Magneto elasticity: Soft sensor measures fatigue in real time
Fatigue can often only be measured in real time using complex systems. A simple soft sensor uses magneto elasticity and even works wirelessly.
The tiredness sensor records the frequency of blinking and uses this to determine the level of tiredness.
(Image: Jun Chen Lab/UCLA)
A research team at the University of California, Los Angeles (UCLA) has developed a magneto elastic soft sensor that can determine a person's level of fatigue based solely on eye movements. Attached to the eyelid, it detects the frequency of blinking via the magnetic changes in the sensor material and deduces the wearer's fatigue from this.
Until now, tiredness has been determined either using complex measuring systems such as camera-based systems and electroencephalography (EEG) or by asking people about their level of tiredness. However, these methods can only be implemented reasonably reliably in laboratory environments; reliable real-time data cannot be collected via surveys. This is where the UCLA sensor comes into play, which measures fatigue as a mental state triggered, for example, by a drop in performance due to stress, lack of sleep, excessive activity or other influences. The scientists describe the sensor in the study "A soft magneto elastic sensor to decode levels of fatigue", which was published in Nature Electronics.
Magneto elasticity
The sensor technology consists of a conductive gold coil that is applied to a thin, thermoplastic elastomer. The elastomer is covered with a magneto elastic film containing tiny magnets. This plaster-like sensor is stuck to the eyelid. When blinking, high-precision electrical signals are generated by magnetic field fluctuations due to the magneto elasticity, which can then be evaluated. The advantages: The sensor works wirelessly and does not require a separate power supply, making it suitable for a wide range of everyday applications.
The sensor can be kept very thin thanks to the materials used, and is still protected against sweat and moisture. The problem with such sensors is that they usually have to be encapsulated for extra protection. This typically makes them thicker, which can impair their function and wearing comfort.
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The technology of the soft sensor based on magneto elasticity can also be extended to other medical areas, the researchers write. Conceivable applications include pulse wave monitoring, enabling speech without vocal cords and permanent respiratory and cardiovascular monitoring. The scientists therefore want to intensify their research into the use of magneto elasticity in the future.
(olb)
