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This study covers a self-powered wireless communication system that is powered using a piezoelectric energy harvester (PEH) in a shoe. The lead-zirconate-titanate (PZT) ceramic of the PEH was coated with UV resin, which (after curing under UV light) allowed it to withstand periodic pressure. The PEH was designed with a simple structure and placed under the sole of a shoe. The durability of the PEH was tested using a pushing tester and its applicability in shoes was examined. With periodic compression of 60 kg, the PEH produced 52 μW of energy at 280 kΩ. The energy generated by the PEH was used to power a wireless transmitter. A step-down converter with an under-voltage lockout function was used to gather enough energy to operate the wireless transmitter. The transmitter can be operated initially after walking 24 steps. After the transmitter has been activated, it can be operated again after 8 steps. Because a control center receives signals from the transmitter, it is possible to check the status of workers who work outside at night or mostly alone, to detect emergencies. [ABSTRACT FROM AUTHOR]

To meet the increasing demand for electric vehicles, this paper presents a novel concept to enhance the energy generation performance of piezoelectric energy harvesters used as charging stations on roads. A lever-type piezoelectric energy harvester with a deformation-guiding mechanism was designed and fabricated to overcome the existing limitations of low electrical output and low durability of piezoelectricity under extremely low road displacement conditions of 1 mm. The proposed harvester achieved a maximum output power of 60.3 mW at a load resistance of 50 kΩ under an input displacement of 1 mm. Thus, the module's electrical performance was significantly higher than that obtained in previous similar studies. The proposed harvester had 467% higher output power than the previously proposed vibration type road energy harvester. For the energy storage test, a 0.08 F supercapacitor was charged up to 5.09 V (1 J) in 170 min. The results prove that the energy generated by the proposed harvester can be potentially used as a power source for electric vehicles on smart roads beyond the power supply of various sensor systems on the road. • A lever-type piezoelectric energy harvester by deformation-guiding mechanism is proposed. • The harvesting module produces 60.3 mW under 1 mm displacement. • A 0.08 F supercapacitor was charged up to 5.09 V (1 J) for 170 min. • This system can be potentially used as a power source for an electric vehicle. [ABSTRACT FROM AUTHOR]

Piezoelectric 0.72 Pb(Zr 0.47 Ti 0.53 )O 3 -0.28 Pb[(Zn 0.45 Ni 0.55 ) 1/3 Nb 2/3 ]O 3 + 0.5 mol% CuO (PNNC) particles were made for use in a composite of flexible energy harvester (FEH) that can convert sustainable mechanical deformation into electrical energy. The PNNC particles with a high transduction coefficient ( d 33  ×  g 33 ) were mixed with polydimethylsiloxane (PDMS) matrix to produce the FEH. The FEH generated maximum output voltage of 55.24 V and current density of 2.76 μA/cm 2 (power density: 554 μW/cm 3 , 3.2 mW) at the resonance frequency of 11 Hz. The energy conversion efficiency of about 20.7% has been achieved. The developed energy harvester is demonstrated in the self-powered wireless sensor node application in which the FEH spontaneously generated stable power under continuous mechanical stress. [ABSTRACT FROM AUTHOR]

The power generated by the designed piezoelectric energy harvester replaces the standby power that is constantly used in sensors and driving circuits in commercial LED shoes; the harvester thus reduces battery consumption. LED shoes incorporating a piezoelectric energy harvester are designed for night workers who work near roads. The piezoelectric energy harvester, composed of a piezoelectric device (PZT ceramic), which is inserted under the insoles of shoes, converts mechanical energy generated by motion of user into electrical energy. The designed harvester has an area of 6 × 4 mm and height of 3 mm (pressed state); it weighs 14 g. Because of its small size and light weight, device is suitable for real workers' shoes. This piezoelectric energy harvester produces 800 μW at a resistive matching point of 400 kΩ; it is used as a sensor to control an LED switching circuit, allowing the LEDs to blink based on user movements. By applying the piezoelectric energy harvester to LED shoes, battery usage time can be doubled compared to LED shoes that are turned on continuously. • Designed piezoelectric energy harvester has an area of 6 × 4 mm and height of 3 mm. • Piezoelectric energy harvester produces 800 μW at a resistive matching point of 400 kΩ. • Harvester works as a sensor to drive an LED switching circuit in LED shoes. • The proposed LED shoes enhance the visibility of night workers in dark areas. • Battery usage time can be doubled compared to LED shoes. [ABSTRACT FROM AUTHOR]