scholarly journals An Electromagnetic Lock Actuated by a Mobile Phone Equipped with a Self-Made Laser Pointer

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1524 ◽  
Author(s):  
Jau-Woei Perng ◽  
Tung-Li Hsieh

The main purpose of this study was to create an acousto-optic control lock device to convert electrical signals with a specific sound command using an acousto-optic conversion module, thereby improving the reliability and safety of opening or closing remote controlled door locks, such as car central locks or rolling doors. We used music playing through a smart phone speaker to create a special laser pointer to connect with the smart phone‘s auxiliary input. The laser pointer (wavelength of 630–650 nm and maximum output of 5 mw) lights up when the smart phone’s music starts playing at a music frequency matching the light frequency. When the solar panel receives light, it converts the frequency of the light signal into an electrical frequency signal. The current is amplified using the power amplifier and then the amplified current flows to the sound recognition module. The sound recognition module performs audio comparison on the set sound signal, and once the comparison is correct, the output voltage activates the electromagnetic switch on the door to open or close it.

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3861
Author(s):  
Jie Mei ◽  
Qiong Fan ◽  
Lijie Li ◽  
Dingfang Chen ◽  
Lin Xu ◽  
...  

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Combining the Euler–Bernoulli beam theory and the D’Alembert principle, the differential dynamic equation of the doubly clamped energy harvester is derived, in which the excitation mode of axial load with pre-deformation is considered. A numerical solution of voltage amplitude and average power is obtained using the Rayleigh–Ritz method. Output power of 22.5 μW at 27.1 Hz, with the optimal load resistance being 1 MΩ, is determined by the frequency sweeping analysis. In order to power electronic devices, the converted alternating electric energy should be rectified into direct current energy. By connecting to the MDA2500 standard rectified electric bridge, a rectified DC output voltage across the 1 MΩ load resistor is characterized to be 2.39 V. For further validation of the mechanical-electrical dynamical model of the doubly clamped flexible piezoelectric energy harvester, its output performances, including both its frequency response and resistance load matching performances, are experimentally characterized. From the experimental results, the maximum output power is 1.38 μW, with a load resistance of 5.7 MΩ at 27 Hz, and the rectified DC output voltage reaches 1.84 V, which shows coincidence with simulation results and is proved to be sufficient for powering LED electronics.


2012 ◽  
Vol 24 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Ling Bu ◽  
Xiaoming Wu ◽  
Xiaohong Wang ◽  
Litian Liu

This article presents the modeling, fabrication, and testing of liquid encapsulated energy harvester using polyvinylidene fluoride electrets. Unlike harvesters reported in previous literature, this liquid encapsulated energy harvester uses flowing liquid rather than conventional resonating structures to induce variable capacitance and is more suitable for low-frequency applications. Prototypes injected with three types of liquid ( N-methyl-2-pyrrolidone, N, N-dimethylformamide, and glycerin) are tested in horizontal vibration and rotary motion mode, respectively. The results show that N, N-dimethylformamide–injected prototypes display the most desirable performance in horizontal vibration testing at 1–10 Hz due to high relative permittivity and low viscosity, with maximum output voltage of 2.32 V and power of 0.18 µW at 10 Hz. Glycerin-injected prototypes perform best at 0.1–1 Hz rotation due to effective movement and highest permittivity, with maximum output voltage of 11.46 V and power of 2.19 µW at 1 Hz.


Author(s):  
Sibel Akkaya Oy ◽  
Ali Ekber Özdemir

This manuscript presents a new experimental wind generator based on piezoelectric energy conversion for low power applications. The aim is to demonstrate an alternative renewable energy generation method for low power applications. The generator has four blades of a propeller equipped with a total of twenty-four (24) thin film piezoelectric transducers (TFPTs). The output voltage is generated using a newly developed circuit topology. The generator was tested at three wind speeds 10 m/s, 14 m/s and 18 m/s, with a maximum output voltage of 10.2 V being produced at a wind speed of 18 m/s. Results show that this generator has promise to be suitable for low power batteryless applications, for example wireless sensor nodes (WSN).


Author(s):  
Jui-Ta Chien ◽  
Yung-Hsing Fu ◽  
Chao-Ting Chen ◽  
Shun-Chiu Lin ◽  
Yi-Chung Shu ◽  
...  

This paper proposes a broadband rotational energy harvesting setup by using micro piezoelectric energy harvester (PEH). When driven in different rotating speed, the PEH can output relatively high power which exhibits the phenomenon of frequency up-conversion transforming the low frequency of rotation into the high frequency of resonant vibration. It aims to power self-powered devices used in the applications, like smart tires, smart bearings, and health monitoring sensors on rotational machines. Through the excitation of the rotary magnetic repulsion, the cantilever beam presents periodically damped oscillation. Under the rotational excitation, the maximum output voltage and power of PEH with optimal impedance is 28.2 Vpp and 663 μW, respectively. The output performance of the same energy harvester driven in ordinary vibrational based excitation is compared with rotational oscillation under open circuit condition. The maximum output voltage under 2.5g acceleration level of vibration is 27.54 Vpp while the peak output voltage of 36.5 Vpp in rotational excitation (in 265 rpm).


2019 ◽  
Vol 20 (1) ◽  
pp. 90-99
Author(s):  
Aliza Aini Md Ralib ◽  
Nur Wafa Asyiqin Zulfakher ◽  
Rosminazuin Ab Rahim ◽  
Nor Farahidah Za'bah ◽  
Noor Hazrin Hany Mohamad Hanif

Vibration energy harvesting has been progressively developed in the advancement of technology and widely used by a lot of researchers around the world. There is a very high demand for energy scavenging around the world due to it being cheaper in price, possibly miniaturized within a system, long lasting, and environmentally friendly. The conventional battery is hazardous to the environment and has a shorter operating lifespan. Therefore, ambient vibration energy serves as an alternative that can replace the battery because it can be integrated and compatible to micro-electromechanical systems. This paper presents the design and analysis of a MEMS piezoelectric energy harvester, which is a vibration energy harvesting type. The energy harvester was formed using Lead Zicronate Titanate (PZT-5A) as the piezoelectric thin film, silicon as the substrate layer and structural steel as the electrode layer. The resonance frequency will provide the maximum output power, maximum output voltage and maximum displacement of vibration. The operating mode also plays an important role to generate larger output voltage with less displacement of cantilever. Some designs also have been studied by varying height and length of piezoelectric materials. Hence, this project will demonstrate the simulation of a MEMS piezoelectric device for a low power electronic performance. Simulation results show PZT-5A piezoelectric energy with a length of 31 mm and height of 0.16 mm generates maximum output voltage of 7.435 V and maximum output power of 2.30 mW at the resonance frequency of 40 Hz. ABSTRAK: Penuaian tenaga getaran telah berkembang secara pesat dalam kemajuan teknologi dan telah digunakan secara meluas oleh ramai penyelidik di seluruh dunia. Terdapat permintaan yang sangat tinggi di seluruh dunia terhadap penuaian tenaga kerana harganya yang lebih murah, bersaiz kecil dalam satu sistem, tahan lama dan mesra alam. Manakala, bateri konvensional adalah berbahaya bagi alam sekitar dan mempunyai jangka hayat yang lebih pendek. Oleh itu, getaran tenaga dari persekitaran lebih sesuai sebagai alternatif kepada bateri kerana ia mudah diintegrasikan dan serasi dengan sistem mikroelektromekanikal. Kertas kerja ini  membentangkan reka bentuk dan analisis tenaga piezoelektrik MEMS iaitu salah satu jenis penuaian tenaga getaran. Penuai tenaga ini dibentuk menggunakan Lead Zicronate Titanate (PZT-5A) sebagai lapisan filem tipis piezoelektrik, silikon sebagai lapisan substrat dan keluli struktur sebagai lapisan elektrod. Frekuensi resonans akan memberikan hasil tenaga maksima, voltan tenaga maksima dan getaran jarak maksima. Mod pengendalian juga memainkan peranan penting bagi menghasilkan tenaga yang lebih besar. Reka bentuk yang mempunyai ketinggian dan panjang berlainan juga telah diuji dengan menggunakan bahan piezoelektrik yang sama. Oleh itu, projek ini akan menghasilkan simulasi piezoelektrik MEMS yang sesuai digunakan bagi alat elektronik berkuasa rendah. Hasil simulasi menunjukkan dengan panjang 31 mm dan ketinggian 0.16 mm, piezoelektrik PZT ini menghasilkan voltan maksima sebanyak 7.435 V dan tenaga output maksima 2.30 mW pada frekuensi resonans 40 Hz.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Min Zhang ◽  
Junlei Wang

A rigid circular cylinder with two piezoelectric beams attached on has been tested through vortex-induced vibrations (VIV) and wake-induced vibrations (WIV) by installing a big cylinder fixed upstream, in order to study the influence of the different flow-induced vibrations (FIV) types. The VIV test shows that the output voltage increases with the increases of load resistance; an optimal load resistance exists for the maximum output power. The WIV test shows that the vibration of the small cylinder is controlled by the vortex frequency of the large one. There is an optimal gap of the cylinders that can obtain the maximum output voltage and power. For a same energy harvesting device, WIV has higher power generation capacity; then the piezoelectric output characteristics can be effectively improved.


Author(s):  
Usman Latif ◽  
Ehtisham Ali ◽  
Emad Uddin ◽  
Zaib Ali ◽  
Muhammad Sajid ◽  
...  

Investigation of the energy harvesting from deep water waves by using flexible piezoelectric eel in a controlled environment is studied. Energy harvesting potential is examined as a function of streamwise distance from the fixed cylinder and spanwise gap along with the cylinder at different wave conditions. Output voltage and eel flapping behavior are dependent on cylinder vortices caused by local wavelength and wave amplitude. Maximum energy is harvested when the eel is placed near to the surface caused by high flapping amplitude and frequency. Similarly, at greater depth low flapping amplitude is observed resulting in small output voltage. Maximum output voltages are found at the shorter wavelength and at a streamwise distance of gx = 1.25 (where gx is the ratio of spacing “S” between cylinder and eel to the diameter of cylinder “D”) for all spanwise gaps along with the cylinder and minimum voltages are calculated at a longer wavelength and streamwise distance gx = 0.75. An increase of 65% in energy harvesting is observed by switching longer wavelengths (λ) to a shorter one and changing the piezo-eel spanwise gap from deep to the shallow depth. Whereas, an increase of 31.5% was found by keeping wavelength constant and changing the spanwise gap of eel. Furthermore, it is observed that energy harvesting from the wake of a bluff body in the wavy motion of water is sensitive to the wavelength and wave height.


Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 394 ◽  
Author(s):  
Dai-Van Vo ◽  
Minh-Khai Nguyen ◽  
Duc-Tri Do ◽  
Youn-Ok Choi

A novel single-phase nine-level boost inverter is proposed in this paper. The proposed inverter has an output voltage which is higher than the input voltage by switching capacitors in series and in parallel. The maximum output voltage of the proposed inverter is determined by using the boost converter circuit, which has been integrated into the circuit. The proposed topology is able to invert the multilevel voltage with the high step-up output voltage, simple structure and fewer power switches. In this paper, the circuit configuration, the operating principle, and the output voltage expression have been derived. The proposed converter has been verified by simulation and experiment with the help of PSIM software and a laboratory prototype. The experimental results match the theoretical calculation and the simulation results.


Electronics ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 592 ◽  
Author(s):  
KangHyun Yi

This paper analyzes the output voltage of an inductive wireless power transfer (WPT) depending on coupling conditions. When the optimum efficiency and maximum output power are obtained, it is called critical coupling, so the receiving coil and the transmitting coil should be separated by a certain distance. When the distance between the transmitting coil and receiving coil is very short, it is called over coupling, and output power decreases with the optimal operating state of the critical coupling condition. To design the entire circuit system for the inductive WPT depending on the coupling condition, it is beneficial to analyze the output voltage according to a load variation, an input voltage, and an operating frequency. Therefore, the output voltage depending on the coupling condition in the inductive WPT is analyzed in this paper. The output voltage gain in critical coupling condition is greater than one and is not affected by a load variation by a series LC resonant operation. The reduced output power in an over coupling condition can be recovered by a series LLC resonant operation. In addition, the output voltage gain is almost one and is affected by the load variation in the over coupling condition. A 5W prototype is implemented with the wireless power consortium standard coils and experimental results are shown to verify theoretical analysis and operation.


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