Articles tagged with "energy-harvesting"
Gold nanoparticles boost solar efficiency by capturing full spectrum
A research team from Korea University has developed a novel gold nanoparticle material called "supraballs" that significantly enhances solar energy absorption by capturing nearly the entire solar spectrum. Unlike traditional gold or silver nanoparticles, which primarily absorb visible wavelengths and thus only a fraction of sunlight, these supraballs are self-assembled clusters of gold nanoparticles optimized in size to absorb a broader range of wavelengths. When applied as a coating on a commercial thermoelectric generator (TEG), the supraballs nearly doubled solar absorption compared to conventional gold nanoparticle films, achieving about 89 percent absorption versus 45 percent. The team used computer simulations to design and optimize the supraballs for maximum sunlight absorption, predicting over 90 percent efficiency, which was then validated through real-world testing under ambient conditions without specialized equipment. This coating technology offers a simple and cost-effective method to improve solar-thermal and photothermal systems, potentially lowering barriers to high-efficiency solar energy harvesting in practical applications. The study detailing these findings
energysolar-energygold-nanoparticlesnanomaterialsphotovoltaic-technologysolar-absorptionenergy-harvestingReal Dyson spheres? How alien megastructures might survive in space
A recent study by Professor Colin McInnes at the University of Glasgow explores the feasibility and stability of hypothetical megastructures known as Dyson spheres, which advanced alien civilizations might build to harvest energy from their stars. Dyson spheres, first proposed by Freeman Dyson in 1960, include various concepts such as stellar engines—large reflective disks that harness a star’s power to generate thrust—and Dyson bubbles, swarms of small energy-harvesting spacecraft surrounding a star. A major challenge for these structures is maintaining gravitational stability, as larger megastructures tend to be inherently unstable. McInnes developed mathematical models treating Dyson spheres as extended objects influenced by realistic gravitational and radiation-pressure forces. His findings suggest that stellar engines could achieve passive stability if their mass is concentrated in an outer supporting ring rather than uniformly distributed. Similarly, Dyson bubbles could remain stable if composed of a sufficiently large number of low-mass reflectors arranged densely enough to avoid gravitational instabilities. This research not only advances theoretical understanding of such
energyDyson-spherestellar-enginesspace-megastructuresenergy-harvestinggravitational-stabilityastrophysicsNLR Advances Battery-Free Power for Remote Maritime Sensors and Navigation Aids - CleanTechnica
The National Laboratory of the Rockies (NLR), part of the U.S. Department of Energy, is developing a compact thermomagnetic generator designed to power remote maritime sensors and navigation aids without batteries. This technology, inspired by 19th-century concepts from Nikola Tesla and Thomas Edison, exploits natural temperature differences between ocean water and ambient air to generate electricity on a small scale—producing milliwatts sufficient for wireless sensor operation. The generator uses gadolinium, a rare earth element whose magnetism changes near room temperature, cycling across its Curie point as ocean and air temperatures fluctuate, thus creating a continuous electric current. After successful prototype testing in controlled freshwater environments, the NLR team is advancing toward ocean field trials, focusing on device durability and corrosion resistance in harsh marine conditions. The researchers envision these thermomagnetic generators enabling reliable, maintenance-free power for distributed ocean monitoring systems, enhancing capabilities in marine exploration and offshore applications. Funded by the Department of Energy’s Water Power Technologies Office, this
energythermomagnetic-generatormarine-sensorswireless-sensorsgadoliniumenergy-harvestingremote-powerPhotos: These kinetic solar crown clusters could generate 210,000 kWh of energy annually
The Fiji Solar Crown, developed by MASK Architects in collaboration with TesserianTech, is an innovative solar-integrated living system designed to address energy and water challenges in island nations like Fiji. This system features a Dual-Axis Concave Mirror Crown that transforms residential units into self-sustaining power plants, combining cultural respect with advanced engineering. Inspired by traditional Fijian bure architecture, the design replaces the roof apex with a parabolic solar mirror that tracks the sun with dual-axis rotation, optimizing solar energy capture while also harvesting rainwater and providing shading to create a cooled microclimate. The system is modular, available in three sizes—3, 5, and 7 meters in diameter—each tailored to different community needs, from localized agricultural power to residential use in floating villas or hilltop homes. The flagship 7-meter module, arranged vertically over three levels, supports residential living with communal, domestic, and observation spaces. Clusters of these units can generate substantial energy, with ten
energysolar-energyrenewable-energysolar-powerenergy-harvestingsustainable-architecturedual-axis-solar-trackingMaxell Develops All-Solid-State Battery Power Module Compatible with ER Battery Size - CleanTechnica
Maxell has developed an all-solid-state battery power module that matches the size and output voltage (3.6V) of the commonly used lithium thionyl chloride (ER) battery. ER batteries are widely employed in industrial equipment backup systems, smart meters, and IoT sensors but are primary (non-rechargeable), necessitating frequent replacements that increase maintenance workload and generate waste. Maxell’s new module fits within the standard ER battery dimensions (17.9 mm diameter, 50 mm height) and incorporates eight mass-produced “PSB401010H” cells to provide approximately 35 mAh capacity. It also includes an integrated charging circuit (charging at 5V), enabling easy adoption as a rechargeable replacement for ER batteries. By using this all-solid-state battery module, industries can reduce battery replacement frequency, thereby lowering maintenance time and increasing equipment operating hours, which enhances productivity. Additionally, the rechargeable nature of the module helps minimize environmental impact by reducing waste battery disposal. Maxell is focusing
energyall-solid-state-batterybattery-technologyIoT-sensorsindustrial-equipmentenergy-harvestingwireless-power-transferElon Musk says Tesla’s restarted Dojo3 will be for ‘space-based AI compute’
Elon Musk announced that Tesla plans to restart development of its third-generation AI chip, Dojo3, but with a new focus on “space-based AI compute” rather than training self-driving models on Earth. This marks a strategic shift following Tesla’s shutdown of the original Dojo supercomputer project five months earlier, which included disbanding the Dojo team after the departure of its lead, Peter Bannon. At that time, Tesla had intended to rely more on external partners like Nvidia, AMD, and Samsung for AI compute and chip manufacturing. However, Musk’s recent statements suggest a renewed commitment to in-house chip development, highlighting that Tesla’s AI5 chip design is progressing well and that the upcoming AI7/Dojo3 chip will be geared toward operating AI data centers in space. Musk’s vision aligns with broader industry discussions about the limitations of Earth’s power grids and the potential benefits of off-planet data centers powered by constant solar energy. Tesla aims to rebuild its Dojo team
AI-chipsTesla-Dojospace-based-computingenergy-harvestingsemiconductor-technologyautonomous-drivingAI-hardwareChina-Chile team launch mission to study 435-mile-deep Atacama Trench
A joint China-Chile expedition has launched a three-month mission (January–March) to explore a 435-mile section of the Atacama Trench, a deep subduction zone in the eastern Pacific Ocean where the Nazca and South American tectonic plates collide. Operating from the Chilean port of Valparaiso, the mission is led by Chinese researcher Du Mengran and represents the largest deep-sea operation ever conducted in the region. The expedition utilizes the advanced Chinese manned submersible Fendouzhe ("Striver"), capable of reaching depths over 10,000 meters, allowing scientists to directly observe and sample the trench’s extreme environment, including chemosynthetic life forms that survive without sunlight. The mission aims to address three critical scientific frontiers: improving understanding of seismic activity to enhance tsunami and earthquake disaster prevention, investigating the trench’s role in global carbon cycling, and searching for rare biochemical compounds that could lead to medical breakthroughs. The team employs cutting-edge technology such as autonomous robotic
robotdeep-sea-submersibleautonomous-robotic-landerssensorsenergy-harvestingmaterials-scienceocean-explorationBladeless Tesla turbine turns static electricity into usable power
Researchers have developed a bladeless Tesla turbine-based system that converts static electricity generated in compressed air into usable electrical power. Inspired by Nikola Tesla’s 1913 patent for a bladeless turbine that uses viscous drag on smooth, closely spaced discs rather than traditional angled blades, the new device harnesses the triboelectric effect—static charges produced by friction between particles and pipe surfaces in compressed air systems. The turbine spins at high speeds (up to 8472 rpm at 0.2 MPa pressure) driven solely by the viscous force of swirling compressed air reaching 300 m/s, generating peak electrical outputs of 800 volts and 2.5 amps at 325 Hz without additional particles. This technology offers a dual benefit for industrial facilities already using compressed air by both generating electricity and neutralizing static charges through the production of negative ions, which also helps collect dust and moisture, improving air quality and safety. By integrating century-old turbine principles with modern triboelectric materials and electronics, the
energyTesla-turbinestatic-electricitytriboelectric-materialsenergy-harvestingindustrial-applicationscompressed-airRobot rovers to cars: 7 solar innovations shaping the future energy shift
At CES 2026, solar technology showcased a significant evolution beyond traditional rooftop panels, emphasizing adaptability, automation, and integration into diverse environments. Key innovations included Jackery’s “Living Solar” ecosystem featuring the Solar Mars Bot, a mobile rover with retractable solar panels that autonomously tracks sunlight for optimal energy capture, and the Solar Gazebo, a fixed outdoor structure with a louvered solar roof producing up to 10 kWh daily. These systems highlight how automation can enhance solar efficiency while simplifying user interaction. Other standout technologies focused on expanding solar’s applicability and ease of installation. Blue Device introduced nanoparticle solar smart windows that generate power and dynamically tint without internal wiring, reducing building energy use by 20-40% and cutting installation costs by over half. BiLight Innovations presented a rollable perovskite photovoltaic curtain that functions as both a shading device and power source, demonstrating flexible, lightweight solar materials suitable for indoor and low-light conditions. Additionally, Dracula Technologies unveiled the LAYER®
robotsolar-energyautonomous-systemsenergy-harvestingsmart-windowsperovskite-solar-cellsflexible-solar-technologyBlink-powered eye tracker could let paralyzed patients control chairs
Researchers at Qingdao University in China have created a novel, lightweight, and self-powered eye-tracking system aimed at aiding individuals with severe mobility impairments, such as those with Amyotrophic Lateral Sclerosis (ALS). Unlike conventional eye trackers that are often heavy, reliant on external power sources, and ineffective in low-light conditions, this new device harnesses energy generated by the user's blinking through triboelectric nanogenerators. By converting the mechanical energy from eyelid movements into electrical power, the system operates without batteries or external power, maintaining clinical precision with 99% accuracy and the ability to detect eye movements as small as 2 degrees—even in electromagnetically noisy environments. The device's friction-based energy harvesting also serves as a sensitive sensor, enabling it to function effectively in total darkness and without causing eye strain, unlike infrared camera-based trackers. Tested for biocompatibility on rabbit eyes, the system showed no irritation and retained its charge well. Beyond assisting patients with mobility challenges,
energytriboelectric-nanogeneratorsself-powered-deviceseye-tracking-technologyassistive-technologywearable-sensorsenergy-harvestingFirst self-powered quantum microwave signal achieved in experiment
Researchers from Vienna University of Technology (TU Wien) and Okinawa Institute of Science and Technology (OIST) have experimentally demonstrated the first self-induced superradiant masing—microwave signal generation without external driving forces. Superradiance, a quantum optics phenomenon where atoms or quantum dots emit intense, coherent light pulses collectively, was traditionally associated with energy loss and short bursts. However, the team observed a novel behavior where quantum particles, specifically electron spins in nitrogen-vacancy (NV) centers within diamond ensembles, self-sustain long-lived, stable microwave pulses through intrinsic spin–spin interactions. This self-organization from seemingly disordered spin interactions produces a coherent microwave signal, revealing a fundamentally new mode of collective quantum behavior. The discovery challenges previous assumptions that interactions among quantum particles disrupt coherence, showing instead that these interactions can fuel and maintain quantum emission. Large-scale computational simulations confirmed that spin interactions continually repopulate energy levels, sustaining the superradiant reaction over extended periods. This breakthrough opens new avenues for
quantum-technologymicrowave-signalssuperradianceenergy-harvestingquantum-sensorsquantum-materialsspintronicsChina’s 6G surface converts enemy radar beam into power for stealth jets
Chinese researchers have developed a novel smart electromagnetic surface based on reconfigurable intelligent surface (RIS) technology that can convert ambient electromagnetic waves—such as enemy radar beams—into electrical power. This innovation enables stealth jets to harvest energy directly from radar signals, eliminating the need for traditional batteries and supporting the concept of "electromagnetic cooperative stealth," where multiple networked platforms coordinate to minimize radar visibility. The RIS is a two-dimensional reflecting material capable of real-time manipulation of electromagnetic waves, allowing simultaneous wireless information transfer, sensing, and energy harvesting. Beyond military applications, this technology is poised to impact 6G telecommunications by integrating data transmission with radar-like functions, optimizing spectrum and hardware usage. Current prototypes demonstrate effective beam steering and the ability to create intentional radio dead zones, enhancing signal coverage and security. The RIS platform offers a low-cost, programmable solution that reduces physical hardware requirements and can support environment-adaptive micro base stations and self-powered relay systems. Researchers anticipate that as this technology matures, it will
6Genergy-harvestingreconfigurable-intelligent-surfaceelectromagnetic-stealthInternet-of-Robotic-Thingswireless-power-transferIoTLead-free hybrid material turns motion into powerful electric charge
Researchers from the University of Birmingham, Oxford, and Bristol have developed a new lead-free hybrid piezoelectric material based on bismuth iodide that efficiently converts mechanical motion into electricity. This soft, durable material matches the performance of conventional lead-based ceramics like lead zirconate titanate (PZT) but avoids the environmental and health hazards associated with lead. Unlike PZT, which requires high-temperature processing (~1000°C), the bismuth-iodide hybrid can be synthesized at room temperature, making it easier and greener to produce. This innovation holds promise for powering sensors, wearable devices, medical implants, and flexible electronics in a more sustainable way. The team used advanced characterization techniques, including single-crystal X-ray diffraction and solid-state nuclear magnetic resonance (NMR), to reveal that halogen bonding between the organic and inorganic components is key to the material’s piezoelectric properties. This bonding induces a subtle structural instability that breaks symmetry, enhancing the piezoelectric response without the drawbacks of traditional
materialspiezoelectricenergy-harvestinghybrid-materialsbismuth-iodideflexible-electronicssustainable-technologyScrew It or Pump It? BYD Patents Two Paths to Suspension Energy Recovery - CleanTechnica
The article discusses two innovative suspension energy recovery systems recently patented by BYD, highlighting the company's exploration of different methods to capture and reuse energy typically lost in vehicle suspension damping. Traditional shock absorbers convert suspension motion energy into heat through hydraulic fluid resistance, which cannot be reused. BYD’s patents aim to actively recover this energy, potentially improving overall vehicle efficiency or offsetting the energy consumption of advanced suspension control systems. The article explains the basics of suspension function and existing damper technologies, including passive, adaptive, and active suspensions, setting the context for BYD’s new approaches. The first patented design involves a ball screw mechanism where an intermediate fitting with permanent magnets acts as a rotor between the inner shaft and outer housing. This rotor spins as the suspension moves, inducing electricity in a coil to generate power. This design could offer a more compact vertical profile, beneficial for vehicle packaging constraints, though it may be wider than traditional dampers. Mechanically, it integrates the motor/generator within the damper
energysuspension-energy-recoveryBYD-patentsactive-suspensionvehicle-efficiencymagnetorheological-fluidenergy-harvestingHow Energy-Generating Sidewalks Work
The article explores the concept and mechanics behind energy-generating sidewalks, which capture the energy produced by human footsteps and convert it into usable electricity. This technology has been implemented in various countries and has potential applications ranging from powering city infrastructure to energizing entertainment venues like discotheques or playgrounds. The fundamental principle relies on the physics of energy conservation, illustrated through the analogy of a bouncing ball that exchanges kinetic, gravitational potential, and spring potential energy, with some energy lost as heat or sound during each impact. Humans maintain a constant height while walking by replenishing lost energy through muscular effort fueled by food, meaning the system is not closed but continuously energized internally. Energy-harvesting sidewalks capitalize on the otherwise "wasted" kinetic energy from footsteps using two main technologies: piezoelectric generators, which produce electricity when mechanical stress is applied to certain materials, and electromagnetic generators, which convert mechanical motion into electrical energy. Both methods have long-standing scientific foundations, but their novel application in pedestrian pathways presents an
energyrenewable-energyenergy-harvestingkinetic-energysustainable-technologyenergy-generating-sidewalksgreen-technologyNew solar desalination device makes 3.4 liters of drinking water hourly
Researchers at Ulsan National Institute of Science & Technology (UNIST) have developed an innovative solar desalination device that produces clean drinking water by harnessing sunlight to evaporate seawater without relying on external electricity. Central to this technology is the use of La0.7Sr0.3MnO3, an oxide perovskite material that efficiently converts solar energy into heat through intra-band trap states, facilitating non-radiative recombination of photoexcited electrons and holes. This material, combined with a novel inverse-L-shaped device design that enables one-directional fluid flow, effectively prevents salt accumulation by pushing salt to the edges of the photothermal surface, thereby reducing fouling and light blockage. The system achieves a remarkable solar evaporation rate of 3.40 kg/m²/h (approximately 3.4 liters per hour), significantly outperforming typical rates of 0.3–0.4 kg/m²/h under natural sunlight. Durability tests confirmed stable operation over two weeks
solar-desalinationenergy-harvestingphotothermal-materialsoxide-perovskiterenewable-energywater-purificationadvanced-energy-materialsChina develops transparent coating to turn windows into solar panels
Researchers at Nanjing University in China have developed a transparent, colorless solar concentrator coating that can be applied directly to standard window glass, enabling windows to generate solar power without altering their appearance. This innovation uses multilayer cholesteric liquid crystal (CLC) films to selectively diffract circularly polarized sunlight, guiding it toward photovoltaic (PV) cells installed at the window edges. Unlike conventional solar concentrators, this system maintains high visual clarity with an average visible transmittance of 64.2% and a color rendering index of 91.3%, allowing up to 38.1% of incident sunlight to be harvested while keeping the glass visually indistinguishable from ordinary windows. The technology offers significant scalability and efficiency advantages. Simulations indicate that a two-meter-wide coated window can concentrate sunlight up to 50 times its normal intensity, potentially reducing the required PV cell area by 75%, lowering material costs, and enabling new energy-efficient building designs. A prototype demonstrated the ability to power
energysolar-powertransparent-coatingphotovoltaic-cellsliquid-crystal-filmsenergy-harvestinggreen-buildingsChina’s nanogenerators achieve 117% power conversion from ocean waves
Chinese researchers from the Beijing Institute of Nanoenergy and Nanosystems and Guangxi University have developed advanced triboelectric nanogenerators (TENGs) capable of converting low-frequency mechanical energy from ocean waves into electricity with an unprecedented 117% power conversion efficiency. Their work, published in Nano-Micro Letters, reviews six innovative TENG structural designs optimized for marine environments, including spherical, bionic, and hybrid configurations. These designs enhance internal device output, durability, and adaptability to harsh ocean conditions, enabling self-sustaining power solutions for marine grids, distributed IoT, and even hydrogen production from seawater. The study emphasizes advancements in TENG architectures, particularly solid-solid contact designs, which show strong commercial potential for marine power generation. The researchers highlight the importance of structural optimization and hybrid systems that integrate TENGs with electromagnetic generators (EMGs), piezoelectric generators (PENGs), and solar cells to capture a broader energy spectrum. Such hybrid systems achieve frequency-complementary
energynanogeneratorsocean-wave-energytriboelectric-nanogeneratorsblue-energymarine-power-generationenergy-harvestingCoin-sized generator harvests energy from waste walnut shells
Researchers at the University of Waterloo have developed a coin-sized water-induced electric generator (WEG) that produces electricity by harnessing the evaporation of water from walnut shells, an abundant agricultural waste. This device leverages hydrovoltaic energy harvesting, where evaporating water moves charged ions through the porous walnut shell structure, creating an electrical current without complex processing. The WEG can generate enough power to operate small electronics like calculators, demonstrating a simple, low-cost, and sustainable approach to energy generation from natural waste materials. Among various nut shells tested, walnut shells showed the highest efficiency, especially after cleaning, polishing, and precise shaping. The WEG units consist of treated walnut shells combined with electrodes, wires, and a 3D-printed casing. By connecting multiple units, the researchers successfully powered an LCD calculator, highlighting potential applications in remote or off-grid settings. Future research aims to develop wearable versions that harvest energy from sweat or raindrops and explore practical uses such as water-leak sensors.
energyrenewable-energyhydrovoltaic-energyenergy-harvestingsustainable-poweragricultural-wasteclean-electricitySelf-powered microneedle patch monitors biomarkers without blood
Researchers have developed a self-powered microneedle patch that enables painless, blood-free collection of health biomarker samples from dermal interstitial fluid (ISF) just below the skin’s surface. Unlike traditional blood tests, which require needles and complex processing to isolate relevant fluids, this patch uses microneedles that swell upon contact with ISF, drawing the fluid into a paper layer where it is stored. The patch can collect and store biomarkers for up to 24 hours, allowing for easier and faster health monitoring without the need for batteries or external devices. In proof-of-concept tests on synthetic skin, the patch successfully measured cortisol, a stress biomarker, within 15 minutes, demonstrating potential for frequent, noninvasive monitoring of various health indicators. Made from inexpensive materials, the patch eliminates the need for phlebotomists and blood collection supplies, potentially transforming home and clinical diagnostics. The research team is advancing human trials and developing electronic readers to analyze the collected samples, seeking industry
materialsenergy-harvestingwearable-technologybiosensorshealth-monitoringmicroneedlesself-powered-devicesMelting ice races faster than Death Valley rocks on new lab surface
Researchers at Virginia Tech, led by Professor Jonathan Boreyko, have engineered a specially designed aluminum surface that causes melting ice discs to self-propel rapidly across it. The surface features asymmetric, arrowhead-shaped grooves with a herringbone pattern that direct the flow of meltwater, effectively carrying the ice disc forward without external forces like wind. This phenomenon was inspired by the natural mystery of "sailing stones" in Death Valley's Racetrack Playa, where rocks move across flat ground due to ice rafts propelled by wind and melting water. A surprising discovery emerged when the team applied a water-repellent coating to the grooved plates. Instead of facilitating faster movement, the ice disc initially stuck to the surface, creating a "slingshot effect." Meltwater pooling on one side of the ice disc generates a surface tension imbalance that suddenly dislodges and propels the ice at high speed, making it move much faster than the Death Valley rocks. This breakthrough has potential applications in rapid defrost
energymaterialsenergy-harvestingice-propulsionsurface-engineeringdefrosting-technologybiomimicryTiny turbines crack wind’s secret ‘twist’ for a giant 37% power boost
Researchers led by Shuo Zhang have discovered that pairing two tiny, counter-rotating wind turbines in tandem can increase power output by 37% compared to a single turbine. These micro wind turbines, less than 200 millimeters in diameter, are crucial for powering remote and decentralized technologies such as environmental sensors and IoT devices. Using stereoscopic particle image velocimetry, a 3D airflow visualization technique, the team analyzed the wake—turbulent airflow—behind the first turbine and found it retains significant rotational energy typically lost. By positioning a second turbine counter-rotating behind the first at a specific distance (12 radii), this residual rotational energy can be harnessed, boosting overall efficiency. The enhanced performance stems from the unique physics of small turbines, which operate at lower speeds and higher torque, imparting a “twist” to the wind that the downstream turbine can exploit. This tandem design mimics multi-stage turbines in jet engines by capturing both the wind’s push and twist
energywind-turbinesmicro-wind-turbinesrenewable-energyenergy-harvestingIoT-devicessustainable-powerUS scientists shatter 165-year-old physics rule for energy breakthroughs
A research team at Penn State has reported a groundbreaking violation of Kirchhoff’s law of thermal radiation, a fundamental physics principle established 165 years ago. Kirchhoff’s law states that a material’s ability to absorb energy at a specific wavelength and angle must equal its ability to emit energy under the same conditions. However, the Penn State scientists demonstrated a significant non-reciprocity contrast of 0.43—indicating a notable difference between absorptivity and emissivity—using a specially designed five-layer thin film semiconductor structure. This effect was observed over a broad 10-micrometer wavelength range, marking the strongest recorded deviation from the law’s reciprocity principle. This breakthrough has important implications for energy harvesting and thermal management technologies. For example, conventional solar cells must emit some absorbed energy back to the sun, which limits their efficiency. The new non-reciprocal material can direct emitted energy away from the sun, potentially allowing that energy to be captured by additional solar cells and thus improving overall
energythermal-radiationKirchhoff's-lawnon-reciprocitythin-film-materialsenergy-harvestingsemiconductor-materialsPhysicists create world’s smallest violin that’s thinner than hair
materialsnanotechnologynanolithographyelectronicsenergy-harvestingprecision-engineeringmicrofabricationUS scientists harvest electrical energy from human movement
energytriboelectric-generatorenergy-harvestingwearable-biosensorsmechanical-energypower-generationsensors