用Arduino校准Adafruit LSM303

Question

我有一个阿达夫鲁特LSM303加速度计和指南针连接到一个阿迪诺尤诺。

我使用了Adafruit推荐的校准草图之一(见下面)，并获得了以下输出：

• Accel Minimum：-8.55 -10.16-14.12
• 最高值: 9.89 11.26 15.26
• 迷你：-60.09-57.55 -130.51
• 最大Mag : 69.64 78.09 68.88

如何获得校准输出，并使用Adafruit的推荐代码校准指南针

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_LSM303_U.h>

/* Assign a unique ID to these sensors */
Adafruit_LSM303_Accel_Unified accel = Adafruit_LSM303_Accel_Unified(54321);
Adafruit_LSM303_Mag_Unified mag = Adafruit_LSM303_Mag_Unified(12345);

float AccelMinX, AccelMaxX;
float AccelMinY, AccelMaxY;
float AccelMinZ, AccelMaxZ;

float MagMinX, MagMaxX;
float MagMinY, MagMaxY;
float MagMinZ, MagMaxZ;

long lastDisplayTime;

void setup(void) 
{
  Serial.begin(9600);
  Serial.println("LSM303 Calibration"); Serial.println("");

  /* Initialise the accelerometer */
  if(!accel.begin())
  {
    /* There was a problem detecting the ADXL345 ... check your connections */
    Serial.println("Ooops, no LSM303 detected ... Check your wiring!");
    while(1);
  }
  /* Initialise the magnetometer */
  if(!mag.begin())
  {
    /* There was a problem detecting the LSM303 ... check your connections */
    Serial.println("Ooops, no LSM303 detected ... Check your wiring!");
    while(1);
  }
  lastDisplayTime = millis();
}

void loop(void) 
{
  /* Get a new sensor event */ 
  sensors_event_t accelEvent; 
  sensors_event_t magEvent; 

  accel.getEvent(&accelEvent);
  mag.getEvent(&magEvent);

  if (accelEvent.acceleration.x < AccelMinX) AccelMinX = accelEvent.acceleration.x;
  if (accelEvent.acceleration.x > AccelMaxX) AccelMaxX = accelEvent.acceleration.x;

  if (accelEvent.acceleration.y < AccelMinY) AccelMinY = accelEvent.acceleration.y;
  if (accelEvent.acceleration.y > AccelMaxY) AccelMaxY = accelEvent.acceleration.y;

  if (accelEvent.acceleration.z < AccelMinZ) AccelMinZ = accelEvent.acceleration.z;
  if (accelEvent.acceleration.z > AccelMaxZ) AccelMaxZ = accelEvent.acceleration.z;

  if (magEvent.magnetic.x < MagMinX) MagMinX = magEvent.magnetic.x;
  if (magEvent.magnetic.x > MagMaxX) MagMaxX = magEvent.magnetic.x;

  if (magEvent.magnetic.y < MagMinY) MagMinY = magEvent.magnetic.y;
  if (magEvent.magnetic.y > MagMaxY) MagMaxY = magEvent.magnetic.y;

  if (magEvent.magnetic.z < MagMinZ) MagMinZ = magEvent.magnetic.z;
  if (magEvent.magnetic.z > MagMaxZ) MagMaxZ = magEvent.magnetic.z;

  if ((millis() - lastDisplayTime) > 1000)  // display once/second
  {
    Serial.print("Accel Minimums: "); Serial.print(AccelMinX); Serial.print("  ");Serial.print(AccelMinY); Serial.print("  "); Serial.print(AccelMinZ); Serial.println();
    Serial.print("Accel Maximums: "); Serial.print(AccelMaxX); Serial.print("  ");Serial.print(AccelMaxY); Serial.print("  "); Serial.print(AccelMaxZ); Serial.println();
    Serial.print("Mag Minimums: "); Serial.print(MagMinX); Serial.print("  ");Serial.print(MagMinY); Serial.print("  "); Serial.print(MagMinZ); Serial.println();
    Serial.print("Mag Maximums: "); Serial.print(MagMaxX); Serial.print("  ");Serial.print(MagMaxY); Serial.print("  "); Serial.print(MagMaxZ); Serial.println(); Serial.println();
    lastDisplayTime = millis();
  }
}

Answer 1

在链接到的adafruit页面上，它说“我们可以使用atan2()函数来计算Y和X轴读数所定义的矢量的角度”，我还找到了关于在给定三轴磁强计读数时如何计算罗盘航向的霍尼韦尔的指示，它证实了对于上面的代码，公式应该如下：

float magFieldRad = atan2(magEvent.magnetic.x, magEvent.magnetic.y); // compass in Radians
float magFieldDeg = (magFieldRad * 180) / 3.1415; // compass in Degrees