In this paper we present a small, credit-card sized, and low-cost electromagnetic energy harvester that couples energy from one conductor of an overhead power distribution line. We use a rectangular coil, placed near the power line without encircling it, to extract electrical power from the time-varying magnetic field. The addition of a U-shaped electrical steel sheet (a high-permeability material typically used in transformers) near the coil significantly increases the magnetic flux through the coil and consequently raises the output power. Experiments have shown that the harvester with an optimal load resistance obtains 230 mW (AC) when the power-line conductor current is 50 A(rms). The energy harvester is able to power a wireless gas sensor board having a carbon monoxide and an ozone sensors at 10 A(rms).

This paper reports the manufacturing and testing via pulsed discharging of printed secondary Zn-MnO2 batteries with ionic liquid gel polymer electrolyte (GPE) for IoT and wearable devices. Printed cells under constant current discharge conditions demonstrated average DC internal resistances of 175-225 Ω/cm2. Printed cells under pulsed discharge current demonstrated decreasing internal resistances with increasing cycle number, reaching an average plateau of 125 Ω/cm2 after 50 cycles and remaining beyond 650 cycles. This work improves upon manufacturing methods reported at PowerMEMS 2015 and investigates system-level compatibility with IoT and wearable devices.

Portable power management systems must optimise power interfacing, storage and routing, to meet application specific functionality requirements. Two key aspects are reliability and efficiency. For reliable operation, it is required that powering on/off the system must occur in a planned manner. For efficient operation, it is desired that the system is powered for an optimal amount of time. maximizing its useful operational outcome per unit of energy consumed. This can be achieved by optimizing energy usage based on the anticipated energy income and power demand of duty-cycled power consumers. Both battery and supercapacitor storage can be employed to meet energy and power density demand, on both sides, and to enable fast transition from cold-starting to active power management. A simplified model is used to calculate the reliability of a simple solar-powered microsystem. The modelling of dynamically configurable interfacing and storage may enable a new generation of power management, providing reliable power from irregular and small energy sources.

In this paper, the possibility of using the static charge that accumulates on aircraft during flight as a source to power monitoring sensors is examined. The assessed methods include using a pair of materials with different air-flow charging rates, contact discharging of the fuselage to neutral metallic bodies, charge motion induction by the fuselage field and inductive harvesting of fuselage-to-air corona discharges at static discharge wicks. The installation and potential advantages of each method are discussed. The feasibility of directly charging a storage capacitor from accumulated static charge is studied experimentally, demonstrating a voltage of 25V on a 25nF capacitor.

We demonstrate a wireless sensor node (WSN) that operates purely on harvested ambient indoor light energy and regulates its duty cycle via voltage-triggered sensing and transmission. The extremely low-power light found in indoor environments can be considered at first sight as unsuitable for high-power load demands characteristic of radios [1], but by leveraging spectrum-tailored solar cells, trickle charging a high-power energy reservoir, and implementing triggered duty cycling, we show that these power demands can be consistently met. All energy harvesting and storage components are fabricated in our labs.

This paper reports an analysis of thermoelectric generator design for dynamic thermoelectric harvesting. In such devices, the available energy for a given temperature cycle is finite and determined by the heat storage unit capacity. It is shown by simulation and experimentally that specific thermoelectric generator designs can increase the energy output, by optimizing the balance between heat leakage and dynamic response delay. A 3D printed, doublewall heat storage unit is developed for the experiments. Output energy of 30 J from 7.5 gr of phase change material, from a temperature cycle between ± 22 °C is demonstrated, enough to supply typical duty-cycled wireless sensor platforms. These results may serve as guidelines for the design and fabrication of dynamic thermoelectric harvesters for applications involving environments with moderate temperature fluctuations.

This paper answers the often asked, and until now inadequately answered, question of which MEMS compatible transducer type achieves the best power density in an energy harvesting system. This question is usually poorly answered because of the number of variables which must be taken into account and the multi-domain nature of the modelling and optimisation. The work here includes models of the mechanics, transducer and the power processing circuits (e.g. rectification and battery management) which in turn include detailed semiconductor models. It is shown that electrostatic harvesters perform better than piezoelectric harvesters at low accelerations, due to lower energy losses, and the reverse is generally true at high accelerations. At very high accelerations using MEMS-scale devices the dielectric breakdown limit in piezoelectric energy harvesters severely decreases their performance thus electrostatics are again preferred. Using the insights gained in this comparison, the optimal transduction mechanism can be chosen as a function of harvesting operating frequency, acceleration and device size.

Motion energy harvesting is a sought after alternative to battery powering for implanted and body worn devices. However, the lack of electricity generation at rest is a major concern. This paper describes a previously presented piezoelectric rotational motion harvester, and presents a mechanism for wireless and external actuation of the main rotor of the device through a magnetic reluctance coupling. With this approach, an internal battery or super-capacitor could be recharged during prolonged periods of inactivity. An improved experimental setup uses a stepper motor to accurately prescribe even high actuation frequencies. A single stack and diametrically opposed dual stacks of driving magnets are investigated. It is demonstrated that adding the additional magnet stack is detrimental to the system performance. Furthermore, the system was tested in a horizontal and a gravity-independent vertical arrangement. Power can successfully be generated regardless of orientation. The maximal separation between driving magnets and harvester reached 20 millimeters. Lastly, the device can operate even under misalignment, and the optimal driving frequency is 25 Hertz, at which over 100 microwatts of power were generated for a device with a functional volume of 1.85 cubic centimeters.

We present a novel way of fabricating circular TEGs using previously developed dispenser printing methods. Dispenser printing provides advantages in low cost and scalable fabrication of high aspect ratio devices in unique patterns. This work presents the synthesis of composite thermoelectric materials optimized for low temperature applications. We also demonstrate device fabrication techniques for high-density arrays of high-aspect ratio circular TEGs wrapped around the pipe for powering condition-monitoring sensors. The printable thermoelectric materials are composed of mechanically alloyed (MA) n-type Bi2Te3 and MA p-type Bi0.5Sb1.5Te3 powders individually dispersed in epoxy polymer resins. The thermoelectric inks were then dispenser printed onto various substrates. A 10 couple circular TEG prototype was fabricated on a flexible printed circuit board. The prototype device produced a power output of 19.5 mu W at a closed circuit voltage of 64mV and a current of 0.30mA for a 50 degrees C temperature difference.

In this paper we investigate the use of RF signals to measure dielectric loss and the change of permittivity of an energized cable's insulation. One common degradation mechanism is growth of water trees in the presence of water. We present theoretical analysis of a novel on-line water tree detection technique based on using RF TEM wave propagation via test points on an elbow. Our method is based on injecting a high frequency RF signal into an energized cable at different points of the line voltage values and measure the nonlinearity of permittivity and dielectric loss.

This paper focuses on a renewable power source for wireless sensor nodes via energy scavenging using thin film piezoelectrics. The novelty of this research is the growth of epitaxial PZT on a Si platform. The films were grown with good consistency using pulsed laser deposition. Using the optimized piezoelectric film properties, an analytical model was generated to predict the output power for a single cantilever, 5.5 nW/beam. Further, if arrays of the cantilevers were packed into a cubic centimeter, the output power would be 80-200 mu W cm(-3). A microfabrication technique was developed to manufacture the cantilevers using standard low-temperature procedures. As the devices demonstrated a significant residual stress upon release, an analytical model was created to predict the residual stress in the films from the high-temperature growth step. A neutral argon bombardment technique was then established to compensate for these stresses and to develop a planar usable device. The initial device fabrication was successful and testing was done to determine resonant frequency, quality factor and output power. The experimental resonant frequency response compared well with what was determined by the model, but the quality factor was 95, which was lower than expected. The output power per cantilever was 24.5 pW over a 510 M Omega load operating over an input vibration of 10 m s(-2) and at resonant frequency (976 Hz).

Wireless manufacturing (WM) has emerged as a next-generation advanced manufacturing technology (AMT). WM relies substantially on wireless devices such as RFID (radio frequency identification) or Auto ID (automatic identification) sensors, and wireless information/communication networks such as Wi–Fi for the collection and synchronisation of manufacturing field data. This paper discusses the recent developments in RFID-based WM solutions. The study is conducted by examining related whitepapers, case reports and research articles available in the literature, and by reflecting on the insights recently experienced in developing prototype solutions. Typical motivations are presented to highlight why and how manufacturers can benefit from applying WM solutions in addressing shop-floor challenges and facilitating contemporary manufacturing strategies. Representative WM manufacturing applications and potentials are presented in the areas of product assembly, part fabrication, just-in-time (JIT), mass customisation, manufacturing asset management and maintenance, and product lifecycle management. Different schemes are discussed for deploying smart objects in manufacturing environments in order to achieve real-time traceability and visibility while minimising the total cost. Key issues are discussed for further research.

A novel super ink jet printing (SIJP) system was used to fabricate 3D zinc–silver microbatteries directly on a substrate. The SIJP provides a simple and flexible method to deposit interesting 2D and 3D structures of varying morphologies without the waste and large energy inputs typical of standard microfabrication technologies. The system was used to print pairs of silver electrodes with arrays of pillars on glass substrates, and in the presence of an electrolyte, the battery self-assembled during the first charge. Using an aqueous electrolyte solution of KOH with dissolved ZnO, the SIJP printed structures showed similar electrochemical behavior to batteries composed of silver foil electrodes. For a sparse array of pillars (∼2.5% footprint area of each electrode pad occupied by pillars), a capacity increase of 60% was achieved in comparison with a cell with planar electrodes.

This paper presents a novel prototype MEMS sensor for alternating current designed for monitoring electricity end-use in residential and commercial environments. This new current sensor design is comprised of a piezoelectric MEMS cantilever with a permanent magnet mounted on the cantilever's free end. When placed near a wire carrying AC current, the magnet is driven sinusoidally, producing a voltage in the cantilever proportional to the current being measured. Analytical models were developed to predict the applicable magnetic forces and piezoelectric voltage output in order to guide the design of a sensor prototype. This paper also details the fabrication process for this sensor design. Released piezoelectric MEMS cantilevers have been fabricated using a four-mask process and aluminum nitride as the active piezoelectric material. Dispenser-printed microscale composite permanent magnets have been integrated, resulting in the first MEMS-scale prototypes of this current sensor design.

In this paper, trends from the last 10 years of inertial micro-generator literature are investigated and it is shown that, although current generator designs are still operating well below their maximum power, there has been a significant improvement with time. Whilst no clear conclusions could be drawn from reported fabricated devices with respect to preferred transducer technology, this paper presents operating charts for inertial micro-generators which identify optimal operating modes for different frequencies and normalized generator sizes, and allows comparison of the different transduction mechanisms as these parameters vary. It is shown that piezoelectric generators have a wider operating range at low frequency than electromagnetic generators, but as generator dimensions increase, the frequency to which piezoelectric transducers outperform electromagnetic transducers decreases.

Vibrational energy scavenging using piezoelectric material is a viable method to provide sufficient energy for low-power wireless sensor networks. The applications for such devices in hospital settings as well as in vivo are abundant. Current devices are limited by both their design and material selection. This paper will address optimizing the design of microscale devices by showing how the device strains under input vibrations are directly proportional to its power output, and by proposing alternate designs which increase the strain distribution over more of the device volume. Finite element modeling (ANSYS®) was used to determine the strain distribution in a cantilever, modified cantilever, trapezoid, and spiral shaped piezoelectric microscale energy scavenging system. The increase in strain under uniform acceleration was determined to be 0, 29.2, 37.8, and 87.0%, respectively, over that of a simple cantilever.

We present new considerations in the design of a MEMS passive, proximity-based electric current sensor for residential and commercial AC electric loads such as appliances and office equipment. The sensor device consists of a permanent magnet mounted to the end of a piezoelectric cantilever. The magnet couples to the alternating magnetic field surrounding an electric power cord, forcing the cantilever sinusoidally. Piezoelectric coupling produces a sinusoidal voltage proportional to the current in the power cord. This design requires no external power source and remains electrically isolated from the current carrier. Models predicting sensor behavior are presented and compared to experimental data. Meso-scale prototypes show sensitivites of 74 mV/A, while simulations suggest MEMS-scale devices will have sensitivities of 2-3 mV/A.

Aluminium production cells, Hall-Héroult ‘potlines’, are inefficient and inadequately outfitted with sensors, mostly due to safety concerns with sensor wires between pots, possible interference with existing hardware, high installation costs, and the lack of an easily accessible, maintenance-free, continuous power source for the sensors. A tested solution to accurately measure various process parameters via wireless sensing technology, using either the cell's exhaust heat or steel shell as a thermoelectric power source is presented. Early experiments at Eastalco indicated that the motes, with a few modifications, will be able to operate reliably under industrial conditions, successfully transmitting radio packets through the plants' strong magnetic fields at distances of over 30 m. This article describes the successful testing of wireless measurements of cell parameters, discusses the energy-scavenging thermoelectric power sources and their electronics, and describes the future plans. The authors work is being carried out in conjunction with Alcoa in hopes of improving cell efficiency through better instrumentation.

In this paper, the trends from the last 10 years of inertial micro-generator literature are investigated and it is shown that, although current generator designs are still operating well below their maximum power, there has been significant improvement with time. Whilst no clear conclusions could be drawn from reported fabricated devices with respect to preferred transducer technology, this paper presents operating charts for inertial micro-generators which identify optimal operating modes for different frequencies and normalized generator sizes, and allows comparison of the different transduction mechanisms as these parameters vary. It is shown that piezoelectric generators have a wider operating range at low frequency than electromagnetic generators, but as generator dimensions increase, the frequency to which piezoelectric transducers outperform electromagnetic transducers decreases.

Sculptured surfaces are relatively dicult to machine due to their complex geometry. Sculptured surface machining primarily has two stages, the rst being roughing and the other being nishing. The current work focuses on generating tool paths for the