With the popularity of wearable devices and home health monitoring devices gradually making their way into millions of homes, the key technology of these devices, blood pressure sensors, is playing an increasingly important role in the field of health monitoring. From home blood pressure monitors to smart watches, built-in blood pressure sensor chips and modules allow users to monitor their blood pressure anytime, anywhere, and help detect potential health problems at an early stage. In this paper, we will discuss the principles, types, and applications of blood pressure sensors in wearable devices and medical equipment, with a focus on the design and operation of digital blood pressure sensors, small blood pressure sensors, and built-in blood pressure sensor modules.
- Working principle of blood pressure sensor
- Wearable blood pressure sensor
- Blood pressure sensor chips and modules
- Application of blood pressure sensors in digital devices
- Pressure changes and sensor sensitivity
- Conclusion
1.Working Principle of Blood Pressure Sensors
The core function of a blood pressure sensor is to convert human blood pressure signals (physical signals) into electrical signals. This conversion process is usually based on the piezoresistive or capacitive effect. Simply put, when human blood pressure is applied to the surface of the sensor, the sensor diaphragm is deformed slightly, and this physical change is converted into a measurable signal by a specially designed circuit. This physical change is converted into a measurable signal by a specially designed circuit. As the blood pressure changes, the output signal from the sensor changes as well.
While traditional mechanical pressure sensors rely on elastically deformed materials, MEMS (micro-electro-mechanical systems) technology has dramatically improved the performance of sensors. Compared to traditional mechanical sensors, MEMS technology produces sensors that are smaller, more sensitive, and consume significantly less power and cost. A typical MEMS blood pressure sensor may be larger than a grain of rice and can be integrated into a variety of electronic devices such as bracelets, watches and other wearable devices.
Piezoresistive blood pressure sensors are one of the more widely used technologies today, and are based on the Whiston bridge principle. It is based on the Whiston bridge principle. Simply understood, when pressure is applied to the sensor diaphragm, the pressure-sensitive resistance on the diaphragm will be changed, and this change in resistance will result in a change in the output voltage of the bridge, which will reflect the change in pressure, and in turn, result in a reading of the blood pressure.
In the medical field, when selecting a blood pressure sensor, the commonly used range of 40 kPa is particularly suitable for use in electronic blood pressure monitors. In this pressure range, the sensor needs to be very accurate, usually around 0.5% FS (full scale), which means that the measurement error is very small to ensure that the user receives accurate blood pressure data.
Two important parameters are pressure range and sensitivity. The sensor required for an ambulatory blood pressure monitor should be able to measure a pressure of 40 kPa (approximately 300 mmHg). Why? Because 300 mmHg is the maximum measurement standard for most blood pressure monitors, and measurements above this pressure can introduce measurement errors.
MEMS sensors can easily realize such pressure measurement. For example, for home blood pressure monitors, WFsensors has developed a MEMS sensor with a pressure range of 40kPa, specifically for use in electronic blood pressure monitors. The sensor is not only highly sensitive, but also maintains a non-linear error of ±0.0736% Wearable Blood Pressure Sensors
Wearable blood pressure sensors have become an important field with the popularity of wearable devices such as smart watches and health bracelets. These sensors must be small, low-power, accurate and reliable. Unlike traditional blood pressure monitors, wearable blood pressure sensors typically provide 24/7 health data by continuously monitoring the user’s blood pressure.
These sensors infer the user’s blood pressure through a mīkini paʻi module built into the bracelet or watch, combined with a software algorithm. For example, some smartwatches use a combination of optical sensing technology and pressure sensors to detect changes in the user’s blood flow and analyze blood pressure levels.
In the future, we may see more of these applications that not only monitor blood pressure at home, but also provide real-time feedback on health status to prevent potential cardiovascular disease.
2. Wearable Blood Pressure Sensors
Wearable devices have been developing rapidly in recent years. For example, smart bracelets, smart watches, and even shoes have begun to integrate blood pressure sensor chips. The blood pressure sensor modules in these devices are usually very small to fit the size of the device. However, while reducing the size of the device, there is also a need to ensure accuracy, sensitivity and low power consumption. These wearable devices typically monitor a user’s blood pressure in real time to help them manage their daily health data.
Typical built-in blood pressure sensors convert the pressure signal into a digital signal through a microcircuit, which is then transmitted to a cell phone or other device via wireless technology such as Bluetooth or WiFi. Such sensors are often equipped with a low-power design that allows them to operate for extended periods of time, allowing the range and resolution of the sensor to be further optimized, especially in lithium battery-powered wearable devices.
3. Blood Pressure Sensor Chip and Module
Wearable devices have been developing rapidly in recent years. For example, smart bracelets, smart watches, and even shoes have begun to integrate blood pressure sensor chips. ʻO ka blood pressure sensor modules in these devices are usually very small to fit the size of the device. However, while reducing the size of the device, there is also a need to ensure accuracy, sensitivity and low power consumption. These wearable devices typically monitor a user’s blood pressure in real time to help them manage their daily health data.
Typical built-in blood pressure sensors convert the pressure signal into a digital signal through a microcircuit, which is then transmitted to a cell phone or other device via wireless technology such as Bluetooth or WiFi. Such sensors are often equipped with a low-power design that allows them to operate for extended periods of time, allowing the range and resolution of the sensor to be further optimized, especially in lithium battery-powered wearable devices.
4.Blood Pressure Sensor Applications in Digital Devices
Digital blood pressure sensors use analog-to-digital conversion (ADC) technology to convert analog pressure signals into digital signals for easy data interaction with other digital systems. These sensors can be easily integrated into a wide range of devices, calibrated, adjusted and stored via software, and even analyzed and managed in the cloud. This digitization not only reduces interference in the analog signal transmission, but also improves overall system accuracy and stability.
This highly integrated module is ideal for devices such as home blood pressure monitors and wrist blood pressure monitors. These devices can record and transmit the user’s blood pressure data in real time through the built-in sensors, helping users and doctors to better manage their health.
5. Pressure Changes and Sensitivity of Sensors
Blood pressure sensors must be highly sensitive and able to detect subtle pressure changes in order to accurately monitor blood pressure. Especially in the case of large pressure changes, the sensor’s nonlinear error cannot exceed ±0.1%, otherwise it will affect the accuracy of the final measurement results. Designers need to conduct extensive simulation tests when selecting diaphragm thickness, resistance and stress distribution.
For example, WFsensors’ research has shown that the sensitivity and linearity of the sensor can be significantly improved by choosing the thickness of the pressure-sensitive film appropriately (e.g., 15 μm). Kahi mea hou aʻe, the use of advanced MEMS processes can ensure the stability and reliability of the sensors over a long period of time.
6. Conclusion
In the future, as MEMS technology continues to advance, blood pressure sensors will become smarter, more accurate, and widely used in wearable health devices. We can imagine that future blood pressure sensors will not only be used in bracelets or watches, but also in other medical devices, and may even develop devices that monitor blood pressure without contact, through optical or ultrasound technologies.
For researchers, the challenge remains to further reduce the size of the sensor, lower production costs and improve integration while maintaining high accuracy. At the same time, it is expected that more complex sensor arrays can be used to obtain more comprehensive physiological parameter data, which will further promote the advancement of personal health management.
In the future, as MEMS technology continues to advance, blood pressure sensors will become smarter, more accurate, and widely used in wearable health devices. We can imagine that future blood pressure sensors will not only be used in bracelets or watches, but also in other medical devices, and may even develop devices that monitor blood pressure without contact, through optical or ultrasound technologies.
For researchers, the challenge remains to further reduce the size of the sensor, lower production costs and improve integration while maintaining high accuracy. At the same time, it is expected that more complex sensor arrays can be used to obtain more comprehensive physiological parameter data, which will further promote the advancement of personal health management.
References：
1.McMasters Consulting, “MEMS Pressure Sensor Application and Market Outlook Analysis,” 2023.
2.Wu, M., & Wang, H. (2020). “The Development and Application of MEMS Pressure Sensors in Medical Equipment”, Journal of Microelectromechanical Systems.
3. Wang, Z., & Li, Y. (2022). “Pressure Sensor Chip Design and Fabrication for Wearable Devices”, Sensors and Actuators A: Physical.
This article leads you to an in-depth understanding of how blood pressure sensors work, application scenarios, and technical challenges.MEMS pressure sensors are undoubtedly a major advancement in the field of e-health, providing an accurate and convenient solution for daily blood pressure monitoring. If you are interested in this type of technology, we recommend you to stay tuned to this field of technology development and market trends.
