US Patent 9275361 Out of stock sensor

A weight sensing system for retail shelves includes multiple shelves having an electrical communication and power distribution system, and weight sensors located on the top surfaces of the shelves and coupled to the electrical communication and power distribution system for detecting the placement of retail products on the shelves. A controller monitors real-time at-the-shelf inventory and issues alerts when a retail product becomes out-of-stock, is anticipated to become out-of-stock, or is misplaced on a shelf. Collection of real-time inventory data enables comprehensive inventory control at the shelf and in storage areas.