Abstract: An apparatus includes a platform or other accessory that is supported by one or more transducer assemblies using piezoelectric transducers. In one implementation, a saddle structure provides mechanical support to a platform while transferring force from a load onto a portion to which a pair of piezoelectric transducers are affixed. As a load on the saddle changes, the resulting change in strain on the portion produces signals from the piezoelectric transducers. In another implementation a beam provides mechanical support to a platform or other accessory. A pair of piezoelectric transducers are affixed near a strain concentrator, such as a hole in the beam, produce signals indicative of a change in load on the beam.

Abstract: An impulse strip including a plurality of clips, hooks or other features for attaching items to the impulse strip also includes a plurality of switches associated with each of the clips, hooks or other features. The switches are in communication with illuminators or other indicators that are arranged in an array. When an item is loaded onto the strip, or removed from the strip, a switch may be opened or closed, causing one of the illuminators in the array to be activated or deactivated accordingly. An image captured of the illuminators is processed to determine which of the illuminators is activated and which is deactivated, and an inventory level of the strip may be determined based on the statuses of the respective illuminators corresponding to the clips, the hooks or the other features of the impulse strip.

Abstract: An apparatus includes a platform or other accessory that is supported by one or more piezoelectric transducers. As items are placed on or removed from the accessory, the piezoelectric transducer generates an electric charge that is representative of a change in weight. An amplifier receives the charge and provides output voltage that can be sampled to determine a weight value. In one implementation the platform may be supported by a transducer assembly comprising a frame and a pair of piezoelectric transducers on opposite sides of the frame. Signals from the pair may be used to compensate for environmental effects on the assembly, such as changes in temperature. The piezoelectric transducers and associated circuitry are extremely energy efficient, consuming little electrical power during operation.

Abstract: This disclosure describes, in part, systems for tracking the removal of shopping bags or other items from a dispenser. Folded shopping bags are stacked in a holder so that a front shopping bag can be removed by pulling it along an axis that is parallel to the length and/or width dimension of the shopping bag. A motion sensor is positioned to sense movement of the front shopping bag as it is removed. Control logic monitors and/or analyzes data or other signals from the motion sensor and determines whether movement of at least a threshold distance has occurred. If movement of at least the threshold distance has occurred, the control logic concludes that a shopping bag has been removed and generates a corresponding event notice. Other system components may respond to the event notice by applying a charge for the removed shopping bag or by performing other actions.