Now people are paying more and more attention to their health, so smart wearable devices have sprung up. What smart watches, smart bracelets abound. Then in addition to the information push on some mobile phones, the most important function of these devices is health detection. Heart rate, oxygen saturation, electrocardiogram and other physiological indicators. Or some kind of function to detect how many calories you exercise. So how did they do it on such a small screen device?
First of all, let's talk about "heart rate detection"
We can basically find that when the device detects the heartbeat, most of them will have a green light at the bottom of the device. Yes, it is this crucial green light, which is the key factor to test your physical condition. Isn't there a song that says "You are a light, so beautiful"!
In fact, the principle of detecting heartbeat by luminescence is a technique of measuring pulse in an optical way, which is called "PGG photoelectric volume pulse plethysmography". To put it bluntly, just like radar, the equipment has two sets of transmitting and receiving devices, which emit light, and when it is reflected by the human body, the receiver receives the reflected light, and the results are obtained after analysis.
To make matters more complicated, when a light beam with a certain wavelength irradiates the skin surface, skin, muscles and blood will absorb part of the light, while red blood will be more inclined to reflect part of the light. Because when the heart contracts and relaxes, the blood and velocity in the blood vessels are different, so the colors of the light they reflect will be different. After receiving this series of reflected light data of different colors, the sensor uses a certain algorithm to calculate the heart rate.
This is equivalent to a process of "optical-electrical-digital signal".
Is it useful to use smart bracelet for ECG monitoring? It should be a smart bracelet to measure heart rate. Whether it is useful or not depends mainly on what you do. If you only use it as a reference to guide your exercise, I personally think it is still useful. With the reference heart rate during exercise, aerobic and anaerobic exercise can be basically controlled.
When the smart bracelet measures the heart rate, it is theoretically accurate to use the photoelectric sensor to detect the blood flow algorithm of the surface skin and calculate the heart rate. In practical application, small errors are often caused by wearing details, and the error range is acceptable. The effect of exercise will be more and more obvious, especially for fat-reducing exercise, so that you can achieve the appropriate exercise effect at an effective heart rate.
The smart bracelet measures the heart rate by a green light that shines on your skin, and then the sensor absorbs the emitted light to judge the blood flow under your skin through different emissivity. So if it doesn't fit closely, it's easy to make errors ~ there are sensors and software algorithms of data, all of which are different, more or less different, but not outrageous, and they are ok in daily life.
Another method is to test the ECG signal. The sensor of the bracelet can judge the user's heart rate by measuring the electrical signal of myocardial contraction. The principle is similar to electrocardiogram. The disadvantage is that the circuit is complex, takes up a lot of PCB space and is vulnerable to electromagnetic interference. At the same time, the sensor must be close to the skin and placed in a relatively fixed position, so it is difficult for a bracelet to adopt this measurement method.
In addition, there is vibration measurement, and the product has only recently been produced. Because every heartbeat will cause the vibration of the body, this vibration can be captured by high-precision sensors, and then the heartbeat can be obtained through signal processing. Generally speaking, products such as smart cushions or smart massagers will adopt this measurement method, and there are relatively few bracelets.
What is the use of smart bracelets?
Entry-level function of smart bracelet
1, record sports data.
FashionComm Le Kang Sports Bracelet believes that for fitness enthusiasts, the more detailed the sports data recorded by smart bracelets, the better. But in fact, many sports bracelets can only roughly record steps, distances and calories, and can't distinguish different sports types. Some sports tracking bracelets can automatically monitor different types of sports, such as walking, cycling and walking, but the monitoring effect may not be satisfactory.
In order to improve the stickiness of the bracelet, the brand of the motion detection bracelet is different. The common practice is to convert sports achievements into points that can be used for consumption and activity points. Some Bluetooth sports bracelets can also exchange sports data for props and gold coins in daily cool running games, which is quite attractive for cool running enthusiasts.
Step 2 record sleep data
FashionComm Le Kang sleep bracelet thinks that sleep monitoring bracelet should include different sleep modes such as deep sleep, light sleep and interruption, but most bracelets can only record sleep data, and most of them have no specific sleep monitoring analysis.
3. Silent alarm clock
In the early days, many bracelets with alarm clocks did not have this function, but now most smart bracelets come standard with this function. Smart bracelet brands have designed vibration alarm clocks. Usually, users need an alarm clock to wake themselves up quietly, and they don't want the alarm clock on their mobile phones to be too noisy and affect others. In addition, users hope to sleep more efficiently without affecting their daily work and life after entering shallow sleep.
Advanced features of smart bracelet
1, exercise guidance
Sports guidance is also a function gradually evolved from sports fitness bracelet, which is equivalent to a simple fitness coach. Users can choose a variety of preset exercise plans and steps, and the smart bracelet will guide users step by step.
2. Heart rate monitoring
With the increasing demand of users for fitness bracelets, users are no longer satisfied with simply recording steps and calorie consumption. The addition of heart rate monitoring function can enable users to achieve healthier fitness goals. At present, there are more and more heart rate monitoring bracelets based on exercise. It is foreseeable that the heart rate monitoring function may gradually become the standard of sports bracelets.
3. Social reminders
After some social smart bracelets are connected with smart phones, they can display telephone, SMS, WeChat, email and other notifications, so that users no longer need to light up their mobile phone screens frequently to avoid missing information. Just look at the smart bracelet, which can not only be less abrupt, but also save electricity and improve the battery life of the mobile phone. For example, Microsoft Band can basically display notifications from mobile phones, and L 1 1, a better smart bracelet of Leyuan Digital FashionComm, a well-known smart wearable device brand, will also add corresponding social reminder functions.
Step 4 communicate
There are two ways to socialize with smart bracelets. One way to socialize is to make friends with each other. It would be interesting if this function can cross the brand barrier. Another setting of social bracelet is sports competition, and users of smart bracelet brand can have PK. After WeChat supports intelligent hardware access, cross-brand PK may also become a reality.
Step 5 answer the phone
Answering the phone is a standard for smart watches. You don't need to take out your mobile phone from your pocket to answer the phone, which can be of great use in extremely crowded places. At present, smart bracelets with telephone answering function are rare.
6. Remote control
With the support of software, remote control can be realized through smart bracelets. Because it involves multi-brand collaboration, this feature has not yet appeared on the smart bracelet.
7. Time display
The biggest difference between a smart watch and a smart bracelet is that a watch should naturally display the time, while a smart bracelet is not. In order to attract smart watch users who value the time function, some smart bracelets can also display the date and time.