Pressure

Pressure

HAL Example

Device Compatibility

Overview

The pressure sensor reports values for:

  • Pressure
  • Altitude
  • Temperature

Code Example

Below is an example of how to interface with the pressure sensor in MATRIX HAL.

Pressure sensor function references can be found here.

The following section shows how to receive data from the pressure sensor. You can download this example here.

The command below will compile the example. Be sure to pass in your C++ file and desired output file.

g++ -o YOUR_OUTPUT_FILE YOUR_CPP_FILE -std=c++11 -lmatrix_creator_hal
Include Statements

To begin working with the pressure sensor you need to include these header files.

// System calls
#include <unistd.h>
// Input/output streams and functions
#include <iostream>

// Interfaces with pressure sensor
#include "matrix_hal/pressure_sensor.h"
// Holds data from pressure sensor
#include "matrix_hal/pressure_data.h"
// Communicates with MATRIX device
#include "matrix_hal/matrixio_bus.h"
Initial Setup

You'll then need to setup MatrixIOBus in order to communicate with the hardware on your MATRIX device.

int main() {
// Create MatrixIOBus object for hardware communication
matrix_hal::MatrixIOBus bus;
// Initialize bus and exit program if error occurs
if (!bus.Init()) return false;
Main Setup

Now we will create our PressureData and PressureSensor object and use it to receive data from the pressure sensor.

// The following code is part of main()

// Create PressureData object
matrix_hal::PressureData pressure_data;
// Create PressureSensor object
matrix_hal::PressureSensor pressure_sensor;
// Set pressure_sensor to use MatrixIOBus bus
pressure_sensor.Setup(&bus);

// Endless loop
while (true) {
    // Overwrites pressure_data with new data from pressure sensor
    pressure_sensor.Read(&pressure_data);
    // Altitude output is represented in meters
    float altitude = pressure_data.altitude;
    // Pressure output is represented in Pa
    float pressure = pressure_data.pressure;
    // Temperature output is represented in Celsius
    float temperature = pressure_data.temperature;
    // Clear console
    std::system("clear");
    // Output sensor data to console
    std::cout << " [ Pressure Sensor Output ]" << std::endl;
    std::cout << " [ Altitude (m) : " << altitude
            << " ] [ Pressure (Pa) : " << pressure
            << " ] [ Temperature (Celsius) : " << temperature << " ]" << std::endl;

    // Sleep for 20000 microseconds
    usleep(20000);
}

return 0;
}

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