New High-Speed Optical Heart Rate Sensor Optimised for Measuring Blood Pressure, Stress & Vascular Age

Class-leading detection accuracy and low power consumption support the increasing demand for vital sign sensing

ROHM has recently announced the availability of an optical heart rate sensor for smart bands and watches capable of measuring blood pressure, stress and vascular age at a high-speed 1024Hz sampling rate. The BH1792GLC, which is ROHM’s 2nd generation optical heart rate sensor, features its high accuracy and low power consumption. A current consumption of only 0.44mA (during heart rate measurement), the lowest in the industry*, contributes to longer operating time. And the 1024Hz sampling rate makes it possible to measure heart rate up to 32 times faster than conventional solutions while also supporting vital sign sensing such as vascular age and stress measurement demanded by the latest wearable and fitness devices.

In recent years there has been a growing demand for wearables that can measure not only heart rate, but other vital signs as well such as stress and vascular age to monitor and manage health. However, measuring complicated vital signs requires an increased sampling frequency, which can lead to higher power consumption and decreased battery life.

In response, ROHM leveraged original infrared filtering technology and optical sensor expertise cultivated over many years to develop a low power heart rate sensor that provides high accuracy measurement even under strong IR environments such as direct sunlight or during intense motion activities. And the high-speed sampling rate meets the continuously evolving needs of the IoT and wearable markets.

A heart rate sensor evaluation board (BH1792GLC-EVK-001) for use with ROHM sensor shields that connect to open platform MCU boards (e.g. Arduino Uno) is also available for purchase from online distributors. Moving forward, ROHM will continue to develop solutions that achieve greater safety and convenience in wearable and other portable applications.

Key Features

1. Meets the growing demand for vital sign sensing

The high-speed 1024Hz sampling rate makes it possible to measure more complicated vital signs like blood pressure, stress and vascular age. And an infrared sensor is built in for sensing when the device is worn, simplifying system configuration by integrating this component into the sensor itself.

2. Original optical filter achieves high accuracy detection

An original optical filter structure integrating IR cut and green filters allows only green wavelengths to pass through, reducing susceptibility to external noise such as IR and red light by up to 10x compared with conventional solutions. This enables high accuracy detection even under noisy IR conditions, including direct sunlight and strenuous motion activity.

3. Class-leading low power consumption contributes to longer battery life

When combined with ROHM’s green LED (SMLMN2ECT) optimized for the light receiving characteristics of the heart rate sensor, the improved optical design makes it possible to achieve a class-leading low current consumption of 0.44mA (during heart rate measurement).

In addition, unlike conventional products, a FIFO (First In First Out) buffer is added to reduce power consumption of the Host side controller (e.g. MCU, Applications Processor etc.). This decreases the power consumed by the pulse sensor, contributing to longer application battery life.

4. Optional sensor shield evaluation board facilitates sensor evaluation testing and algorithm development

A heart rate sensor evaluation board (BH1792GLC-EVK-001) for use with our sensor shield (SensorShield-EVK-001) is available for purchase through online distributors. The sensor shield supports open platform MCU boards such as Arduino Uno.

Target Applications

● Wearables such as smart bands and watches
● Smartphones
● Other devices requiring vital sign sensing