How does a coin operated washer know how much money has been put in it?

Answer by  Halpern (63)

The washer has sensors that detect the number and type of coins inserted. Coins must be a specific size and weight to trigger the sensor, or they will be rejected. The sensor also tests for magnetism - coins are not magnetic, so anything magnetic (like a washer) will be rejected. The mechanism tracks the number of valid coins deposited.

Answer by  marie1217 (5)

There is a sensor built into the machines coin box, so its knows how much has been inserted.And it will only takes quaters no other types of coins for payment.