Monitoring device.

摘要

A supermarket trolley monitoring system is provided for detecting shopping items on a lower shelf of the trolley 35 as the trolley moves through a check-out station. Three transmitter/receivers 30, 31, 32 are provided. The first 30 and third 32 at level A respond to light reflected by a panel 36 on the side of the trolley. The system is turned on when the panel 36 passes the first transmitter/receiver 30 and off when the panel 36 passes the third transmitter/receiver 32. The second transmitter/receiver 31 is mounted above A and if any object is detected while the system is ON, by reflection of the beam from the object, a warning is provided to alert a check-out assistant and/or a shopper that an item is present on the lower trolley shelf which may not have been entered in a till. <IMAGE>