IMU

Introduction

MoonBot Kit Controller Module integrates three functions of triaxial magnetometer, triaxial acceleration and temperature sensor into IMU module. In the Arduino library, we also provide ref:IMU < api-ref-imu > library to facilitate users to access the master control of the current attitude, direction, temperature and other states.

By calling `IMU’, we can quickly obtain the current compass angle, pitch angle, roll angle, gravity acceleration, temperature and other state values.

Read master control current direction

By reading the angle of the compass, we can know the direction of the current master control:

#include <MoonBot.h>

void setup()
{
  IMU.enable();         // IMU Enable
  IMU.calibrateMag();   // IMU magnetometer calibration,the master control needs to flip in the shape of ”∞“
}

void loop()
{
  Serial.print("compass:");
  // Obtain the compass angle(0~360°).When pointing north, the value is 0 or 360
  Serial.println(IMU.getMagAngle());
}

Note

When the main control is flat, the return value is Y axis (see the master control front silk mark) and the northward clip.

When the main control is erected, the return value is the angle between Z axis and North direction.

Obtain Pitch angle or Rolling angle

// Obtain Pitch angle（±180°），When the main control is up, the angle is positive and the downward angle is negative.
int pitch = IMU.getAccAngle(kAccPitch);
// Obtain Rolling angle（±180°），The main control right deviation is positive and the left deviation is negative.
int roll = IMU.getAccAngle(kAccRoll);

Note

MoonBot Kit The main control direction is Y axis (see the main control front silk mark)，Angles are calculated on this premise.。

Acquisition of current acceleration

// Acquisition of acceleration，unit：g，The value at rest is 1.0.
float acceleration = IMU.getAcceleration();

Obtain the current motion state

void loop()
{
    if (IMU.on(kIMUShake)) {
        // If the current master is shaking
        // bright red LED
        LED.setPixelColor(0, 0xff0000);
        LED.setPixelColor(1, 0xff0000);
        LED.show();
    } else if (IMU.on(kIMUFreeFall)) {
        // If the current master is in free fall
        // bright green LED
        LED.setPixelColor(0, 0x00ff00);
        LED.setPixelColor(1, 0x00ff00);
        LED.show();
    } else {
        // If the main control is stationary
        // close LED
        LED.setPixelColor(0, 0x000000);
        LED.setPixelColor(1, 0x000000);
        LED.show();
    }
}

API Reference - IMU

enumeration

enum lsm303_axes_t

  • IMU Directional axis type

value:

kDirX

kDirY

kDirZ

enum lsm303_acc_angle_t

  • IMU Attitude Angle Type。

value:

kAccRoll

kAccPitch

enum imu_state_t

  • IMU Special state type.

value:

kIMUShake

  • IMU Is it in a sloshing state

kIMUFreeFall

  • IMU Is it in a free falling state

Class

class LSM303AGR_IMU_Sensor

  • IMU Drive.

group function
int enable(void);

  • enable IMU

Return

  • 0 enable success, unable failure

int advGetMagAngle(lsm303_axes_t main_axes, lsm303_axes_t sub_axes);

  • Get the plane where the specified spindle and vice-spindle are located, and the angle between the spindle and the North side.

parameters

  • main_axes ：Spindle

  • sub_axes ：Countershaft

Return

  • Angle between the spindle and the North

int getMagAngle(void);
  • Obtain the compass angle，When the main control is placed horizontally, the angle between the positive direction of Y axis and the north is returned;

    when the main control is placed vertically, the angle between the positive direction of Z axis and the north is returned.

Return

  • Angle between the spindle and the North

int getAccAngle(lsm303_acc_angle_t angle_type);

  • Obtain the main control angle.

parameters

  • angle_type ：angle type

Return

  • angle

float getAcceleration(void);

  • Acquisition of acceleration value。

Return

  • Acceleration value，unit：g

bool on(imu_state_t imu_state);

  • Get whether the master control is in some state。

parameters

  • imu_state ：IMU state

Return

  • true IMU In this state,Otherwise, it is not in this state.

bool calibrateMag(void);

  • Calibration of Magnetometer

Return

  • Whether the calibration is completed or not

int16_t temperature(void);

  • Obtain the original temperature value

Return

  • Primitive value of temperature

float temperatureC(void);

  • Get the current temperature，unit：Celsius degree

Return

  • Current temperature，unit：Celsius degree

float temperatureF(void);

  • Current temperature，unit：Fahrenheit degree

Return

  • Current temperature，unit：Fahrenheit degree

group variable
LSM303AGR_ACC_Sensor Acc;

  • Acceleration drive

LSM303AGR_MAG_Sensor Mag;

  • Magnetometer drive