Arduino® Nano 33 BLE Sense Rev2
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Arduino® Nano 33 BLE Sense Rev2
Modified: 12/01/2023
2.4 LPS22HB (U9) Barometer and Temperature Sensor
The LPS22HB pressure sensor IC (U9) includes both a piezoresistive absolute pressure sensor together with a
temperature sensor integrated into a small chip. The pressure sensor (U9) interfaces with the main microcontroller
(U1) via an I2C interface. The sensing element is composed of a micromachined suspended membrane for
measuring absolute pressure, and includes a Wheatstone bridge internally for measuring the the piezoresistive
elements. The temperature perturbations are compensated via an included temperature sensor on-chip. The
absolute pressure can range from 260 to 1260 hPa. Pressure data can be polled via I2C at up to 24-bits, while
temperature data can be polled at up to 16-bits. The Arduino_LPS22HB library provides a ready to use
implementation of the I2C protocol with this chip.
2.5 HS3003 (U8) Relative Humidity and Temperature Sensor
The HS3003 (U8) is a MEMS sensors, designed to provide accurate readings of relative humidity and temperature in
a small package. Temperature-compensation and calibration is performed on-chip, without requiring external
circuitry. The HS3003 can measure the relative humidity from 0% to 100%RH with fast response times (under 4
seconds). The included on-chip temperature sensor (used for compensation) is has a temperature accuracy of
±0.1°C. U8 communicates via the main microcontroller via an I2C bus.
2.5.1 Gesture Detection
Gesture detection utilizes four directional photodiodes to sense reflected IR energy (sourced by the integrated LED)
to convert physical motion information (i.e. velocity, direction and distance) to a digital information. The
architecture of the gesture engine features automatic activation (based on Proximity engine results), ambient light
subtraction, cross-talk cancellation, dual 8-bit data converters, power saving inter-conversion delay, 32-dataset
FIFO, and interrupt driven I2C communication. The gesture engine accommodates a wide range of mobile device
gesturing requirements: simple UP-DOWN-RIGHT-LEFT gestures or more complex gestures can be accurately
sensed. Power consumption and noise are minimized with adjustable IR LED timing.
2.5.2 Proximity Detection
The Proximity detection feature provides distance measurement (E.g. mobile device screen to user’s ear) by
photodiode detection of reflected IR energy (sourced by the integrated LED). Detect/release events are interrupt
driven, and occur whenever proximity result crosses upper and/ or lower threshold settings. The proximity engine
features offset adjustment registers to compensate for system offset caused by unwanted IR energy reflections
appearing at the sensor. The IR LED intensity is factory trimmed to eliminate the need for end-equipment
calibration due to component variations. Proximity results are further improved by automatic ambient light
subtraction.
