How Do Vending Machines Know What Coin Or Dollar Bill You Insert?
size and weight with coins, in England the more the bill is worth the larger it is so it can tell that way, get a $1 bill and a $10 bill and its likely they diff sizes, also if you look in the top right corner of a $1 bill you can see a tiny spider
Tags: Bill, Coin, Dollar, Insert, Know, Machines, vending, What