Physical detection, dynamic heart rate sensor comparable to MIO!

Photocoupler

Heart rate is an important parameter reflecting the function of the human circulatory system. Regular measurement of heart rate, understanding of physical function, and important early warning of cardiac work abnormalities, and accurate monitoring of dynamic heart rate on smart wearable devices is not easy because There are many factors to consider in heart rate monitoring, including human skin color, fat and thin, body temperature, static, walking, running and optical structure design. It is necessary to accurately measure different people and different motion states by the same algorithm.

In response to the above problems, SiliconLabs launched a heart rate sensor Si1144, with dynamic heart rate monitoring, ultra-low power consumption, high accuracy, simple optical design, free algorithm library, etc., customers can quickly apply to smart wearable devices, Shiqiang has already represented this product. Figure 1 below is the heart rate sensor Structure diagram with integrated PD, ADC, filter and LED driver.

Figure 1: Heart rate sensor Structure diagram

Program advantage

First, the dynamic heart rate

Sampling the HRM algorithm of EFM32+SI1144+Siliconlabs, through G-sensor with dynamic compensation, high accuracy, comparable to the monitoring effect of POLAR heart rate belt and MIO watch.

Second, ultra low power consumption

Standby power consumption is less than 500nA, dynamic heart rate detection power consumption is 650uA, which is several times lower than competitors' power consumption, which is very suitable for ultra-low power consumption requirements of wearable products.

Third, the structure is simple

The green LED and sensor are packaged together to simplify the optical structure and make it easy to design.

Fourth, free algorithm

Provides Siliconlabs' HRM algorithm library, which can read out heart rate values ​​in a simple configuration, without the need for complex algorithm processing, to quickly complete product design.

Program evaluation

Figure 2 below is SiliconLabs' DemoWatch for evaluating the SI1144 heart rate sensor. Dynamic heart rate monitoring effect.

Figure 2: DemoWatch for SiliconLabs

Figure 3 below is a comparison test, in which blue is the watch of SiliconLabs, red is the Polar heart rate belt, green is the MIO watch, and a test process from slow walking - jogging - running - running - running - jogging, total test 12 minutes, from the test results analysis, comparable to the monitoring effect of the POLAR heart rate belt and MIO watches.

Figure 3: SiliconLabs Heart Rate Sensor Comparative analysis of measurement results

Si1144 heart rate sensor Features:

Package: 4.9x2.85x1.2mm small package

Communication interface: I2C interface to MCU

Internal structure: Built-in 525nm green LED to simplify optical isolation design

?LED driver: can externally drive 3 LEDs, the maximum drive current is 360mA

Power supply: chip operating voltage 1.71-3.6V

SI1144 heart rate sensor Mainly used in smart wearable devices, equipped with SI1144 dynamic heart rate sensor High accuracy and low power consumption can greatly enhance the competitiveness of the product and a better user experience. For more solutions and product information, contact Shiqiang, an authorized distributor of SILICONLABS.