Casinos rely on shuffling machines to speed up game play and limit repetitive motion injuries among dealers. Most of these computers-controlled shufflers produce random shuffles; however, occasionally patterns have been discovered which lead to doubts about their randomness.
Card shuffling machines are devices which take a full deck of cards, shuffle them together and distribute them amongst players in an efficient and faster-paced manner. By eliminating each player having to cut his or her cards for dealing, these machines reduce wait times significantly while simultaneously protecting dealers from being exposed to cheaters who might try tamper with or alter the cards prior to being distributed to players.
There are two main categories of shuffler machines, continuous and batch. Continuous shufflers shuffle an entire pack of cards continuously while batch shufflers do it all at once. The type of shuffle machine matters as its operation determines whether or not the deck created from that shuffle is random; continuous shufflers tend to produce flawed shuffling while batch ones are less likely to produce errors in this department.
Henry Ash invented some of the earliest mechanical shuffling machines, using gravity and friction to shuffle cards. These first shuffling machines relied on gravity and friction alone for card shuffling; some examples date back as far as 1878. His device consisted of a box which could be shaken to cause cards to fall through a comb into a lower compartment before being repacked back up into its upper compartment for another shake, simulating what is commonly referred to as “riffle shuffling”, an effective technique in both poker and blackjack card shuffling methods.
Eventually, inventors created more sophisticated machines to shuffle cards. Charles and William Gunzelmann patented in 1925 a rhombus-shaped device with two compartments to store cards; when shaken it would drop at various rates before being distributed by two small wings to players via two small wings – creating an unpredictable random shuffle. But even this device had issues.
More advanced machines employ electric motors to shuffle cards. These motors drive gears that spin disks covered with rubber that touch cards with friction between cards and disks that causes cards to stick together until pulled away – creating more accurate shuffling results than with simple riffle shuffling methods.
Modern shuffling machines feature electric motors as well as sensors to monitor each card as it is dealt. This technology helps prevent any manipulation with cards being distributed and detect if players try to sneakily place cards onto the table using sleight of hand techniques. Some casinos have started employing this technology in their blackjack games as it helps keep track of players.