Electro-optical paper dispenser controller having a variable gain

Abstract

A controller controlling the dispensing of paper currency including a microprocessor for controlling motors which feed a predetermined mix of paper currency from each dispensing device to a common acceleration device which advances bills to an output stacker. Each individual dispensing device dispenses the proper number of bills to the acceleration device. Apparatus multiplexes the control signals to the stepper motor. After the bills have been dispensed, the stepper motor is halted, and a home positioning sensor determines if the stepper motor has been halted in the proper position. Sensors provided at spaced intervals along the common acceleration device determine if bills have reached the acceleration device. The dispensing operation is repeated if bills do not reach the sensor. The sensors perform the dual function of sensing advancement of a bill and detecting overlapping or multiple fed bills. The adaptive technique conmpensates for changes in the sensor such as component aging and dust accumulation. An initializing technique is weighted toward the first bill dispensed and develops an average of the last group of bills. A technique initializes density values and adjusts sensor gain. A loss in voltage couples battery power to the system memories preventing data loss. Currency is dispensed through any one of three techniques including dispensing a minimum number of paper bills whose demominations amount to a predetermined sum; omission of one or more denominations from the dispensed bills making up a predetermined sum; and selection of any mix of denominations.