Intelligent cash drawer unit or cash register and methods of operation therefor

An intelligent cash drawer unit or cash register having an openable cash drawer comprising a plurality of cups for receiving notes supported on a plurality of transducers operable to weigh the cups, a signal processor operable to process signals received from the transducers to determine a weight of the notes in the cups, and a sensor operable to detect whether the cash drawer is open or closed;

• wherein the signal processor is operable to detect a poorly placed note, the signal processor being operable to either (a) detect based on an output from the sensor that the drawer is open and process signals from the transducers when the cash drawer is open, to detect when the cash drawer is closed based on the output from the sensor and to store a most recent stable open reading and a most recent stable closed reading, to compare the most recent stable open reading and the most recent stable closed reading and where a difference in value between the most recent stable open reading and the most recent stable closed reading is greater than a predetermined value, to determine that a note is poorly placed;
• or (b) to detect based on the output from the sensor when the cash drawer is closed, to process signals from the transducers when the cash drawer is closed, and to store stable closed readings and operable to monitor the stable closed readings and determine monitored values of the stable closed readings, over a predetermined period when the cash drawer is closed and compare the monitored values of the stable closed readings and when a difference in value of the monitored values of the stable closed readings reduces by more than a predetermined value, to determine that a note is poorly placed.