IMU

Inertial Measurement Unit (IMU)

HAL Example

Device Compatibility

Overview

The IMU sensor reports values for:

  • Yaw, Pitch, and Roll
  • Acceleration for x, y, z axes
  • Gyroscope for x, y, z axes
  • Magnetometer for x, y, z axes

Code Example

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

IMU sensor function references can be found here.

The following section shows how to receive data from the IMU 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 IMU sensor you need to include these header files.

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

// Interfaces with IMU sensor
#include "matrix_hal/imu_sensor.h"
// Holds data from IMU sensor
#include "matrix_hal/imu_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 IMUData and IMUSensor object and use it to receive data from the IMU sensor.

    // The following code is part of main()

    // Create IMUData object
    matrix_hal::IMUData imu_data;
    // Create IMUSensor object
    matrix_hal::IMUSensor imu_sensor;
    // Set imu_sensor to use MatrixIOBus bus
    imu_sensor.Setup(&bus);

    // Endless loop
    while (true) {
    // Overwrites imu_data with new data from IMU sensor
    imu_sensor.Read(&imu_data);
    // Accelerometer Output
    float accel_X = imu_data.accel_x;
    float accel_Y = imu_data.accel_y;
    float accel_Z = imu_data.accel_z;
    // Gyroscope Output
    float gyro_X = imu_data.gyro_x;
    float gyro_Y = imu_data.gyro_y;
    float gyro_Z = imu_data.gyro_z;
    // Yaw, Pitch, Roll Output
    float yaw = imu_data.yaw;
    float pitch = imu_data.pitch;
    float roll = imu_data.roll;
    // Magnetometer Output
    float mag_X = imu_data.mag_x;
    float mag_Y = imu_data.mag_y;
    float mag_Z = imu_data.mag_z;  // Z-axis points upward
    // Clear console
    std::system("clear");
    // Output sensor data to console
    std::cout << " [ IMU Sensor Output ]" << std::endl;
    std::cout << " [ Acceleration In X : " << accel_X
                << " ] [ Acceleration In Y : " << accel_Y
                << " ] [ Acceleration In Z : " << accel_Z << " ]" << std::endl;
    std::cout << " [ Gyroscope In X : " << gyro_X
                << " ] [ Gyroscope In Y : " << gyro_X
                << " ] [ Gyroscope In Z : " << gyro_Z << " ]" << std::endl;
    std::cout << " [ Yaw : " << yaw << " ] [ Pitch : " << pitch
                << " ] [ Roll : " << roll << " ]" << std::endl;
    std::cout << " [ Magnetometer in X : " << mag_X
                << " ] [ Magnetometer in Y : " << mag_Y
                << " ] [ Magnetometer in Z : " << mag_Z << " ]" << std::endl;

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

    return 0;
}

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