Nanogenerator-powered acceleration sensor

(Nanowerk News) In new work just published in ACS Nano ("Self-Powered Acceleration Sensor Based on Liquid Metal Triboelectric Nanogenerator for Vibration Monitoring"), researchers have demonstrated a self-powered acceleration sensor based on liquid metal triboelectric nanogenerator (TENG), which was composed of an inner liquid metal droplet (mercury) and an outer acrylic shell.
Structural design of the self-powered acceleration sensor
Structural design of the self-powered acceleration sensor. (a) Schematic diagram of the self-powered acceleration sensor for vibration monitoring. (b) Photograph of the nn-PVDF film composed of nanofibers. (c) SEM image of PVDF nanofibers. (d) Photograph of the fully assembled acceleration sensor. (© ACS)
The device is capable of vibration measurement and analysis in real time.
The team, led by Prof. Zhong Lin Wang at Georgia Tech, utilized an electrospinning method to fabricate the nanofiber-networked polyvinylidene fluoride (PVDF) film, which was beneficial to enhance the output of TENG.
To prove the capability of the liquid metal TENG as an acceleration sensor for vibration measurement and analysis, four sets of practical applications were demonstrated:
  • The acceleration sensor was mounted onto an automotive engine and efficiently detected the operating state. The open-circuit voltage rapidly increased to 2.5 V as the car started, then dropped to nearly 0.25 V and kept until the car stopped.
  • Similarly, the acceleration sensor also can be fixed on the mechanical equipment such as air compressor to monitor the operating state.
  • The third practical application shows that the acceleration sensor, mounted on a firm table, can detect the vibration of the table caused by the impact between a little ball and the table.
  • The acceleration sensor was embedded in the shoes for human gait analyzing in real time. When a human first begins to exercise, the frequency and acceleration of falling steps could be detected by the self-powered human gait analysis system.
  • The researchers systematically investigated the relationship between the electric output properties and the vibration acceleration. The output voltage and current exhibit a good linear relationship with the external acceleration.
    The acceleration sensor shows good performance with the detection range from 0 to 60 m/s2 and sensitivity of 0.26 V·s/m2.
    The liquid metal mercury drop could significantly enhance the stability and durability of the acceleration sensor. The output voltage and current show negligible drops after nearly 200,000 cycles.
    Furthermore, a high-speed camera with a frame rate of 4000 Hz was employed to dynamically monitor the working process of the acceleration sensor.
    The acceleration sensor was very sensitive to small ambient vibrations, such as machine vibration and table vibration.
    "This work not only demonstrates a self-powered acceleration sensor with high sensitivity and wide detection range but also expands TENG’s application in self-powered sensing systems," the authors conclude their article.
    Michael Berger By – Michael is author of three books by the Royal Society of Chemistry:
    Nano-Society: Pushing the Boundaries of Technology,
    Nanotechnology: The Future is Tiny, and
    Nanoengineering: The Skills and Tools Making Technology Invisible
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