Energy harvesting has grown from long-established concepts into devices for powering ubiquitously deployed sensor networks and mobile electronics. Systems can scavenge power from human activity or derive limited energy from ambient heat, light, radio, or vibrations. Ongoing power management developments enable battery-powered electronics to live longer. Such advances include dynamic optimization of voltage and clock rate, hybrid analog-digital designs, and clever wake-up procedures that keep the electronics mostly inactive. Exploiting renewable energy resources in the device's environment, however, offers a power source limited by the device's physical survival rather than an adjunct energy store. Energy harvesting's true legacy dates to the water wheel and windmill, and credible approaches that scavenge energy from waste heat or vibration have been around for many decades. Nonetheless, the field has encountered renewed interest as low-power electronics, wireless standards, and miniaturization conspire to populate the world with sensor networks and mobile devices. This article presents a whirlwind survey through energy harvesting, spanning historic and current developments.

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Energy scavenging for mobile and wireless electronics

The field of power harvesting has experienced significant growth over the past few years due to the ever-increasing desire to produce portable and wireless electronics with extended lifespans. Current portable and wireless devices must be designed to include electrochemical batteries as the power source. The use of batteries can be troublesome due to their limited lifespan, thus necessitating their periodic replacement. In the case of wireless sensors that are to be placed in remote locations, the sensor must be easily accessible or of a disposable nature to allow the device to function over extended periods of time. Energy scavenging devices are designed to capture the ambient energy surrounding the electronics and convert it into usable electrical energy. The concept of power harvesting works towards developing self-powered devices that do not require replaceable power supplies. A number of sources of harvestable ambient energy exist, including waste heat, vibration, electromagnetic waves, wind, flowing water, and solar energy. While each of these sources of energy can be effectively used to power remote sensors, the structural and biological communities have placed an emphasis on scavenging vibrational energy with piezoelectric materials. This article will review recent literature in the field of power harvesting and present the current state of power harvesting in its drive to create completely self-powered devices.

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A review of power harvesting using piezoelectric materials (2003–2006)

A surgical stapling device particularly suited for endoscopic procedures is described The device includes a handle assembly and an elongated body extending distally from the handle assembly The distal end of the elongated body is adapted to engage a disposable loading unit A control rod having a proximal end operatively connected to the handle assembly includes a distal end extending through the elongated body A control rod locking member is provided to prevent movement of the control rod until the disposable loading unit is fully secured to the elongated body of the stapling device

Surgical Stapling Apparatus

Energy harvesting generators are attractive as inexhaustible replacements for batteries in low-power wireless electronic devices and have received increasing research interest in recent years. Ambient motion is one of the main sources of energy for harvesting, and a wide range of motion-powered energy harvesters have been proposed or demonstrated, particularly at the microscale. This paper reviews the principles and state-of-art in motion-driven miniature energy harvesters and discusses trends, suitable applications, and possible future developments.

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Energy Harvesting From Human and Machine Motion for Wireless Electronic Devices

A surgical stapling instrument (1) comprises a body portion (2, 3), a handle (4) and a staple fastening assembly (8). The staple fastening assembly (8) includes a curved cartridge (10), which comprises at least one curved open row of staples, and a curved anvil (22), which is adapted to cooperate with the cartridge (10) for forming the ends of the staples exiting from the cartridge (10). The staple fastening assembly (8) is adapted to allow unobstructed access towards the concave inner faces of the cartridge (10) and the anvil (22). The cartridge (10) can be moved towards the anvil (22) from a spaced position for positioning tissue therebetween to a closed position for clamping the tissue. Preferably, a knife is contained within the cartridge (10) and is positioned such that there is at least one row of staples on at least one side of the knife.

Surgical stapling instrument

An electronic system includes a reader and a remotely powered and remotely interrogated sensor transponder. The sensor transponder includes a coil or an antenna, a switched reactance circuit, a processor, and a sensor. The sensor transponder receives power radiated from the reader to the coil or antenna. The sensor uses the power for sensing. The sensor transponder is capable of processing sensor data in the processor and transmitting the sensor data to the reader using the switched reactance circuit. In one embodiment, the receiver coil or antenna is part of a resonant tank circuit which includes an impedance matching circuit. The impedance matching circuit is connected to the receiver coil or antenna to provide greater current to the sensor or other power-using device than would be available to the sensor or other power-using device if the sensor or other power-using device were connected between the first and second end. The impedance matching circuit can be two or more taps to the coil or antenna.

Remotely powered and remotely interrogated wireless digital sensor telemetry system

A device for powering a load from an ambient source of energy is provided. The device includes an energy harvesting device for harvesting energy from the ambient source of energy wherein the rate energy is harvested from the ambient source of energy is below that required for directly powering the load. A storage device is connected to the energy harvesting device. The storage device receives electrical energy from the energy harvesting device and is for storing the electrical energy. A controller is connected to the storage device for monitoring the amount of electrical energy stored in the storage device and for switchably connecting the storage device to the load when the stored energy exceeds a first threshold. The system can be used for powering a sensor and for transmitting sensor data, such as tire pressure.

Energy harvesting for wireless sensor operation and data transmission

A device for monitoring a rotating shaft is provided. The device measures strain in the shaft and provides angular velocity and torque in the shaft. The device includes a sensor, sensor conditioning circuitry, a microprocessor, and a transmitter, all located on a rotating shaft. The device obtains power by harvesting mechanical energy of the rotating shaft itself. Coils are provided rotating with the shaft and permanent magnets are mounted adjacent the rotating shaft so electrical energy is induced in the coils as they rotate through the magnetic field of the permanent magnets. A battery or capacitor is connected to the coils for storing energy. A microprocessor is connected to the sensors, the storage device, and the transmitter for managing power consumption and for monitoring the amount of electrical energy stored in the storage device and for switchably connecting the storage device to the transmitter when the stored energy exceeds a threshold.

Shaft mounted energy harvesting for wireless sensor operation and data transmission

A sensing device includes an RFID chip and a differential variable reluctance transducer (DVRT) sensor that can be read remotely with electromagnetic power provided to the device from a remote reader. The ac signal provided to the device by inductance is used for powering the RFID chip and exciting the sensor. Data read from the sensor can also be transmitted back to the reader using the power provided by the reader. The sensor circuit uses a lower amount of current than the RFID chip, so it does not contribute appreciably to device power requirements.

Micropower peak strain detection system for remote interrogation

A system includes a moveable body and a first device for mounting on the movable body. The first device includes an orientation sensor, an inertial position sensor, a first processor, a frequency agile RF transceiver, and a memory device.

Michael J. Hamel

Papers

Remotely powered and remotely interrogated wireless digital sensor telemetry system

Energy harvesting for wireless sensor operation and data transmission

Shaft mounted energy harvesting for wireless sensor operation and data transmission

Micropower peak strain detection system for remote interrogation

Miniaturized wireless inertial sensing system