The following relates generally to measuring a patients O.sub.2 level with a mote implanted in the patient's tissue. For example, a mote implanted in a patients tissue may be powered by ultrasound (US) signals generated by an ultrasound interrogator that is external to the patient. Components on the mote may be duty cycled off to advantageously decrease power consumption. A luminescence sensor on the mote may be used to measure the O.sub.2 level, and the luminescence sensor may be optically isolated from the patients tissue by an opaque material such as black silicon.

Described herein is an energy harvesting system comprising a transducer and a processor. The transducer generates an electric signal from ambient energy. The processor is configured to process the electric signal to perform pattern recognition of the electric signal so as to determine and output a characteristic of a source of the ambient energy. The pattern recognition comprises statistical analysis and frequency domain analysis.

Disclosed is a self-powered vibration damper based on piezoelectricity and a control method. The damper comprises a loading platform, an energy collecting mechanism, a curved leaf spring, a vibration control mechanism and a substrate all connected in sequence, the circuit system comprises a rectifier circuit, a DC-DC voltage conversion circuit, an energy storage circuit, a control circuit and a charging battery, a first piezoelectric stack is connected with the input end of the rectifier circuit, the output end of the rectifier circuit is connected with the input end of the DC-DC voltage conversion circuit, the output end of the DC-DC voltage conversion circuit is connected with the input ends of the energy storage circuit and the charging battery, the output end of the energy storage circuit is connected with the input end of the control circuit, the output end of the control circuit is connected with the second piezoelectric stack.

In certain examples, methods and semiconductor structures are directed to operation of a piezoelectric-based device (e.g., a DC-DC converter) and such operation may involve selectively switching inputs of the piezoelectric-based device at a modulation frequency and, in response, decoupling of the modulation frequency from output power delivered by the piezoelectric-based device. In some examples, the inputs of the piezoelectric-based device are selectively switched to cause decoupling the modulation frequency from output power delivered by the piezoelectric-based device and/or cause operation of the piezoelectric-based device without spurious mode operation.

A smart ring is configured harvest mechanical energy using piezoelectricity. The smart ring includes a ring-shaped housing, a power source disposed within the ring-shaped housing, and a charging circuit. The charging circuit includes a piezoelectric harvesting element, and is configured to charge the power source when user motion causes a mechanical deformation in the piezoelectric harvesting element. The smart ring further includes a component, disposed within the ring-shaped housing and configured to draw energy from the power source, and further configured to perform at least one of: i) sense a physical phenomenon external to the ring-shaped housing, ii) send communication signals to a communication device external to the ring-shaped housing, or iii) implement a user interface.

A smart ring is configured harvest mechanical energy using piezoelectricity. The smart ring includes a ring-shaped housing, a power source disposed within the ring-shaped housing, and a charging circuit. The charging circuit includes a piezoelectric harvesting element, and is configured to charge the power source when user motion causes a mechanical deformation in the piezoelectric harvesting element. The smart ring further includes a component, disposed within the ring-shaped housing and configured to draw energy from the power source, and further configured to perform at least one of: i) sense a physical phenomenon external to the ring-shaped housing, ii) send communication signals to a communication device external to the ring-shaped housing, or iii) implement a user interface.

An energy harvester (100) includes: an inner band (110); an outer band (120) arranged to surround the inner band (110), wherein the inner band (110) is coupled to the outer band (120) at a fixed end (20) and the inner band (110) is spaced from the outer band (120) at a free end (30); and an energy generator (150) arranged to generate electric energy through relative movement between the inner band (110) and the outer band (120) at the free end (30). Also disclosed is a wearable device (10) including: a wearable strap formed by the inner band (110) and the outer band (120) of the energy harvester (100), and a mass (130) arranged to receive at least a portion of the wearable device (10).

An energy harvesting module includes a pendular unit with piezoelectric transducer elastically deformable in bending between a clamped end and a free end coupled to an inertial mass. The piezoelectric transducer includes two coplanar piezoelectric beams arranged side-by-side on either side of a central axis of the transducer, each of the piezoelectric beams including adjacent external and internal arms, arranged side-by-side and formed single-piece. The external arm of each beam has a clamped proximal end and a free distal end, and the internal arm of each beam has a free proximal end supporting the inertial mass, and a free distal end connected to the distal end of the adjacent external arm by a common junction.

A module includes a pendular unit with piezoelectric transducer elastically deformable in bending with a clamped end and a free end coupled to an inertial mass. The piezoelectric transducer includes at least one piezoelectric beam configured into two adjacent arms formed single-piece, with an external arm and an internal arm arranged side-by-side. The external arm has a clamped proximal end and a free distal end, and the internal arm has a free proximal end supporting the inertial mass, and a free distal end connected to the distal end of the adjacent external arm. An annular mount surrounds the beam at its proximal end and includes the clamp to which is fastened the proximal end of the external arm. The mount includes, in a central region in the vicinity of the clamp, a cavity inside which the inertial mass carried by the free proximal end of the internal arm can oscillate.

An energy harvester includes an elongated tubular casing extending around a longitudinal axis between opposed first and second ends. A body is arranged in the casing. A helical electrical winding is wound around the longitudinal axis. The body is arranged to move along the longitudinal axis with alternate motion away from the first end towards the second end and away from the second end towards the first end. As a result of this alternate motion, an electromotive force is produced in the at least one helical electrical winding. Furthermore, at least one of the first and second ends includes a piezoelectric transducer that is configured to co-operate in a kinetic energy transfer relationship with the at least one body to generate an electric voltage as a result of the at least one body reaching, in the alternate motion, an end-of-travel position towards the piezoelectric transducer.