Components That Make Slot Machines Tick

Slot machines have undergone dramatic improvements over the past century, with mechanical slots being almost completely replaced by fully computerized machines. When slots first appeared, their principle of operation was entirely mechanical. The machines used levers, springs, and gears to work.

Then, a new generation of electromechanical games emerged. They used solenoids, motors, and electromagnets in addition to the original moving components, significantly improving the gameplay. But game manufacturers did not stop there. Today’s slots are fully computerized and rely on components like computer chips and Random Number Generators (RNGs).

Differences between Mechanical and Modern Video Slots

Mechanical Slots
Modern Video Slots

The theoretical payback percentages in early machines were based on the number of symbols each spinning reel contained coupled with the payout for each winning combination.

The introduction of the RNG technology in the early 1980s completely changed the way slots play.

The machines were rather bulky. They contained huge spinning reels with symbols that were set in motion by the pull of a lever. The reel number was usually limited to three because the addition of more rotating drums made the machines very difficult to install.

Traditional mechanical slots eventually gave way to modern machines that rely on computer chips and software instead of gears and springs. Modern games have no mechanical parts whatsoever.

A coin detector registered the number of coins players inserted into the machine along with their denomination. By pulling the lever, the player triggered a spring-based mechanism that consisted of three components, called a hook, a kicker, and a control cam.

These components operate together to release the drums from their resting position and determine how smoothly they rotate and with what force. Other mechanical components involved in the spinning of the reels include gears, notched disks, and stoppers.

They graphically simulate the rotation of the reels on a video screen after the player presses the spin button. The outcome of each round is determined by a microprocessor inside the video slot.

This enables game developers to incorporate more symbols and reels into the games, which, in turn, increases the number of possible combinations. Interestingly, video slots did not immediately become a hit on the casino floor.

Long strips containing symbols are glued on the reels with adhesive. Next to all symbols, there are notches called stops. The higher the number of stops associated with a given symbol, the greater the chances that it appears on a payline. Jackpot symbols usually have a single stop while blanks have two or more stops. Because of this, blanks hit far more frequently than symbols that pay out.

The reels come to a halt one at a time, which creates more suspense. The player is awarded a payout when all three reels contain identical symbols. However, the matches must occur on a payline for the machine to yield a payout.

Many players were wary of the new games because they had no trust in computers. The imaging was of low resolution and the slots lacked immersive sounds and bonus games to keep players interested.

This all changed in the mid-1990s when the first bonus-game slots hit the casino floors. Manufacturers like the Australian company Aristocrat Technologies launched slots that played on five reels and had bonus features like free spins. Players gradually grew warmer toward video slots, with Reel 'Em In by WMS becoming a massive hit in the United States in 1997.

Computerized Slot Machines

Modern slots are software-driven, which enables developers to incorporate more symbols, high-definition graphics, animations, and special features into the gameplay. There are several key components behind video slots, starting with the Random Number Generators (RNGs) that determine whether a spin wins or loses. Virtual reels are utilized, allowing for a higher number of paylines and more complex paytables.

Random Number Generators in Slots
The Virtual Reels
The Payline
The Paytable

Is It Possible to Count All Symbols on the Reels?

1Number of potential combinations

Modern slots utilize the Random Number Generator technology and virtual reels. This enables software developers to add a significantly larger number of symbols per reel. We regret to say there is no way for the player to count how many symbols a given modern slot uses. This makes it impossible to calculate the exact odds of winning or the number of potential combinations.

The RNG ensures the unpredictability of results. Contrary to popular belief, casinos cannot simply pre-program a given slot to reduce its theoretical payout percentage. Also, it is important to stress there are no hot and cold cycles with slot machines.

2Slot odds

The odds of the player are the same on any round. Slot odds cannot be quantified because spinners have no way of knowing how many symbols per virtual reel a particular game features.

3Pseudo-random results

And one final thing. The Random Number Generators built into most slots create pseudo-random results which, nevertheless, are chaotic enough to prevent players from discerning any repeating patterns. Thus, the long-term theoretical return percentages coincide with what players could expect from randomly occurring results.

Some players believe that in theory, the RNG can repeat the number sequence it generates at a given point. However, the RNG continues to spit random numbers even when the slot is not in use. Subsequently, this means there is no way for the player to establish with precision at what point in the number sequence the game is.