Wearable Shoe-Mounted Piezoelectric Energy Harvester for a Self-Powered Wireless Communication System

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.

Multisite Simultaneous Neural Recording of Motor Pathway in Free-Moving Rats

Neural interfaces typically focus on one or two sites in the motoneuron system simultaneously due to the limitation of the recording technique, which restricts the scope of observation and discovery of this system. Herein, we built a system with various electrodes capable of recording a large spectrum of electrophysiological signals from the cortex, spinal cord, peripheral nerves, and muscles of freely moving animals. The system integrates adjustable microarrays, floating microarrays, and microwires to a commercial connector and cuff electrode on a wireless transmitter. To illustrate the versatility of the system, we investigated its performance for the behavior of rodents during tethered treadmill walking, untethered wheel running, and open field exploration. The results indicate that the system is stable and applicable for multiple behavior conditions and can provide data to support previously inaccessible research of neural injury, rehabilitation, brain-inspired computing, and fundamental neuroscience.

Optimal Wireless Information and Power Transfer Using Deep Q-Network

In this paper, a multiantenna wireless transmitter communicates with an information receiver while radiating RF energy to surrounding energy harvesters. The channel between the transceivers is known to the transmitter, but the channels between the transmitter and the energy harvesters are unknown to the transmitter. By designing its transmit covariance matrix, the transmitter fully charges the energy buffers of all energy harvesters in the shortest amount of time while maintaining the target information rate toward the receiver. At the beginning of each time slot, the transmitter determines the particular beam pattern to transmit with. Throughout the whole charging process, the transmitter does not estimate the energy harvesting channel vectors. Due to the high complexity of the system, we propose a novel deep Q-network algorithm to determine the optimal transmission strategy for complex systems. Simulation results show that deep Q-network is superior to the existing algorithms in terms of the time consumption to fulfill the wireless charging process.

The Analysis and Design of a High Efficiency Piezoelectric Harvesting Floor with Impacting Force Mechanism

In renewable energy technology development, piezoelectric material has electro-mechanical converted capability and the advantages of simple construction and compact size, it has potential development since the environment vibration can be transferred into an electrical energy in daily harvesting applications. To improve the electro-mechanical converted efficiency of a piezoelectric harvester at low-frequency environment, a free vibration type of piezoelectric cantilever harvesting structure was proposed, which can generate a resonant oscillation by releasing an initial deformed displacement, and was uninfluenced from the effects of external environment. To analyze the harvesting behaviors, an equivalent circuit with voltage source was provided, and the parameters in theoretical model can be determined by the dimensions of the piezoelectric unimorph plate and its initial deformation. From the comparison of measurement and simulation, it reveals a significant efficient theoretical model where 8% error occurrence for storage energy was found. Finally, the proposed free-vibration generation method was developed in a piezoelectric harvesting floor design, which can transfer human walking motion into electric energy, and store in an external storage capacitor. From the testing result, one time of footstep motion can cause the charging energy in a 33 μF of storage capacitor achieve to 0.278 mJ, which was larger than the driven power of the wireless transmitter module, and then the wireless transmitter can be driven to send a RF signal without external power supply. Therefore, the designed piezoelectric harvesting floor has potential development to locate the user’s current position, which can provide users with future appropriate service for intelligent building application.

Compact 5G Hairpin Bandpass Filter Using Non-Uniform Transmission Lines Theory

A compact three order 5G low frequency band Hairpin Bandpass Filter (HPBF) is analyzed, designed and fabricated in this paper. The designed filter operates at 5G frequency range (5.975-7.125 GHz). 17.76% compactness in each λ/2 uniform transmission line (UTL) resonator of the filter is achieved by applying Non-Uniform Transmission Lines (NTLs) theory. This compactness will make modern wireless transmitter and receiver designs more compatible. Study on the best reduction size percentage and suitable constraints to design the required NTL resonator is highlighted in this paper. Six samples with different size reductions percentage are fabricated and measured. The simulation is carried out in this study uses High Frequency Structure Simulator (HFSS) software and Computer Simulation Technology (CST) software. The simulated results for UTL HPBF and NTL HPBF with the six cases are verified with measurement. For the best size reduction percentage design, the measured results demonstrated that the 6.55 GHz NTL and UTL HPBF show good impedance matching within the unsilenced 5G frequency band.

Wireless electric energy transmission system and its recording system using PZEM004T and NRF24L01 module

<span id="docs-internal-guid-c15e9fd9-7fff-537c-ddf2-1938aca07829"><span>Electrical energy can not be separated from the name kWh Meter, a tool used to measure and record the amount of electrical energy usage has a shortage of kWh meters can not be monitored remotely how much energy is used, so it is rather inconvenient for PLN officials to check the use of electricity for postpaid customers. This research was conducted to design a prototype of a wireless electrical energy transmission system and design a wireless electrical energy recording system using the NRF24L01 wireless transmitter module and the PZEM004T kWh meter module. The design in this study uses the principle of electromagnetic induction to transfer electrical energy at close range, while to transmit data, the authors use the NRF24L01 module. Besides, the authors use the PZEM004T module to measure various magnitudes. Based on the results of observations and measurements of the design of the tool, the authors found that the transmission of electrical energy using electromagnetic induction is not effective for longer distances because the energy lost in the air is getting bigger. So this technology needs to be further investigated. Besides, the measurement of electrical quantities using the PZEM module has a small difference (under 2%) with measurements using a multimeter, so it can be said that the measurement with the PZEM004T module is effective. </span></span>