How does the radar detect vital signs such as non-contact respiration, heart rate and other vital signs, and how does the radar judge dynamic or static? Vital signs parameters are important indicators to measure whether people are healthy, and real-time detection of vital signs signals has high research value. The current vital signs detection equipment on the market is not only difficult to meet the needs of general users in terms of price, but the equipment itself is also restricted by the cable connection, and most of the traditional conventional monitoring methods require the sensor to contact the human body, such as: Electrocardiogram (ECG): Photoelectric volume image blood oxygen sensor (PPG) and pressure-sensitive pulse sensor, etc.
Based on microwave radar, it does not need to be in contact with the human body, is not easily affected by the environment, has the advantages of good penetration, strong anti-interference ability, etc., non-contact, small, and portable solution for health monitoring and other fields Cardiopulmonary activity monitoring realizes real-time health monitoring of home and outdoor environment, and realizes portable medical treatment. Microwave Doppler bio-radar is used for clinical detection, medical detection and sleep monitoring of patients with sleep disordered breathing, and baby care has a broad application space.
With the development and popularization of smart terminals, signal processing and feedback based on mobile platforms have begun to be widely used in medical signal processing. A radar sensor with vital signs information is designed. The information collected by the radar is transmitted to the smart mobile terminal through the WiFi module. The mobile terminal is used to replace the computer or embedded system to process the digital signal and perform heartbeat and breathing in real time. , Display and storage, and established a set of vital signs monitoring system.
In practical applications, the radar uses the emitted electromagnetic waves of different frequencies and wavelengths to judge targets. The transmitting device of the radar device transmits electromagnetic wave energy to a certain spatial direction through the antenna, and the electromagnetic wave reflected by the object in this direction; the radar antenna receives this reflected wave and sends it to the receiving device for processing. Obtain information about the distance from the target object to the radar, the rate of change of the distance, or the radial velocity, azimuth, height and other information.
In a static state, the reflected wavelength changes with the changes in the parameters of the object. The wavelength is fixed. When encountering a moving object, the wavelength will change and affect the direction of the moving object. At a long distance from the transmitting device, the reflected wave has a longer wavelength and higher frequency than the wave source; when it is close to the transmitting device, the reflected wave has a shorter wavelength and lower frequency.
The Ferry Smart microwave radar module FR58L4M32-7060D(A) is an example. It uses the Doppler principle to emit high-frequency electromagnetic waves from the antenna, and receives the processed reflected waves to determine the motion of the covered object, thereby judging the Exercise, give the corresponding electrical signal. This is a small and complete radar system that integrates a transceiver antenna in a very small area and has the characteristics of low power consumption. The system can perceive the motion state of objects in a closed space, and can accurately measure the distance between objects.
Using Ferry Smart microwave radar to achieve indoor scene vital signs monitoring program, the program can achieve all-weather, contactless, non-contact, with real-time monitoring, real-time feedback and other vital signs monitoring functions, with real-time monitoring, real-time feedback and other characteristics. In addition to the long measurement distance, this method has more advantages in accuracy and precision. It can detect the human body's micro-motion and breathing signals, and realize the detection of human body motion and static state. The real realization has induction, and it is also widely used in smart lighting, smart security, smart sensor switches, smart bathroom, smart home, etc. Areas.
Compared with the infrared module, the microwave radar module has a long sensing distance and a long angle. No dead zone, lens and lens aging problems are not affected by temperature, humidity, airflow, dust, noise, brightness, etc. MCU integrates a high-performance 32-bit processor, can do a wealth of algorithms, has strong scalability, and is suitable for scenarios that meet high-performance requirements. The radar sensor can be configured by a single-chip microcomputer, and its sensing distance can reach 7 meters. The actual sensing distance can be flexibly adjusted according to needs. If the use environment is a relatively narrow space, the sensing distance and angle will also change accordingly.
The presence of a human body can be detected within a set distance. In smart buildings, from screens and displays, to lighting and safety equipment, smart homes, and all devices within the range of smart buildings, it is possible to determine whether living bodies are close enough and trigger operations. Even if the user is in a static state, the Ferry Smart presence detection solution can also detect and react to the micro movements of breathing. Due to this micro-motion detection function, the solution is very suitable for direct interaction between the user and the device. In this way, the user does not need to wave his hand in front of the sensor for the device to react.
Precautions:
1. Avoid installing metal accessories or shells, metal will block the microwave and affect the use effect;
2. The surface of the antenna should be protected from the coverage of high-current circuits, which may cause interference;
3. The sensor output current is very weak, and the driving current is too large to cause false alarms. The isolated driving method of driving the load can be adopted, and the output port status can be read by the OUT pin;
4. Please use a power supply with a small ripple for power supply, especially for low-frequency ripple dry-type sensors. It is recommended that the power supply capacitance be greater than 100uF;
5. It is recommended that the sensor installation distance is greater than 1.5 meters.
Ferry Smart is promoting the domestic low-cost alternative to non-contact respiration, heart rate and other vital signs detection radar, it is worth paying attention to!
