Fujitsu Ltd has developed a wearable sensor that measures the pulse wave of a driver, decides whether the driver is drowsy and alerts the driver.
The sensor, FEELythm, will be released in February.
The main unit of FEELythm, which weighs about 90g, is hung from a neck, and a clip-like sensor is attached to an earlobe to measure pulse wave. The sensor is equipped with an LED lamp (infrared region), and pulse wave data is obtained from a light that has passed the earlobe. This method enables to measure pulse wave more accurately than methods using a wrist (whose movements can become noise), reflected light, etc, Fujitsu said.
Measurement results are transmitted to a smartphone, etc via Bluetooth Low Energy. And an algorithm developed by Fujitsu is used for frequency analysis to detect the driver’s drowsiness. When the drowsiness becomes stronger, the parasympathetic nerve becomes predominant, reducing the frequency fluctuation of pulse wave, the company said. When the sensor detects drowsiness, the main unit vibrates, or the smartphone plays a voice message.
Fujitsu also employed measures to reduce the variation in measurement results caused by individual differences and devices. Specifically, the company added an automatic calibration function that corrects deviations from the standard value and a learning function that helps perform optimal calibration for each driver. The calibration value for each driver is stored in a cloud server, and the value is updated with the learning function, enabling to set an optimal value.
Fujitsu said it has been developing the elemental technologies of FEELythm for about 10 years.
“We aim to make it possible to collect data other than drowsiness data such as fatigue data and develop a product for general consumers,” the company said.