Abstract: A vehicle tracking system includes a wheel containing sensor circuitry capable of sensing various types of conditions, such as specific electromagnetic and/or magnetic signals indicative of particular wheel locations. The sensor circuitry is coupled to an RF transceiver, which may but need not be included within the wheel. The wheel may also include a brake mechanism. In one embodiment, the wheels are placed on shopping carts and are used to collect and monitor shopping cart status and location data via a wireless network. The collected data may be used for various purposes, such as locking the wheel of an exiting cart if the customer has not paid, estimating numbers of queued carts, and stopping brake activation events from occurring during mechanized cart retrieval.

Abstract: An embodiment of a light powered transmitter configured for broadcasting an electromagnetic control field to a region is provided. The transmitter includes a housing having a longitudinal axis. The housing includes a photovoltaic cell configured to generate electrical power in response to light and a rechargeable power source configured to store at least a portion of the power generated by the photovoltaic cell. The housing also includes an electromagnetic transmitter and a directional antenna. The directional antenna can be configured to broadcast an electromagnetic (e.g., radio-frequency) control field to a region. The directional antenna can be rotatably mounted in the housing such that the antenna can be rotated around the longitudinal axis. The housing can further include a transparent or translucent optical element configured to receive the light and converge at least a portion of the light onto the photovoltaic cell.

Abstract: A wheel for a non-motorized vehicle (e.g., a shopping cart) can include a housing assembly and a tread assembly. The housing assembly can be configured to sealingly house electronics or other components. The tread assembly can removably mate with the housing assembly such that the electronics or other components remain closed and/or sealed within the housing assembly when the tread assembly is mated or unmated with the housing assembly.