Miniature barometric pressure sensor fits into wearables

In many cases, barometric pressure sensors have not been able to protect against liquids making it difficult to integrate into waterproof products like wearable fitness trackers. Bosch Sensortec’s answer to the challenge is the new BMP384 barometric pressure sensor. This highly accurate sensor uses a special gel that protects it from water ingress as well as other liquids and dust, making it suited for wearables, home appliances, and industrial applications in harsh environments.

Click for larger image. (Image: Bosch Sensortec)

The BMP384 barometric pressure sensor also offers high performance. It provides a relative accuracy of +/- 9 Pa, an absolute accuracy of +/- 50 Pa, and a temperature coefficient offset (TCO) of +/- 1.0 Pa/K. In addition, it offers a low power consumption of 3.4 µA at 1 Hz data rate (typical), ensuring longer battery life in portable devices. The operating temperature range is -40°C to 85°C.

The sensor is available in three power modes: sleep, forced, and normal. In sleep mode no measurements are performed and power consumption is at a minimum ( 2 µA), while in forced mode only a single measurement is performed according to selected measurement and filter options, returning to sleep mode after the measurement is completed. In normal mode the sensor continuously cycles between an active measurement period and an inactive standby period.

BMP384 block diagram (Image: Bosch Sensortec)

This sensor is particularly suited for wearable applications like smartwatches and fitness trackers in activities like swimming and running thanks to the special gel inside the package that protects against liquids such as salt water, rain, sweat and sunscreen, according to Bosch Sensortec. In addition, it comes in a small package size (2.0 × 2.0 × 1 mm3), so it fits into very compact devices.

The sensor also can be designed into home appliances for applications such as water-level detection in washing machines for ensuring accurate water volume measurement and flooding prevention as well as dusty environments such as clog detection in vacuum cleaners.

The BMP384, housed in a metal-lid LGA package, is available now. Bosch Sensortec will showcase the new sensor at the Embedded World conference. The company offers a range of low power sensing devices for portable and wearable devices including the BMI260 family of inertial measurement units (IMUs).