An article of apparel, a system, and methods include a structural material configured to enable the article of footwear to the worn on a body. A wireless transmission circuit is included and a piezoelectric generator is positioned with respect to the structural material in a configuration to be flexed to induce a voltage signal output. A voltage sensor is configured to sense the voltage profile and output a sensor signal indicative of the voltage profile. An electronic data storage, coupled to the voltage sensor, is configured to store voltage profile information based on the sensor data. A comparator, coupled to the electronic data storage, is configured to identify a change in the voltage profile information over time. The wireless transmission circuit is configured to transmit data indicative of a physical status of the article of footwear based on the change in the voltage profile information over time.

A dielectric elastomer power generation system of the invention includes: a power generation unit including a dielectric elastomer power generation element having a dielectric elastomer layer flanked by two electrode layers; a step-down unit including capacitors; a power storage unit for input of an output power from the step-down unit; and a control unit that controls the connection between the step-down unit and the power generation unit or power storage unit. The step-down unit includes first diodes and second diodes, where the first diodes form a circuit that connects the capacitors in series when the power generation unit is connected to the step-down unit, and the second diodes form a circuit that connects the capacitors in parallel when the step-down unit is connected to the power storage unit. This configuration serves to store the generated power more efficiently in the power storage unit, e.g., a secondary battery.

An athlete monitoring system includes body position beacons, a localized radar system, a foot force detection system, and a processing module. The beacons are positioned at various locations on the body of the athlete. The localized radar system creates a localized radar coordinate system in which the athlete is positioned and, at a first sampling rate, produces frames of body position data based on determining location of the beacons within the localized radar coordinate system. The foot force detection system generates frames of left foot force data and frames of right foot force data. The processing module correlates the frames of body position data, the frames of left foot force data, and the frames of right foot force data to produce integrated ground-body interaction data and athletic movement data.

A foot force detection system includes variable capacitors, drive sense circuits, a processing module, and a power unit. A drive sense circuit supplies a reference signal to the variable capacitor. It then generates a sensed signal regarding a characteristic of the variable capacitor based on the reference signal. It then converts the sensed signal into a digital signal. The processing module generates a digital impedance value for the variable capacitor based on the digital signal and writes the digital impedance value in memory. The power unit include a battery and a power harvesting circuit, where the battery and/or the power harvesting circuit provide power for the foot force detection system.

A vibrational lens is disclosed. The vibrational lens comprises at least two focusing plates each having a proximal and distal end. The separation between the distal ends of the at least two focusing plates is less than the separation between the proximal ends of the at least two focusing plates. The vibrational lens transmits, converges and focuses vibrational energy from a source to an energy conversion means such as piezoelectric crystals. The vibrational lens may also comprise a bimetallic structure to convert thermal fluctuations into mechanical displacement. The vibrational lens is suitable for use in a vibrational and or thermal energy harvesting system. Advantageously, the vibrational lens improves the energy efficiency of, for example, an internal combustion engine whilst mitigating the need for vibrational damping mechanisms and or thermal insulation.

Described is an energy harvesting system comprising a transducer that generates an electric signal from ambient energy, and a processor adapted to process the electric signal to determine and output a characteristic of a source of the ambient energy. The characteristic may be a spoken word classification.

A suspension assembly provides a suspension frame and a supporting frame, the suspension frame being movably coupled to the supporting frame. The suspension assembly further provides at least one flexure that links the suspension frame to the supporting frame. The suspension assembly including at least one stopper to limit movement of the supporting frame and the suspension frame with respect to each other.

Disclosed herein are self-powered and multi-modal sensing wearables. The smart wearables can comprise mechano-luminescence-optoelectronic materials, which can be used for self-powered sensing and energy harvesting.

Energy harvesters (EH) which can effectively harvest wasted vibrational/kinematic energy and convert it into electrical energy for battery-free sensor operation are described herein. The energy harvesters can be integrated with a power management circuit and a wireless sensor for monitoring wind turbine blades. The target application of the energy harvesters includes powering the wireless sensors used for wind turbine blade structural monitoring.

Aspects of the present disclosure describe systems, methods, and structures that scavenge mechanical energy to provide electrical energy to a wearable, where the mechanical energy is scavenged by a bending-strain-based transducer that includes a non-resonant energy harvester. By employing a non-resonant energy harvester that operates in bending mode, more electrical energy can be generated that possible with prior-art energy harvesters. In some embodiments the bending-strain-based transducer also includes a sensor and/or a haptic device. Some transducers in accordance with the present disclosure comprise a piezoelectric layer comprising a low-K piezoelectric material, such as aluminum nitride, which enables generation of higher voltage and power/energy output and/or a thinner transducer. As a result, transducers in accordance with the present disclosure can be included in wearables for which large transducer thickness would be problematic, such as sole members (e.g., shoe insoles, midsoles or outsoles), garments, bras, handbags, backpacks, and the like.