The original slot machine was invented by Charles August Fey in San Francisco between 1887 and 1895 (the exact date is still up for debate). This machine was a huge hit in saloons and it is the first to have three spinning reels, a payline, and an automatic payout system. It also featured symbols like horseshoes and bells, as well as playing card suitmarks. Originally, Fey’s machines were programmed to only pay off coins when three bells lined up on the payline. The machines were prone to malfunctions, however, and a common issue was that coins would fall on an internal balance scale and cause the machine to overflow with currency. This problem led to the development of a new machine known as Money Honey that was electromechanical and used a bottomless hopper. It was the first machine to be able to dispense up to 500 coins without an attendant and it set slot machines on an illustrious trajectory that would eventually see them out-earn table games in Las Vegas casinos by 1981.
Today, there are thousands – and probably millions – of different slot machines. Many of these are found in land-based casinos, but you can also find them online. There are a variety of different types, but they all share the same basic structure. Slots have become so popular that they now account for more than half of all casino revenues. While it is difficult to pinpoint exactly how many people play slots, it is estimated that a whopping two billion dollars are spent on them every year.
A large part of the reason behind this popularity is that slot machines offer players a chance to win big money. The concept of walking into a casino with only a few pennies to your name and leaving a millionaire is an appealing one, and it has kept slot machines in business for decades.
As the popularity of slots grew, they began to take on a personality all their own. While the original machines only had a limited number of possible combinations, later manufacturers added more and more. These additional symbols increased the odds of winning, but they also limited jackpot sizes and overall payback percentages.
The Liberty Bell became so popular that it was soon being copied by countless other makers. The Herbert Mills Company, for example, started producing a machine called the Operator Bell in 1907 which had three reels and was similar to Liberty Bell. This machine was so successful that it was seen in just about every barbershop, bowling alley and saloon by the end of the decade.
The popularity of slot machines continued to grow, and in the 1980s, Tommy Glenn’s invention of a light wand was a game changer. This device, which was composed of a camera battery and a miniature light bulb, allowed slot operators to blind the sensor that keeps track of how many coins are being dispensed. Previously, slot sensors were not able to distinguish between individual symbols and a random combination of symbols had a ten times greater chance of occurring than any other symbol.