Patent ID: 8606501

Claim:
A system for monitoring shopping cart usage in the vicinity of a store, the system comprising: a plurality of access points mounted in a vicinity of the store; and a plurality of shopping carts, each shopping cart including a wheel assembly that comprises a battery-powered cart transceiver that is configured to communicate wirelessly with the access points on a wireless network, each cart transceiver configured to operate as a uniquely addressable node on the wireless network; said access points and cart transceivers programmed to communicate with each other on said wireless network using a non-standard wireless communications protocol in which the cart transceivers (1) generate received signal strength (RSSI) measurements based on transmissions from the access points, and (2) use said RSSI measurements to detect entry into particular zones that correspond to particular access points, wherein each cart transceiver is configured to modify its communication behavior in response to detecting that it has entered into a zone corresponding to an access point.