•Technologies to harvest electrical energy from wind have vast potentials.•A compact harvester based on flow-induced-vibration was considered.•Four distinct operating modes were tested and analyzed on a prototype.•The harvester exhibited wide wind speed range.In this study, a piezoelectric wind energy harvester was demonstrated, which aimed at addressing the limitations of the existing approaches including single-directional operation and narrow working wind speed range. In the harvester, an arc-shaped elastic beam, instead of conventional thin cantilever beams, was adopted to extract wind energy. Benefiting from the beam’s characteristics of arc-shaped structure and elasticity, the harvester is capable of scavenging wind energy without any extra accessory and responding to multi-directional wind excitations. An analytical model was established to investigate the effects of wind direction and structural parameters on the electrical output. In test, the harvester worked efficiently with wind coming from four directions in a speed range of 2–17 m/s and produced a maximum open-circuit voltage up to 34 V. When connected to an external load of 15 kΩ, the harvester showed a peak output power of 1.73 mW at 17 m/s. In addition, 18 serial-connected commercial light-emitting diodes (LEDs) were lit up simultaneously at the wind speed of 10.5 m/s, which confirmed the practicability of the harvester.

•We propose a novel vibration energy harvester using a magnetoelectric (ME) transducer.•The harvester is applicable in arbitrary in-plane motion directions and over a wide vibration frequency.•A circular cross-section cantilever rod is adopted to extract the ambient vibration in arbitrary motion directions.•The magnetic interactions lead to the nonlinear oscillation of the rod with increased frequency bandwidth.This paper presents a design for a novel vibration energy harvester using a magnetoelectric (ME) transducer, which is efficiently applicable in two-dimensional (2D) motion and over a range of vibration frequencies. This harvester adopts a circular cross-section cantilever rod to extract the ambient vibration energy because of its ability to host accelerations in arbitrary motion directions. Moreover, the magnetic interactions between the magnets and the ME transducer will lead to the nonlinear oscillation of the rod with increased frequency bandwidth. The influences of the nonlinear vibration factor and magnetic field distribution on the electrical output and bandwidth of the harvester are investigated to achieve optimal vibration energy harvesting performances. The experimental results showed that, the harvester was sensitive to the vibration with arbitrary in-plane directions. With an acceleration of 0.6 g (where g = 9.8 ms−2), it had the working bandwidths of 4.2 Hz, 2.6 Hz, 2.3 Hz, 2.5 Hz and 3.2 Hz, and the output powers of 0.6 mW, 0.49 mW, 0.33 mW, 0.5 mW and 0.56 mW at the in-plane excitation angles of−90°, −45°, 0°, 45° and 90°, respectively.

A magnetoelectric (ME) vibration energy harvester has been designed to scavenge sufficient energy from ambient vibration with arbitrary motion directions in a plane and over a range of frequencies. In the harvester, a circular-cross-section cantilever rod is adopted to extract the vibration energy due to its ability to host accelerations in arbitrary in-plane motion directions. The magnetic coupling between the magnet and the ME transducer results in nonlinear oscillation of the cantilever rod with increased frequency bandwidth. To achieve optimal vibration energy harvesting performance, the effects of the nonlinear vibration and the harvester parameters including the magnetic circuit and the separation distance on the electrical output and the␣working bandwidth are analyzed. The experimental results show that the harvester can scavenge vibration energy in arbitrary in-plane directions, exhibiting a bandwidth of 4.0 Hz and maximum power of 0.22 mW at acceleration of 0.6g (with g = 9.8 m s−2).

Magnetoelectric (ME) transducers were originally intended for magnetic field sensors but have recently been used in vibration energy harvesting. In order for vibration energy harvesters to be effective over a range of vibration frequencies, recently many technologies have been investigated to broaden the frequency range of the harvesters using piezoelectric, electromagnetic and electrostatic transductions, but few have been studied that use ME transducers. This paper presents a new broadband vibration energy harvester using ME transducer, which takes advantage of multi-cantilever beams and nonlinear behavior of the magnetic force to expand the working bandwidth in ambient low frequency vibration. And a theoretical model is developed to analyze the non-sinusoidal proof mass motion and the electrical-output performances of the harvester. The experimental results show that the harvester has a bandwidth of 5.4 Hz and power density of 0.2–0.56 mW/cm3 over the entire frequency range under an acceleration of 0.2 g (with g = 9.8 ms−2).

•A lightweight, cost-effective and scalable strain sensor with excellent performance is developed by utilizing the micro-cracked metal thin film by combining the overlap modal with tunnel effect of the adjacent cracks;•Detection of tiny strain of human non-joints, physiological pulse wave, canthus motion and any biological associated skin deformation is demonstrated;•Mapping of strain distribution and anti-interference voice recognition system using this sensor pave the way to practical applications in smart sensor system and wearable electronics.The poor detecting limit and attenuated sensitivity to tiny strain of a strain sensor retard their development toward practical applications ranging from wearable electronics, human healthcare monitoring to smart sensing system. Here, a strain sensor with high sensitivity to tiny strain, high flexibility, fast response and good stability is developed utilizing the micro-cracked metal thin film based on a novel working principle of combining the overlap mode with tunnel effect of the adjacent cracks. Monitoring of human motions and physiological signals as well as anti-interference voice recognition based on the sensor is demonstrated, showing its potential applications in wearable electronics, human healthcare monitoring and smart sensing system.Large-scale strain sensor with attributes of high sensitivity, highly flexibility, fast response and good stability is developed utilizing the micro-cracked metal thin film to satisfy practical applications in detection of human non-joint areas tiny strain and non-interference voice recognition, representing an important step toward design and applications of the strain sensor.

•Technologies to harvest electrical energy from wind have vast potentials.•A compact harvester based on flow-induced-vibration was considered.•Four distinct operating modes were tested and analyzed on a prototype.•The harvester exhibited wide wind speed range.In this study, a piezoelectric wind energy harvester was demonstrated, which aimed at addressing the limitations of the existing approaches including single-directional operation and narrow working wind speed range. In the harvester, an arc-shaped elastic beam, instead of conventional thin cantilever beams, was adopted to extract wind energy. Benefiting from the beam’s characteristics of arc-shaped structure and elasticity, the harvester is capable of scavenging wind energy without any extra accessory and responding to multi-directional wind excitations. An analytical model was established to investigate the effects of wind direction and structural parameters on the electrical output. In test, the harvester worked efficiently with wind coming from four directions in a speed range of 2–17 m/s and produced a maximum open-circuit voltage up to 34 V. When connected to an external load of 15  kΩ, the harvester showed a peak output power of 1.73 mW at 17 m/s. In addition, 18 serial-connected commercial light-emitting diodes (LEDs) were lit up simultaneously at the wind speed of 10.5 m/s, which confirmed the practicability of the harvester.