Slot machines are a gambling device with three or more reels that start to spin after a lever but nowadays button is pushed. There is a currency detector where players insert the coin to play. The machines give payouts depending on combinations of symbols that appear on the reels when they stop. Slot machines are the most popular casino activity and make about 70% of the average casino income.

First slot machines appeared in 1887. They were the machines with mechanical reels, only one is left now and it is displayed in Reno. Charles Fey from San Francisco, California, is the man who invented the first one-armed bandit that was a much simpler automatic mechanism that time. Charles Fey developed a machine with 3 spinning reels with a total of 5 symbols – horseshoes, spades, hearts, diamonds and a Liberty Bell that also gave the slot machine its name. Fey developed an efficient automatic payout mechanism.

In 1891 Sittman and Pitt from Brooklyn, New York, devised a gambling machine, a precursor of the modern slots. It had five drums with 50 card faces and the base of the game was poker. That machine proved to be very popular and soon there had been one or even more of those machines in lots of bars around the city. Often the prize was a free beer, cigars or drinks.

In 1964, the first fully electromechanical slot machine was developed, it was called Money Honey. And in 1996 WMS Industries Inc. invented the first video slot that could offer a second-screen bonus game.

Today there are a lot of slots available online. Any player is sure to find slots to their taste. There are classic, progressive, bonus, penny, multi line, video slots. Casinos often offer different promotions and online tournaments to make their place more attractive for players.

Modern slot machines are controlled by EPROM computer chips. Also new slots have top-of-the-line anti-cheating and anti-counterfeiting devices that are difficult to fraud. Every slot is managed by the Random Number Generator. After the Spin button has been pushed the computer spins the reels, then stops and the different symbols generated by the RNG appear on the reels.

Many well-established casinos offer their customers the opportunity to play for free so they can first try out their games before playing on real money.