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This paper aims to present the design of a cantilever beam with various kinds of geometries for application in energy harvesting devices with a view to enhance the harvested power. The cantilever beams in rectangular, triangular and trapezoidal geometries are simulated, designed and evaluated experimentally. A power conditioning circuit is designed and fabricated for rectification and regulation.

The analytical model based on Euler–Bernoulli beam theory is analyzed for various cantilever geometries. The aluminum beam with Lead Zirconate Titanate (PZT) 5H strip is used for performing frequency, displacement, strain distribution, stress and potential analysis. A comparative analysis is done based on the estimated performance of the cantilevers with different topologies of 4,500 mm³ volume.

The analysis shows the trapezoidal cantilever yielding a maximum voltage of 66.13 V at 30 Hz. It exhibits maximum power density of 171.29 W/mm³ at optimal resistive load of 330 kΩ. The generated power of 770.8 µW is used to power up a C-mote wireless sensor network.

This study provides a complete structural analysis and implementation of the cantilever for energy harvesting application, integration of power conditioning circuit with the energy harvester and evaluation of the designed cantilevers under various performance metrics.

The purpose of this paper is to fabricate an ethanol sensor which has bio-friendly and eco-friendly properties compared to the commercially available ethanol sensors.

This paper describes the construction of a highly sensitive ethanol sensor with low ppm level detection at room temperature by integrating three techniques. The first deals with the formation of organic/inorganic p-n heterojunction. Second, tuning of structural parameters such as length, diameter and density of Zinc Oxide (ZnO) nanostructure was achieved through introduction of the Fe dopant into a pure ZnO seed layer. Furthermore, ultra-violet (UV) light photoactivation approach was used for enhancing the sensing performance of the fabricated sensors. Four different sensors were fabricated by combing the above approaches. The structural, morphological, optical and material compositions were characterized using different characterization techniques. Sensing behavior of the fabricated sensors toward ethanol was experimented at room temperature with and without UV illumination combined with stability studies. It was observed that all the fabricated sensors showed enhanced sensing performance for 10 ppm of ethanol. In specific, FNZ (Fe-doped ZnO seeded Ni-doped Zn nanorods) sensor exhibited a higher response at 2.2 and 13.5 s for 5 ppm and 100 ppm of ethanol with UV light illumination at room temperature, respectively. The photoactivated FNZ sensor showed quick response and speedy recovery at 18 and 30 s, respectively, for 100 ppm ethanol.

In this study, the authors have experimentally analyzed the effect of Fe (in ZnO seed layer and ZnO NRs) and Ni (in ZnO NRs) dopants in the room temperature sensing performance (with and without UV light) of the fabricated ethanol sensors. Important sensing parameters like sensitivity, recovery and response time of all the fabricated sensors are reported.

The Fe doped ZnO seeded Ni doped Zn nanorods (FNZ sample) showed a higher response at 2.2 s and 13.5 s for very low 5 ppm and 10 ppm of ethanol at room temperature under UV light illumination when compared to the other fabricated sensors in this paper. Similarly, this sensor also had quick response (18 s) and speedy recovery (30 s) for 100 ppm ethanol.

The purpose of this paper is to present the design of a piezoelectric vibration energy generator with a power conditioning circuit to power a wireless sensor node. Frequency and voltage characterization of the piezoelectric energy harvester is performed. A single-stage AC–DC power converter that integrates the rectification and boosting circuit is designed, simulated and implemented in hardware.

The designed power conditioning circuit incorporates bridgeless boost rectification, a lithium ion battery as an energy storage unit and voltage regulation to extract maximum power from PZT-5H and to attain higher efficiency. The sensor node is modelled in active and sleep states on the basis of the power consumption. Dynamic modelling of the lithium ion battery with its state of charging and discharging is analysed.

The test result shows that the energy harvester produces a maximum power of 65.9 mW at the resonant frequency of 21.4 Hz. The designed circuit will operate even at a minimum input voltage of 0.5 V. The output from the harvester is rectified, boosted to a 7-V DC output and regulated to 3.3 V to the power C_Mote wireless sensor node. The conversion efficiency of the circuit is improved to 70.03 per cent with a reduced loss of 19.76 mW.

The performance of the energy harvester and the single-stage power conditioning circuit is analysed. Further, the design and implementation of the proposed circuit lead to an improved conversion efficiency of 70.03 per cent with a reduced loss of 19.76 mW. The vibration energy harvester is integrated with a power conditioning circuit to power a wireless sensor node C_Mote. The piezoelectric vibration energy harvester is implemented in real time to power C_Mote.