connected to the springs, which are held in a standby position. The kicker is behind the discs, while the stoppers are held against the discs, locking them in place.
From the player's point of view, the handle is pulled. There is a sound and the three reels start spinning. Then the first reel stops, followed by a second then a third.
The electrical machines came to the rise at around the end of the 70s when the first video slot was produced. Electrical machines work on similar principles. The reels are whirled by motors and the stoppers are triggered by solenoids, but basically, the game plays out the same way. Electrical machines are similar to vending machines, and it also comes with flashier light and sound displays.
There is another popular system in some machines where the discs have a series of metal contacts attached to them. When the reels stop, one of the contacts engages a stationary one that is wired to a circuit board. In this way, every hold on each reel will close a different switch.
Another, more advanced system uses photoelectric cells or photodiode. They are devices that generate a current when exposed to light. In this system, there is a series of holes in the rotating discs, all around their outer edges. The photodiode is positioned on one side of the disc and a light source is on the other side. As the disc turns, the light shines through the holes onto the photoelectric cells. This causes the cells to generate a pattern of electrical pulses. Based on this pattern an electronic circuit can determine the position of the reel.
Newer slot machines use computers instead of gears. They are designed to look and feel like the old mechanics, but they work on a different principle. The outcome of each pull is controlled by a computer inside the machine, not by the motion of the reels. The computer has some step motors that turn each reel and stop it at the predetermined point. The step motors are driven by short digital pulses of electricity controlled by the computer. But even though the computers tell the reels where to stop, in the heart of the computer there is a random number generator. The random number generator is generating a whole lot of numbers hundreds of times per second. Then the computer records the next few numbers from the random number generator then it feeds them through a simple program in order to determine where the reels should stop.
Some slot-machine variations are simply aesthetic. Video slots operate at the same way as a regular machine, but they have a video image rather than actual rotating reels. These are few popular slot machine variations. Game producers continue to develop new sorts of slots with interesting variations on the classic games. A lot of these games are built around particular themes. There are slot games based on popular television shows, history of mankind, popular video games, poker and many more.