Most slot machines in land-based casinos still use a sensor to determine how many coins or bills are being inserted. By interrupting these sensors with a pocket laser light you can make the machine think you're inserting coins or bills while you aren't.

Key Takeaways. Gambling is not a good alternative for earning extra cash. Each game you play at a casino has a statistical probability against you winning. Slot machine odds are some of the worst, ranging from a one-in-5,000 to one-in-about-34-million chance of winning the top prize when using the maximum coin play.