How Slots Work

These machines were invented in 1985 and have since improved a lot. From being totally mechanical machines, they have changed to video, light flashing and computer controlled games. Here we deal with working of mechanical and also latest slot machines.

Functioning of the machine

The machine functions using complicated system of levers and gears. Main part is metal shaft which supports reels and is connected to handle mechanism. Breaking system halts spin action. The small censors decide position of reels which is conveyed to payout system. Besides this, a coin detector initial deposit and also unlocks handle. Although many efforts have been made by the manufacturers to rearrange various parts of machine, it has remained similar to what it was.

When handle of machine is pulled, this rotates hook mechanism. Kicker is then grabbed by hook, pulling it forward. When a catch at opposite end of kicker seizes control cam piece to move it forward. This revolves series of gears. Control cam is pulled back by a spring but is slowed reasonably by assembly of gears. On moving forward, it releases spring mounted plate extending across the machine. Stopper is pulled away from discs by control cam. Kicker continues moving to fix stoppers catchers located at cam plate. They hold stoppers in place for rotation of reels and discs.

Kicker keeps moving with help of handle which pushes disc forward for a short time. On pulling back handle completely kicker passes discs. It gets jerked backward at good speed. Then peddles on kicker hit notches on discs and this rotates reels speedily. Meanwhile control cam returns to original position. It then pushes cam plate back, releasing stoppers. Each stopper moves ahead and locks in notch, holding reel in position again.

Modern slot machines

These machines are designed to look like original models but the operations are different. Outcome of every pull is decided by a computer. Step motors which turn every reel is controlled by a computer and is stopped at a point decided by numbers generated by computer. Short electricity pulses drive motor and are controlled by computer.


As per law payback percentage of slot machine is always above a level. It differs in different regions but is generally close to 75%. This percentage is normally much higher, often from 90% to 98%. This does not exclude progressive slot machines. Because of higher payouts more people are attracted to it. Some people are of the opinion that slot machines placed at airports and prominent places have comparatively much lower payout.