There are thousands of banks in the world where currency notes are counted and packed in the denominations of hundreds. Job of counting and packing is done by a large number of people. The job of counting the currency notes is quite boring. Scientists have developed a machine which automatically counts and packs the currency notes. This machine is a wonder of electronics.
Working principles of a currency counting machine is shown schematically in the figure. The bundle of notes to be counted is placed on platform P-1. These notes are pushed in the forward direction by a feeding roller R-1. These notes are counted by a sensor S-1. Thereafter the notes pass through the rollers R-2 and R-3 and channel C-1. Through the channel the notes reach the sensor S-2. In case of any error in counting, S-2 will shut the motor automatically and display the mistake. After sensor S-2, rollers R-4 and R-5 pick up the notes and throw them into the slots of the centrifuge roller. These notes are released as they reach the platform P-2 and start stacking upon it. This platform is equipped with another sensor S-3 which indicates whether P-2 is empty or loaded.
It is a microprocessor based machine and hence its reliability is very high. These machines can not only count currency notes but also the coins. These are portable machines and can be installed anywhere. Nowadays these machines are being used by many banks.