A sensing unit for use in-body comprises a variable impedance circuit for connection to the distal end of a transmission line and reflecting a carrier signal received from the transmission line. The variable impedance circuit comprises a variable impedance component having an impedance which varies non-linearly with applied voltage, a sensor for generating a voltage in response to a stimulus and a voltage bias system for creating a voltage bias for the variable impedance component. The voltage bias sets the operation point of the variable impedance component, such that the voltage changes from the sensor change the impedance of the variable impedance component non-linearly.

Power generation devices and methods for use with toilets is disclosed. A number of power generation devices are provided that can be used in combination to power various features in a toilet which will be particularly useful for portable toilets that are off the grid. The power generation devices and methods include, for example, using a cell battery inside a toilet water source, a wind turbine, solar panels, and piezoelectricity. The features include, for example, lighting up the toilet with light-emitting diodes (LEDs) to make it easier for users to find the toilet, an audio/video setup for entertainment, and a toilet status light indicator to let the next user know when the toilet paper is out.

The invention relates to a piezoelectric energy harvesting system (10) configured to be installed on a vehicle (1), characterized in that the system (10) comprises: —an inner panel (12); —an outer panel (14) slidably movable relative to the inner panel (12); —at least one deformable piezoelectric element (16) disposed between the inner panel (12) and the outer panel (14), said piezoelectric element (16) being capable of producing electrical power when it is deformed; —a plurality of impact elements (18) fixedly connected to the outer panel (14) and adapted to apply a compression force on the at least one piezoelectric element (16) when the outer panel (14) and the inner panel (12) are close enough to each other, said compression force causing a mechanical deformation of the at least one piezoelectric element (16); —repulsion means (22) adapted to move the outer panel (14) away from the inner panel (12); —an electrical power storage unit (24); —a one-way electrical circuit (26) connecting the at least one piezoelectric element (16) to the electrical power storage unit (24), said one-way electrical circuit (26) being adapted to charge the electrical power storage unit (24) with the electrical power produced by the at least one piezoelectric element (16) while preventing the application of an electrical charge to the at least one piezoelectric element (16) from the electrical power storage unit (24).

An energy harvesting circuit is disclosed and comprises one or more electrical loads that consume direct current (DC) power, a rectifier, and a hybrid acoustic absorber. The rectifier comprises one or more active switching elements that are driven by a gate drive voltage. The hybrid acoustic absorber comprises a diaphragm and a voice coil. The diaphragm is constructed at least in part of a piezoelectric material. The piezoelectric material is configured to generate a diaphragm voltage in response to sound waves deforming the diaphragm. The diaphragm voltage is at least equal to the gate drive voltage to drive the one or more active switching elements of the rectifier. The voice coil is attached to the diaphragm and configured to generate a voice coil voltage that is less than the gate drive voltage of the one or more active switching elements.

A self-powered delineator includes a wind-powered rotatable module; a first piezoelectric energy generator module for generating electrical energy; a second piezoelectric energy generator module for generating electrical energy; and a light-emitter. The wind-powered rotatable module includes one or more first magnets spacedly arranged around a rotation shaft. The first piezoelectric energy generator module includes one or more first piezoelectric elements, and one or more second magnets disposed on the at least one first piezoelectric element. The second piezoelectric energy generator module includes at least one elastic base extending radially from a fixed shaft in a cantilever manner; and at least one second piezoelectric element on the at least one elastic base.

The present application provides a human joint energy harvesting apparatus for capturing the biomechanical energy of a joint to generate electrical energy. The generated electrical energy may provide a real-time power supply to the wearable electronics. The apparatus employs a linear slide rail mechanism and cooperates with the user's first limb and second limb to form a slider-crank mechanism, which converts the rotating motion of the joint into a linear motion of the linear slide rail mechanism. The bending beam converts the linear motion of the linear slide rail mechanism into a bending motion. A piezoelectric film may be bonded to the upper and lower surfaces of the bending beam. During walking, the bending beam is deformed, causing the piezoelectric film to be stretched or compressed to generate electrical energy. To harvest more energy, the bending beam used in the apparatus is designed to be subjected to forced motion and free vibration, and a proof mass is attached to it. The present application also provides a wearable electronic device equipped with the human joint energy harvesting apparatus.

Provided is an apparatus for generating direct current using continuous polarization change of piezoelectric materials. For example, a piezoelectric direct current generator includes a first electrode, a polarized piezoelectric material layer disposed on a first surface of the first electrode, and a second electrode disposed on a surface opposite to the first electrode and coupled to move along the piezoelectric material layer while pressing the piezoelectric material layer.

A piezoelectric energy harvesting device is provided. The piezoelectric energy harvesting device includes a piezoelectric material, which includes an inner surface having a concave shape, and an outer surface having a bottom surface. The piezoelectric energy harvesting device further includes a ball positioned on the inner surface. The bottom surface acts as a ground, the inner surface acts as a positive node, and the inner surface, the outer surface, and the ball are configured so that movement of the ball causes mechanical stress to the piezoelectric material, producing an electrical current.

The present inventors have recognized that an electrical switch for opening doors in buildings, calling elevators, and the like can be improved to require less physical contact, larger activation area, and multiple activation methods, with increased reliability, by utilizing a piezoelectric sensor specifically arranged between rigid, parallel mounting plates in which one of the plates (an inner plate) is rigidly fixed to prevent movement while the other plate (an outer plate) is accessible for receiving physical contact. By rigidly fixing the inner plate, such as by mounting to a wall or bollard, the sensor can react with sensitivity upon an application of less pressure on the outer plate. Such pressure compresses the sensor between the plates to produce an electrical signal. A controller receiving the signal can, in turn, execute to open a door, call an elevator and/or activate a light or sound to provide feedback.

The module comprises a pendular unit with an elastically deformable piezoelectric beam having a clamped end and an opposite, free end, coupled to an inertial mass. The beam produces an oscillating electrical signal collected by electrodes, which is rectified and regulated to output a voltage for charging a battery. The number and configuration of the electrodes (T1, T2, B1, B2, N) carried by the piezoelectric beam define a plurality of pairs of electrodes between which a corresponding plurality of said oscillating signals can be simultaneously collected. A switching matrix, as a function of an input command, selectively switches the plurality of pairs of electrodes between each other according to a plurality of different series (S), parallel (P) and/or series-parallel (SP) configurations, the selected configuration being that which maximizes the power sent to the battery as a function of the voltage level (VBAT) present at the terminals of the latter.