The principle of measuring bracelet pressure is photoelectric transmission measurement. In principle, the sensor that contacts the bracelet with the skin will emit a beam of light to irradiate the skin and measure the reflected/transmitted light.
Because blood absorbs light with a specific wavelength, every time the heart pumps blood, that wavelength will be absorbed in large quantities. Blood is red, reflecting red light and absorbing green light, so that the heartbeat can be determined. Mi band combines green LED light with photosensitive photodiode to detect the blood circulation at the wrist at a specific time, thus obtaining the heart rate information.
Related knowledge:
On June 1 1 day, 2020, Xiaomi officially announced the main configuration, function upgrade and many new functions of mi band 5. It supports more than 100 theme dials, has 1 1 professional sports modes, and provides deep blue, dynamic orange, lotus root starch, vibrant yellow and bronze purple.
The most important thing is to upgrade the new sensor. It has the functions of 24-hour heart rate sleep monitoring, stress monitoring, PAI vitality index evaluation, respiratory training and so on. In addition, it also has the functions of caring for women's health, recording and reminding the physiological period and ovulation period, which can bring more intimate services to users.
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