Help summoning system for use by customer in supermarket involves transmitter activated by pushbutton on trolley producing signal detected by nearby receiver and relayed to position finding computer

摘要

A customer (1) who needs help presses a pushbutton (2) on a signal transmitter (3) e.g. on a shopping trolley. The transmitter may produce an audio signal with a frequency of 20 kHz. Receivers (6) may be positioned at intervals in the aisles between the shelves. The received signals may be fed to a position finding circuit (7). Signals from the position finding circuit are fed to an information display unit (8) which may guide a member of staff (9) to the customer who needs help.