How Do ATMs Always Give the Right Amount of Bills Each Time?

Illustration for article titled How Do ATMs Always Give the Right Amount of Bills Each Time?

All I ever want in life is for an ATM to spit out an extra 20 dollar bill one time. This never happens! Vending machines have given me two bags of chips. I’ve gotten an extra chicken nugget here and there. Sometimes even the glorious onion ring in an order of fries. But the cash machine never messes up for me. Here’s how it manages to do that: with a series of rollers—some serrated, some smooth—that send the bill to a conveyor belt to get scanned with a sensor.

Share This Story

Get our `newsletter`

DISCUSSION

I actually received the elusive “extra $20" one time at an ATM, it was folded over the bills I was supposed to receive. I promptly took it into the branch and turned it in, where the woman who didn’t get the $20 was trying to convince the bank manager that she in fact did not receive the money. He took it from me and handed it to her with a thank you to me. I think he gave me a free coffee mug. To anyone who says they would have kept the money I ask: Is the price of your morality really that low?