MPU9250_asukiaaa

A library to read values from MPU9250.

Installation

You can install to Arduino IDE with using library manager.

1. Select [Sketch -> Include Library -> Manage Libraries] to open library manager.
2. Search MPU9250 in library manager.
3. Select and install this project.

Connection

For uno, nano and so on.

Arduino	MPU9250
3.3	VCC
A4(SDA)	SDA
A5(SCL)	SCL
GND	GND

For other boards, please check i2c pin assign.

Usage

You can see all function on example project.

Accelerometer

#include <MPU9250_asukiaaa.h>
MPU9250_asukiaaa mySensor;
float aX, aY, aZ, aSqrt;

void setup() {
  Wire.begin();
  mySensor.setWire(&Wire);
  mySensor.beginAccel();
}

void loop() {
  mySensor.accelUpdate();
  aX = mySensor.accelX();
  aY = mySensor.accelY();
  aZ = mySensor.accelZ();
  aSqrt = mySensor.accelSqrt();
  // Do what you want
}

Gyrometer

#include <MPU9250_asukiaaa.h>
MPU9250_asukiaaa mySensor;
float gX, gY, gZ;

void setup() {
  Wire.begin();
  mySensor.setWire(&Wire);
  mySensor.beginGyro();
}

void loop() {
  mySensor.gyroUpdate();
  gX = mySensor.gyroX();
  gY = mySensor.gyroY();
  gZ = mySensor.gyroZ();
  // Do what you want
}

Magnetometer

#include <MPU9250_asukiaaa.h>
MPU9250_asukiaaa mySensor;
float mDirection;
uint16_t mX, mY, mZ;

void setup() {
  Wire.begin();
  mySensor.setWire(&Wire);
  mySensor.beginMag();
}

void loop() {
  Serial.begin(115200);
  mySensor.magUpdate();
  mX = mySensor.magX();
  mY = mySensor.magY();
  mZ = mySensor.magZ();
  mDirection = mySensor.magHorizDirection();
  // Do what you want
}

If you cannot get values by calling magUpdate, try calling beginMag and magUpdate again.

void loop() {
  auto result = mySensor.magUpdate();
  if (result != 0) {
    mySensor.beginMag();
    result = mySensor.magUpdate();
  }
}

If you get values of sensor like this..

Name	Max	Min
magX	70	-30
maxY	110	10

You can calcurate offset values like this.

maxXOffset = - (magXMax + magXMin) / 2
           = - (70 - 30) / 2
           = - 40 / 2
           = -20

magYOffset = - (magYMax + magYMin) / 2
           = - (110 + 10) / 2
           = - 120 / 2
           = -60

Then set the offset values like this.

void setup() {
  mySensor.magXOffset = -20;
  mySensor.magYOffset = -60;
}

Then you can get like this.

Name	Max	Min
magX	50	-50
maxY	50	-50

After setting offset value, you can get magHorizDirection as you expected.

Warning: Offset value changes by temperature or some reason. If you want to get high accuracy value, you should recheck the offset value.

Example about auto calibration (calculating offset values) is here.

With customizable Wire

For ESP32 and so on.

#define SDA_PIN 21
#define SCL_PIN 22

void setup() {
  Wire.begin(SDA_PIN, SCL_PIN);
  mySensor.setWire(&Wire);
}

License

MIT

References

• ArduinoでMPU9250（加速度センサ、磁気センサ）を使う方法
• MPU-9250 | TDK
• MPU-9250Product SpecificationRevision 1.1
• MPU-9250Register Map and DescriptionsRevision 1.6
• HaLakeKit-Library
• Aliexpress MPU9250
• AK8963 datasheet
• jrowberg/i2cdevlib/Arduino/AK8963
• SparkFun_MPU-9250
• 「MPU-9250 ９軸センサモジュール (メーカー品番：MPU-9250)」を使う
• 【PSoC】MPU-9250のデータを取得（加速度、ジャイロ編）