An optical heart rate sensor, the BH1792GLC from Rohm Semiconductor, is designed for smart bands and watches. It has high-speed 1024Hz sampling, which makes it possible to measure the heart rate up to 32 times faster than conventional solutions, claims Rohm. It can also be used for measuring blood pressure, stress and vascular age.

The BH1792GLC is the second pulse wave sensor to be developed by Rohm. It has high detection accuracy and when combined with Rohm’s green LED (SMLMN2ECT), which has been optimised for the light receiving characteristics of the heart rate sensor, the optical design makes it possible to achieve low current consumption of 0.44 mA (during pulse measurement).

The BH1792GLC measures 2.8 x 2.8 x 0.9mm. In addition to measuring the heart rate, an infra red sensor makes it possible to detect when the device is being worn. An integrated first in first out (FIFO) memory helps to reduce the power consumption on the host MCU, which in turn decreases the power consumed by the sensor and increases the application drive time.

An optimised optical filter structure with integral infra red (IR) -cut and green filters, which only allow light with green wavelengths to pass through, reduces the susceptibility to external noise such as IR and red light by up to 10x compared with conventional solutions. This facilitates high accuracy detection even under noisy IR conditions.

The heart rate sensor works with supply voltages from 2.5 to 3.6V. Its operating temperature range is between -20 and +85°C.

The BH1792GLC can be used for smart bands, watches, smartphones and other portable devices requiring vital sign sensing.

Samples and OEM quantities of the BH1792GLC are available now.

An evaluation board (BH1792GLC-EVK-001) from Rohm is for use with the heart rate sensor. It is available from the online distributors Chip One Stop, Zyco Store (Core Staff) and RS Components, which can be connected via the Rohm sensor shield with open platform MCU boards such as Arduino Uno.

Visit Rohm at Embedded World: Hall 3A – Stand 332

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