How Slot Machines Prevent Tampering – And The Tech Casinos Use

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Slot machines are a classic icon of casinos worldwide and have a reputation for creation multi-millionaires in a single spin. Just one nickel could transform your fortunes for life! Slots are hallmarks of Las Vegas, Monte Carlo, Atlantic City and Macau – and their presence is a must for a developer building a new casino.

Players love casino slot machine gambling. Grabbing either chips or coins, heading over to the reels, and plunging the arms to test your luck is one of the most popular activities in Vegas.

But there are some players who seek to game the system by tampering with the slots. Thankfully, casinos have developed anti-tamper slot machines over the years that combat this illegal activity and ensure players who spin lawfully get a fair chance of winning the jackpot.

How Slot Machines Work

Before we look at what casinos use to prevent slots being tampered with, it’s worth us looking into how slot machines work. Slot machines are effectively a computer program built into a cage that has a display from which the player can see if they have won or lost on a bet. The player places a coin into the machine, pulls the lever or presses a SPIN button, and watches the icons on the display reels spin round.

When the reels stop, any matching icons on one of the slot machine’s paylines will lead to a payout. There are other intricacies to one arm bandits – such as bonuses, extra reels and additional jackpots – but this is the fundamental way a slot is played.

Wins payout as a flurry of coins when the randomly-generated algorithm built into the game falls on a winning combination. There is no predictable sequence in slot machines – the game determines if you’ve won or not depending on which piece of randomly-generated code is triggered when you plunge the lever.

Slot machine in Las Vegas

Slot machines act as a faraday cage to prevent tampering

How slot machines prevent tampering

So, now you know how slots work, it’s time to look at how manufacturers prevent them from being tampered with. Here are some of the high-tech solutions to ensuring fair casino play…

  1. Con Matching Tech
  2. Faraday Cage
  3. Eprom
  4. Coin Dispenser

Coin Matching Tech

When you place a coin in a slot machine a scanner will compare your coin with the one that went before. Doing so ensures only the same coin each time can be successfully wagered. If the game only accepts nickels, then it will reject quarters.

Faraday Cage

A faraday cage is a metal structure that electronic impulses cannot penetrate. That’s why if your car is struck by lightning you won’t be electrocuted, as the car’s structure protects whatever is within from the electricity. And the metal cage of the casino slot machine works in just the same way. Criminals seeking to zap slot machines with electric impulses to mess with the internal algorithm won’t get far.


The EPROM is a chip placed within the slot machine that runs the game and sets the algorithm. It’s effectively the slot machine’s software. It has a tamper-evident sticker attached to it and can only be reprogrammed using ultraviolet light when detached from the machine. To do that, gaming authorities must be present to ensure there are no errors or illegal tampering.

Coin Dispenser

Gone are the days where you can kick or shove casino slots in the hope of tipping some coins out of the dispenser. These days slot payouts require the coins to travel up a dispenser, where a light sensor counts the number of coins to ensure the correct prize, and then down into the well at the bottom of the machine. The tech also means you can’t simply stick your hand up the machine in search of coins.

Reel Sensors

Most slots reels are cased behind plexiglass but for those that are ‘open air’ reels, sensors are placed on each reel to detect movement from players. If you attempt to move a reel then your game will be void and you could lose your winnings from earlier in your spin.

Online Slots

If you thought it was hard to tamper with casino slot machines then for online slots it’s almost impossible. Online slot machines benefit from having zero hardware – you can’t physically manipulate your computer or phone screen to aid your gameplay. What’s more, the algorithms for online slots are even more complicated – and that makes online casino play a reliable, safe and secure platform to enjoy gambling.

Can’t get enough of slots? Find your new favorite reels with our online casino reviews.

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