Slot machines have been one of the most popular forms of gambling since they were first invented all the way back in 1894. Since the invention of this device, the very first slot machines have changed a lot, getting ever more advanced and offering new and exciting designs, bonuses, and ways to play. Today, most slot players prefer to play online, as online slots add even more variety and unique designs, but slot machines are still a popular fixture at casinos and slot parlours. 

In this article, our slot expert Joe Booth (read more here) explains everything you need to know about what goes on behind the reels. Most gamblers have pulled the lever to spin the machine at some point, but not many understand what happens inside to determine whether you win or lose. As a result, slot machines are something of a mystery, and there are plenty of crazy superstitions and myths surrounding them. If you want to understand these machines and how to win, read on for all the details. 

Mechanical Slot Machines

The first slot machine was entirely mechanical, using a relatively simple design that involved a pull lever and three wheels that would spin around a drum. All of the early slot machines were limited by their design, as the more complex you wanted to make the game, the more parts you would have to add. They’re very different from modern online slots, although they were just as popular.

The exact mechanism of a mechanical slot machine varies depending on the make and model, but the basic slot gaming design is as follows:

1. The player pulls the lever, which rotates a hook, grabbing hold of a part known as the kicker. The kicker is a piece of metal with three paddles that are designed to push the discs the reels are attached to.
2. A catch on the kicker’s opposite end snags and pivots a control cam piece forward. A sequence of gears attached to the control cam rotates as a result of this. 
3. The control cam is pushed back to its original position by a spring but is slowed by gears to create a mechanical delay.
4. A spring-mounted cam plate extending across the back of the machine is released when the control cam is turned forward.
5. Parts known as stoppers, which effectively keep the reels in place, are then pulled away from their position by the control cam. The stoppers are pushed against various catches on the cam plate while the kicker continues to move. These keep the stoppers in place, allowing the discs and reels to rotate freely.
6. The kicker paddles briefly push the discs forward. The bottom of the hook mechanism slides up against a slanted surface when the handle is fully retracted, and the kicker has passed the discs. The slant forces the hook to tilt forward, releasing the kicker.
7. The kicker paddles collide with the notches on the discs, rapidly spinning the reels.

The very first mechanical slots used playing card symbols, but over time, fruit symbols started to become more common, and these are still used on classic slots today as seen on online slots reviews. In the late 1920s, an innovative feature known as the skill stop was added where players could press a button to stop the reels at any time. While this was popular with players, it added a skill element to the games and fell out of favour with game manufacturers over time.

Electronic Slots

History was made in 1963 as the first electromechanical slot Money Honey was produced. With electronic systems, slot machines could gradually get more complex, adding additional reels as well as bonus symbols. Players no longer had to pull a lever either. Instead, they simply had to press a button, which was faster and more convenient. 

During this time, technology was improving at a rapid pace, and soon slot machines were entirely electronic with video display. The first video slot machine was introduced in 1974, and it wasn’t long before the graphics and animations were making these machines far more popular than their counterparts. With a video slot, the outcome of the game is no longer determined by a piece of machinery. Instead, a random number generator is used. 

With random number generators, video slots are fairer and easier to produce than traditional slots, and they can also be infinitely more complex. Modern slots are the result of years of successful slot design and include lots of special bonus rounds and features to draw players in. Although modern online slots are random, choosing the right games and understanding the rules are two of the easiest ways to master slots.