Monitoring the level of a stack of coins

摘要

The level of a stack of coins in a stack tube is monitored by an ultrasonic transducer disposed above the stack tube. The transducer directs a train of ultrasonic pulses down towards the top of the stack and measures the transit time between the emitted and reflected pulses. The monitoring apparatus is particularly suitable for use in a gaming, amusement, vending or change machine which has a number of stack tubes from which coins are payed out by a payout device under the control of a control unit.