Barometric pressure and temperature sensor interrupt example

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Overview

This sample application uses a pressure sensor interrupt line to:

  • Inform when a measure is available in the sensor FIFO. Temperature and pressure data are read and displayed in terminal. If floats are supported, estimated altitude is also displayed.

  • Inform when the pressure value crosses a specified threshold. Threshold corresponds to around a 50cm altitude increase. A message is displayed in the terminal.

  • Inform when the pressure value changed more than the specified value between two consecutive samples. Change value corresponds to a finger pressing the sensor. A message is displayed in the terminal.

Wiring

This sample uses an external breakout for the sensor. A devicetree overlay must be provided to identify the I2C/SPI bus and GPIO used to control the sensor.

Building and Running

This sample supports pressure sensor devices. Device needs to be aliased as pressure-sensor. For example:

/ {
        aliases {
                pressure-sensor = &icp201xx;
        };
};

Make sure the aliases are in devicetree, then build and run with:

# From the root of the zephyr repository
west build -b nrf52dk/nrf52832 samples/sensor/pressure_interrupt
west flash

Sample Output

## Default configuration

[00:00:00.266,479] <inf> PRESS_INT_SAMPLE: Starting ICP201xx sample. [00:00:00.273,803] <inf> PRESS_INT_SAMPLE: temp 25.49 Cel, pressure 96.271438 kPa, altitude 447.208465 m [00:00:00.280,914] <inf> PRESS_INT_SAMPLE: temp 25.50 Cel, pressure 96.271331 kPa, altitude 447.234161 m [00:00:00.288,024] <inf> PRESS_INT_SAMPLE: temp 25.49 Cel, pressure 96.266685 kPa, altitude 447.636077 m [00:00:00.295,135] <inf> PRESS_INT_SAMPLE: temp 25.50 Cel, pressure 96.267951 kPa, altitude 447.537078 m [00:00:00.302,246] <inf> PRESS_INT_SAMPLE: temp 25.51 Cel, pressure 96.268577 kPa, altitude 447.488281 m [00:00:00.309,356] <inf> PRESS_INT_SAMPLE: temp 25.50 Cel, pressure 96.269340 kPa, altitude 447.414978 m [00:00:00.316,467] <inf> PRESS_INT_SAMPLE: temp 25.50 Cel, pressure 96.268562 kPa, altitude 447.473663 m [00:00:00.323,547] <inf> PRESS_INT_SAMPLE: temp 25.50 Cel, pressure 96.267341 kPa, altitude 447.596496 m <repeats endlessly>

<when sensor is pressed> [00:00:09.819,061] <inf> PRESS_INT_SAMPLE: PRESSURE CHANGE INTERRUPT

<when the sensor pressure crosses defined threhold> [00:00:09.859,039] <inf> PRESS_INT_SAMPLE: PRESSURE THRESHOLD INTERRUPT

See also

Sensor Interface