Hello, dear, the heartbeat is not displayed, because the wearable device on the wrist will shake during exercise, which will affect the quality of the heart rate measurement signal. Different types of sports produce different noise signals. By selecting the corresponding movement type, the algorithm can better process it, improve the signal quality and ensure more accurate heart rate measurement. Therefore, it is suggested that you choose the correct exercise type at the beginning of exercise, so as to obtain more accurate heart rate data during exercise. You may sweat a lot during exercise, the wearable device slides up and down, and the sweat blocks the heart rate monitoring sensor, which may lead to deviation in heart rate measurement. Please dry the sweat on your wrist and the wearable device, keep the back of the wearable device clean and dry, and fasten it after there is no foreign body covering it. If the pressure value is not displayed, you can turn on the health monitoring on the Huawei Health App device page and turn on the automatic pressure detection switch. When using it for the first time, please perform pressure calibration in Huawei Health App and fill in the pressure calibration questionnaire. In the exercise state, the bracelet/watch does not provide stress data. When you keep quiet for a long time, the bracelet/watch will automatically carry out pressure detection.
How does mi band measure his heart rate? Why does it always show failure?
The heart rate can be measured according to the following operations. There are several reasons for the failure, as follows.
The correct way to wear Mi band:
1. Wear it with proper tightness, and it is impossible to accurately measure the heart rate by bypassing the wrist, wearing it too loosely or wearing it too tightly.
2. After wearing it, touch the button 2 of mi band to enter the heart rate measurement. Please keep still when measuring. The heart on the bracelet screen flashes, indicating that you are measuring.
3. Wait a moment, and the measurement results will appear on the display screen of Xiaomi bracelet 2.
Reasons for failure of heart rate measurement:
1. Xiaomi's products are always labeled as cost-effective, including Xiaomi bracelet 2, which is selling well now. This bracelet has realized most functions that the first generation bracelet didn't have, such as time display, step view, heart rate monitoring, sleep monitoring and so on.
2. It may be that the user's wrist and body are moving when testing the heart rate change, which may easily lead to the change of the detection range of the bracelet and the unrecognizable situation.
reference data
Uc headlines. Uc headlines [reference time 20 18- 1-24]
Computer Pepsi network. Computer Pepsi Network [reference time 20 18- 1-24]
Is it accurate to measure heart rate and blood pressure with smart bracelet?
Principle of measuring heart rate and blood pressure with smart bracelet
Generally speaking, the principle of heart rate monitoring is usually divided into three types: one is photoelectric transmission measurement, and the principle is that the sensor that the bracelet contacts with the skin will emit a beam of light to hit the skin to measure the reflected/transmitted light. Because blood can absorb light with a specific wavelength, every time the heart pumps blood, this wavelength will be absorbed in large quantities, thus determining the heartbeat. But the disadvantage is that it consumes a lot of electricity and is disturbed by ambient light. At present, the function of monitoring heart rate of smart bracelets or watches on the market mostly adopts photoelectric transmission measurement.
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.
How accurate is the heart rate measured by the bracelet?
In terms of accuracy, in fact, as I mentioned earlier, the photoelectric transmission measurement methods adopted by most hand rings are not very accurate and are easily disturbed by the external environment. For individuals, the importance of bracelet heart rate monitoring lies in continuous monitoring. Even if the absolute value is not accurate, some values can still be found by analyzing the relative change trend.
Can the bracelet realize real-time dynamic ECG measurement?
One-handed bracelet can't measure ECG, because the simplest one-way ECG also needs at least one electrode on the left and right sides of the human body. Of course, technically speaking, ECG bracelet is completely feasible, but users may need to wear bracelets with both hands. In fact, starting from life, we don't need to see our ECG in real time, but we can see the change of heart rate over a period of time.
Is the bracelet that can measure heart rate worth it?
With the rise of smart wearable devices, more and more manufacturers have joined the melee in the smart wearable market. The first thing to start is the price war. The low threshold of the bracelet will naturally attract the attention of some users. In the face of some products that can detect heart rate for less than 100 yuan, I believe that the first reaction of many friends is so cheap, whether it is reliable or not, and whether it is worth buying.
As for the reliability, as I mentioned before, it is not very accurate to measure the heart rate with the bracelet itself. Its significance is only to let people know the changing trend of their own state, and many bracelets are only practical here, and there is not much extension. So if we really want to discuss whether it is worth buying, I think if you just want to experience it or use it as a toy, it is ok to buy one at a low price. If you really expect it to help you treat or prevent diseases, forget it.
At this stage, even if the smart bracelet has a bright future, it must be said that the appearance of the heart rate monitoring function is far greater than the actual effect. In vernacular Chinese, what is the use of ordinary users knowing their heart rate? There are no doctors around to provide real-time advice, and bracelets often can't provide some constructive guidance for users. Looking at the heart rate on the mobile phone, all we can know may be a set of numbers and a state diagram.
In fact, smart bracelet manufacturers should pay more attention to the ecological environment. If the smart bracelet APP can integrate some medical platforms, such as customizing private doctors, it will be a benefit project. I believe many people will pay for this. Unfortunately, it takes a lot of resources to do this, and it takes a long time to really implement it. Of course, I'm just offering an idea. What do you expect from the auxiliary health function of smart devices?
Smart bracelet heart rate scam
Smart bracelet heart rate scam
Smart bracelet heart rate scam, smart bracelet is a wearable smart device. Most smart bracelets on the market focus on detecting heart rate, so many people will choose to wear smart bracelets during exercise in order to better detect their own sports. Let's learn about the smart bracelet heart rate scam.
Smart bracelet heart rate scam 1
Working principle of smart bracelet
The early sports bracelet was only equipped with simple acceleration sensor and Bluetooth function, so its function was simply to count steps, and then connected to the smart phone to check the amount of exercise through the application on the smart phone.
Later, with the development of technology, smart bracelets and mobile apps can realize more complex applications-monitoring heart rate, sleep, exercise state evaluation and a series of health-related functions.
Especially with the appearance of heart rate monitoring, fitness experts can know their heart rate changes anytime and anywhere during running, so as to adjust the fitness rhythm scientifically.
If you find that the bracelet advertised by the merchant has other outrageous functions besides the above monitoring functions such as heart rate and exercise, run quickly and pay the IQ tax appropriately.
How does the smart bracelet detect our heart rate?
Smart watches and smart bracelets that are common in our daily life generally use PPG (Photoelectric Volume Pulse Wave Recording) to monitor heart rate and blood oxygen.
This is a photoelectric detection method. Firstly, the LED light source is used to generate light pulses, which are injected into human skin tissue at a certain angle. The photosensitive element at the receiving end converts the optical signal reflected from the skin into an electrical signal, and then the heart rate is obtained through certain signal processing.
Because the blood in our skin tissue changes periodically with the pulse, and their absorption of incident light also changes periodically with the pulse, the intensity of the photoelectric signal received by the receiving end of the smart bracelet will change with the pulse. Through the digital signal processing algorithm, we can calculate the pulse period and then calculate the heart rate.
However, this method is not foolproof.
For example, many people find that the heart rate measured by the exercise bracelet is only 80 after high-intensity exercise. This is mainly because when we wear the bracelet, the position of the photoelectric sensor and the close contact with the skin will change with human activities, which leads to inaccurate pulse rate measurement.
For another example, someone put a sports bracelet on a paper towel before, and the result can actually measure the heart rate! Why is this? In fact, the smart bracelet can't identify whether it is a living body.
When it touches the paper towel, it assumes that it is your wrist, and then it starts to work: emitting a beam of light-collecting reflection information-algorithmic processing. Therefore, even if the toilet paper has no heartbeat, when the green light emitted by the emitter is placed on the surface of the toilet paper, there will still be light reflection, and the final result is the result received by the receiver after the light reflection on the surface of the toilet paper.
However, it is believed that with the development of technology, smart wearable devices will continue to improve, and the physical parameters that smart wearable devices can detect will gradually increase, thus providing more and more accurate information for our health monitoring.
It should be pointed out that the brands and prices of smart bracelets and smart watches are very different, and the accuracy of heart rate detection and sleep quality monitoring of different wearable devices is also very different. At present, most intelligent expert rings estimate these physiological parameters by digital algorithm, and the accuracy is still far from that of professional equipment. Therefore, people with health problems or high requirements for the accuracy of pulse blood pressure data are advised to use professional medical devices for measurement.
In addition, the function of the smart bracelet is amazing, after all, it is just a tool. Small hand rings can greatly facilitate our lives, but we still have to choose the right products according to our own needs.
Smart bracelet heart rate scam 2
First, is it reliable to measure the heart rate with a smart bracelet? Let industry experts reveal the secret for you.
The first one: the principle of PPG photoelectric plethysmography.
Simply put, reflection is to use the pulse change of light transmittance in blood to convert it into an electrical signal, which corresponds to the heart rate.
▲ representative product: FitbitchargeHRSurge
When a light beam with a certain wavelength irradiates the skin surface of the fingertip, the light beam will be transmitted to the photoelectric receiver through transmission or reflection, and the light intensity detected by the detector will be weakened due to the absorption and attenuation of the skin muscles and blood of the fingertip. Among them, the absorption of light by skin and muscle tissue remains unchanged throughout the blood circulation, while the blood volume in the skin changes pulsatively under the action of the heart.
When the heart contracts, the peripheral blood volume is the largest, the light absorption is the largest, and the detected light intensity is the smallest. When the heart is diastolic, on the contrary, the detected light intensity is the largest, which makes the light intensity received by the receiver fluctuate accordingly.
Why do you often see green LEDs?
Because in front of red liquid and blood, the absorption rate of green light is the largest, and the data judgment is more accurate.
When the user's heart beats, more blood will flow through the user's wrist and absorb more green light. During the interval of heart beating, the blood flow decreases, resulting in a decrease in the absorption of green light.
For example, suppose that the luminous value of the bracelet is 100, the absorption of skin and muscle tissue is constant 10, and the total absorption of blood is100-10 * 2-15 = 65. After reflection, arterial blood comes over.
I don't know if PPG is understood in this way.
Its principle determines its shortcomings. What should I do if there is a lot of sweat directly on the bracelet and skin? Then the value will be inaccurate.
If your value changes like this, 65-50-65-50-65-50-66-51-62-50-65 and so on. This will also force the machine.
To sum up:
This method is more accurate for measuring resting pulse and normal regular exercise (running, etc.). ), but for irregular sports, such as football and badminton, the assumed values will jump around and the accuracy will drop slightly. But there are also several differences in values. For non-professionals, I think it should be enough.
The second type: ECG signal measurement, similar to ECG (electrocardiogram)
Simply put, this is the electrocardiogram you did in the hospital, which is actually a bit similar. The difference is that the hospital needs to add electrodes to the heart, feet and wrists, and needs to measure more data, while the wrist does not need so much data, and the heart rate is enough.
Simply put:
The tissues and body fluids around the heart can conduct electricity, so the human body can be regarded as a three-dimensional volume conductor: length, width and thickness. The heart is like a power source, and the sum of action potential changes of countless myocardial cells can be conducted and reflected to the body surface. There are potential differences between many points on the body surface, and many points are equipotential, and there is no potential difference. Through the collected electrode changes and algorithm processing, many values can be restored, among which the heart rate value can be restored.
Every heartbeat, there will be tiny electrode changes on the surface of human body, and these electrode changes can be captured, and then the' frequency' of heartbeat can be restored by algorithm. As far as I know, in the bracelet, it seems that jawbongUP3 adopts ECG measurement technology, and most of the others are photoelectric technology.
As a new product in the 2nd/Kloc-0th century, smart wearable products are mainly used in this field because of their specific usage scenarios and wearing requirements. At present, photoelectric volume pulse wave tracking, referred to as photoelectric method, ECG signal method, pressure oscillation method, image signal analysis method, etc.
For the heart rate area, ECG measurement is generally used to detect the changes of body surface electrodes and restore the heart rate value.
Second, how to realize heart rate monitoring?
1, photoelectric method
Simply put, this method of measuring heart rate is based on the principle of light absorption by matter. Blood vessels are illuminated by the green LED lamp of smart wearable device with photosensitive photodiode for a period of time. Because blood is red, it can reflect red light and absorb green light. When the heart beats, the blood flow increases and the absorption of green light increases. When the heart is in the interval of beating, the blood flow will decrease and the absorbed green light will also decrease. Therefore, the heart rate can be measured according to the absorbance of blood.
Specifically, when a light beam with a certain wavelength irradiates the skin surface, the light beam will be transmitted to the photoelectric receiver by transmission or reflection. In this process, due to the attenuation of skin muscle and blood absorption, the light intensity monitored by the detector will be weakened. Among them, the reflection of human skin, bones, meat and fat. It is a fixed value for light, while capillaries, arteries and veins become larger and smaller with the pulse volume under the action of the heart.
When the heart contracts, the peripheral blood volume is the largest, the light absorption is also the largest, and the detected light intensity is the smallest; When the heart is diastolic, on the contrary, the detected light intensity is the largest, which makes the light intensity received by the receiver fluctuate accordingly.
Most smart watches use photoelectric method to monitor heart rate, and its obvious feature is that the sensor is equipped with green LED light.
There are many kinds of photoelectric sensors with this measuring principle. According to the different receiving positions of optical signals, photoelectric methods can be divided into transmission and reflection.
1. transmission photoelectric method
Transmission photoelectric method means that the emitter and detector on the wearable device are located on both sides of the tested part (usually fixed by clips). Incident light passes through the skin and enters deep tissues. In addition to being absorbed by skin, muscles, blood, bones, etc. The rest of the light is transmitted and perceived by the photosensitive receiver. According to its principle, this method is suitable for measuring tissues close to both sides of human body, such as earlobes, fingers and toes. Representative smart wearable products include ear clip heart rate monitor and nail oximeter.
Smart wearable products using transmission photoelectric mode are usually fixed with clips.
The products of this monitoring method usually adopt the structure of sealed cassette in appearance, which can well reduce the interference of external light, thus improving the measurement accuracy and stability. Because of its high signal-to-noise ratio and stable signal, besides measuring heart rate, many cardiovascular physiological information such as heart function and blood flow can be analyzed by waveform. The disadvantage is that it is not suitable for smart bracelets and smart watches, and products coated on earlobes, toes and other parts will feel uncomfortable to wear.
2. Reflection photoelectric method
Contrary to the transmission photoelectric method, in the reflection photoelectric method, the emitter and detector on the wearable device are located on the same side of the measured part, and mainly measure the reflected light. The advantage of this method to measure heart rate is very simple, and the requirements for measuring parts are also very low. As long as the tissue is smooth and there is little subcutaneous fat, it can be measured almost anywhere, such as forehead and wrist.
Therefore, most wearable devices such as smart bracelets and smart watches use this method to measure heart rate. But also in the form of smart bracelet or smart watch, which perfectly solves the dual requirements of transmission photoelectric method for center rate monitoring and wearing comfort.
However, although the reflective photoelectric method performs well in a stable state, when the device is worn at the end of the wrist, it will swing up and down like a pendulum with the user's walking or irregular movement, and the centrifugal force will greatly change the blood volume; When systolic pressure and centrifugal force interact in blood, it is more difficult to distinguish the amount of blood in blood vessels. Therefore, the accuracy of heart rate data may be reduced. In addition, the tightness of wearable devices and the blood flow of human skin will also affect the monitoring accuracy.
2. ECG signal method
Electrocardiographic signal method is actually the most accurate method to measure heart rate commonly used in medical grade. In each cardiac cycle, the heart is excited by pacemakers, atria and ventricles, accompanied by the changes of action potentials of countless myocardial cells. These bioelectrical changes are called ECG, and the heart rate can be detected through the periodic changes of ECG. In addition to heart rate, ECG can also provide information including cardiac insufficiency, heart disease, recovery of cardiac function, physiological and psychological stress of patients.
For smart wearable devices, the sensor can judge the user's heart rate by measuring the electrical signal of myocardial contraction. The principle is similar to ECG, and the accuracy of this method is very high. But 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 smart wearable products using this measurement method are rare.
Electrocardiogram lead system.
3. Pressure oscillation method and image signal analysis method.
Pressure oscillation method is mainly used for electronic sphygmomanometer. The cuff of the sphygmomanometer exerts pressure on the arm, and the pulse amplitude of arterial blood vessels is detected by the membrane pressure sensor for AD conversion, thus measuring blood pressure and pulse rate (the heart rate is calculated according to how many pulse waves there are in a certain period of time). Image signal analysis mainly uses facial images to estimate heart rate.
Because when the heart beats, the color of the face will change slightly, and the chest and shoulders will also move slightly, so the heart rate and breathing frequency can be estimated by the collected images.
Vital-Radio introduced by MIT is a kind of Wi-Fi signal sent by router. When the signal meets people or objects around it, it will bounce back immediately. Through a special algorithm, the reflection velocity of each signal can be calculated, so as to judge whether there is a living body. If it is alive, this product will record people's heart rate and breathing frequency.
These two methods have higher requirements for users, which are limited to the relatively static human body. If the methods are not appropriate, the results will be much worse, and even the measurement results of some patients with cardiovascular diseases are not accurate. Therefore, there are very few products in the field of smart wearable devices that use these two methods to measure heart rate.
Smart bracelet heart rate scam 3
Can the smart bracelet also measure blood pressure? Is it reliable?
Nowadays, many smart bracelets have the function of measuring blood pressure, but this so-called blood pressure measurement is only a rough estimate, not the real pressure on the blood vessel wall of human body (that is, blood pressure), so compared with the heart rate detection with excellent publicity function, the blood pressure detection function may be slightly inferior.
Is real-time sleep monitoring reliable? Sleep detection is also an important advantage of smart bracelets. Through the sensor inside the bracelet, you can feel the skin. When people are asleep, analyze an action, posture, sleep time and amplitude, analyze deep sleep and shallow sleep, and then get the results according to the data.
For example, many smart bracelets monitor sleep by actually analyzing whether your smart bracelet moves with time, size and frequency. For example, if you lie still for a long time, the smart bracelet may default that you are asleep, but you are not.
There used to be some smart bracelets. When you realize that you are going to sleep, you must press the sleep button before going to sleep. Many people may be tired. But after pressing the sleep button, I woke up immediately, but I couldn't sleep. From this perspective, smart bracelets are not so "smart".
Does the smart bracelet belong to medical devices? As the main concern is health, many people ask whether the smart bracelet is a medical device. After all, the state's approval and management of medical devices are quite strict. If the smart bracelet is an approved medical device, then you can buy it with confidence!
Facts have proved that the current smart bracelet is still very reliable in measuring heart rate, and the error will not be too big. Although the detected data is for reference only and cannot be used as a basis for diagnosis, it does not affect the accuracy of the smart bracelet. Therefore, if you or your family are very concerned about the heart and heart rate, it would be a good choice to buy a smart bracelet for testing.
Wearable devices, such as smart bracelets and watches, generally have the function of heart rate detection to monitor people's health. What happened to the inaccurate heart rate measurement after spitting mi band 4?
Mi band 4 has a big heart rate error?
1. Please make sure that the back of the bracelet is clean, dry and free of foreign objects. Excessive sweating during exercise causes the watch to slip, and sweat blocks the light path, which may lead to inaccurate heart rate measurement. Please dry your sweat before putting it on.
2. It is recommended to use a soft rubber strap, so that the device can fit the wrist better and the monitored data is more accurate.
3. People's heart rate is not stable, even at rest, the heart rate data will fluctuate in a small range. After strenuous exercise, the heart rate value will jump greatly after continuous measurement, which is due to the rapid decline of human heart rate itself, which is also a normal phenomenon. When you stand, sit, eat and drink, the range of heart rate data will increase accordingly.
4. Exercise regularly (such as running, walking, cycling, etc.). ) It is easier to accurately measure the heart rate, but irregular exercise (such as playing ball and moving freely) is not necessary, nor is wrist strength exercise (such as weightlifting).
5. It may also be caused by hardware failure. It is suggested that Xiaomi Service Center check before and after.
This paper takes mi band 4 as an example for application.