How does a vending machine know your coins?
Coin Detective
How does a vending machine know your coins?
You slide a coin into the slot, and somewhere inside the machine, something decides. Not a quarter. Not a button. A coin. How does a chunk of metal know what you just gave it?
Inside, your coin drops onto a ramp — and immediately, the machine starts its detective work. First test: weight. The coin rolls past a tiny scale built into the chute. A quarter weighs 5.67 grams. A nickel weighs 5 grams. A penny? Only 2.5. If the weight's wrong, a trap door opens and your coin clatters straight into the reject slot.
