Slot machines have a fascinating and intriguing history. The history of slot machines is essential to understanding the true wonder of the free slot machines we have today. So lets go on a journey of discovery and check out. But because this type of machine had such a complicated payout system, it was difficult to manufacture these machines on a grander scale. The slot machines we know today were in fact a product of Feys second invention, which. The machines are digital, and were invented in the 1970s. From there, software designers in the 1990s created virtual slot machines which you can play on for free today. Who invented the slot machine? The answer is not so simple. Its basic form began around the late 1800 when Charles Fey of California created a primitive forerunner to what we know as video poker. The machine had a. The Liberty Bell slot machine became popular because it was simpler than the automatic poker machine and was mass produced around 1907 as it swept the United States with its popularity. The slot machines that are found in casinos.