An electronic module detachably mounted on a shopping cart includes a scanner for scanning bar coded information on items selected for purchase, a data processing device for data storage and control purposes and video recording apparatus capable of recording a view of the selected item as it is scanned...http://www.google.de/patents/US4929819?utm_source=gb-gplus-sharePatent US4929819 - Method and apparatus for customer performed article scanning in self-service shopping
