humans blink 15-20 times per minute – about 10,000 times a day! some researchers I am interested in monitoring blinks. For example, humans blink more when they are tired. If we could monitor our blinks while driving, it could reduce traffic accidents by alerting us when we are too tired to drive safely. Alternatively, a person who cannot speak due to an injury or disability can communicate by blinking, which may be translated by a computer.
Current methods of eye blink monitoring have many limitations. 1 It uses a camera to capture an image of the eye, but requires high computational power. Poor lighting can also degrade image quality. another It relies on tiny sensors attached to the skin near the eyes. This can be uncomfortable and not very portable.yet another way It uses infrared to monitor blinks, but it comes with many safety risks.
Chinese researcher Recently, we developed a small device integrated into eyeglasses that can reliably track blinks with ultrasound. Ultrasound is a common medical imaging tool that measures high-energy sound waves bouncing off objects. Ultrasound is also not affected by dark lighting and is known to be eye safe.
To keep the device small and light, scientists used a technique called microelectromechanical system, or MEMS for short. MEMS technology combines electrical and mechanical components into tiny devices, typically less than 1 mm.Scientists have determined the top and bottom electrodes, and piezoelectric Layers sandwiched between. Piezoelectrics are unique materials that accumulate an electric charge in response to physical forces such as sound waves, making them excellent materials for ultrasonic detection. Scientists chose aluminum nitride as the piezoelectric layer because it is non-toxic and highly sensitive to vibration.
Such a single MEMS layered structure is transducer, is so small that it does not produce a strong signal by itself. To amplify it, the scientists connected several transducers in a 15 x 15 array, resulting in a chip measuring just 2.5 mm x 2.5 mm. I then stuck this little chip onto my glasses.
The transducer is electrically excited in air and vibrates due to the piezoelectric effect. This vibration emits ultrasonic waves. When you wear glasses, ultrasound waves are reflected from your eyes and eyelids. This reflected wave creates a signal within the transducer. Using the laws of physics, scientists calculated the distance traveled by the reflected wave. Because of the eyelids, they are slightly longer when the eyes are open and shorter when they are closed.
To evaluate the new device, scientists performed a battery of blink tests. First, they collected data with only one eye open or closed. For open eyes, the reflected wave was measured at 72 microseconds. The reflected wave was measured at 51 microseconds when the eyes were closed. The scientist calculated a change in distance of 3.6 mm, which corresponds to the thickness of the human eyelid. We then ran tests to make sure we could reliably measure similar changes with both eyes open, or with both eyes closed, and with one eye open and one eye closed.
The scientists then ran these tests on six people to see if the device worked with different eye shapes and eyelid thicknesses. I succeeded in detecting whether it is closed. However, the measured time for the reflected wave to return to the device varied among volunteers due to differences in eyelid and eye shape. This result shows that it is not the exact time that is important in determining whether a person’s eyes are open or closed, but the time difference between the measurements.
Finally, the scientist wanted to observe the device in real time. They designed a computer His algorithm that records the ultrasound waves measured by the transducer His device, calculates the time difference between each reflected wave, and outputs whether a person’s eyes are open or closed. They were able to monitor a person’s eyes for one minute and found that they were able to record blinks in real time.
Scientists in this study designed and built a small device attached to eyeglasses that reliably detects and records whether a person’s eyes are open or closed. This device is not only reliable, but portable and safe. The authors suggest longer-term testing on humans and additional studies to optimize the design such as circuit size and other features.
