Hello,
I am using a 9 DOF IMU returning acceleration, magnetic and angular rates values. I am confidend about the connections (possible to see them in the attached picture). In order to get the aforementioned values, I use the script pitchrollheading from the Arduino 9DOF library (linked to Adafruit libraries). You can see the code I use bellow.
The problem is that it is specified that the provided heading varies from 0 to 360°. However, when I am measuring the values by rotating my IMU, my values do not vary from 0 to 360° at all. After rotating the IMU about 360°, the measurements indicate only a small variation of approximately 100° in between 210° to 290°.
I do not really understand why, I've read that it might be due to the disturbance of the electronic systems around. However, when I use my magnetic compass (that differs from my IMU), I have good measurements indeed in between 0 to 360° in the same room than the one where I also use the IMU.
Thanks for any help !
The used code:
#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_LSM303_U.h>
#include <Adafruit_L3GD20_U.h>
#include <Adafruit_9DOF.h>
/* Assign a unique ID to the sensors */
Adafruit_9DOF dof = Adafruit_9DOF();
Adafruit_LSM303_Accel_Unified accel = Adafruit_LSM303_Accel_Unified(30301);
Adafruit_LSM303_Mag_Unified mag = Adafruit_LSM303_Mag_Unified(30302);
/* Update this with the correct SLP for accurate altitude measurements */
float seaLevelPressure = SENSORS_PRESSURE_SEALEVELHPA;
//
/*!
@brief Initialises all the sensors used by this example
*/
//
void initSensors()
{
if(!accel.begin())
{
/* There was a problem detecting the LSM303 ... check your connections /
Serial.println(F("Ooops, no LSM303 detected ... Check your wiring!"));
while(1);
}
if(!mag.begin())
{
/ There was a problem detecting the LSM303 ... check your connections */
Serial.println("Ooops, no LSM303 detected ... Check your wiring!");
while(1);
}
}
/**************************************************************************/
/*!
*/
/**************************************************************************/
void setup(void)
{
Serial.begin(115200);
Serial.println(F("Adafruit 9 DOF Pitch/Roll/Heading Example")); Serial.println("");
/* Initialise the sensors */
initSensors();
}
//
/*!
@brief Constantly check the roll/pitch/heading/altitude/temperature
*/
//
void loop(void)
{
sensors_event_t accel_event;
sensors_event_t mag_event;
sensors_vec_t orientation;
/* Calculate pitch and roll from the raw accelerometer data /
accel.getEvent(&accel_event);
if (dof.accelGetOrientation(&accel_event, &orientation))
{
/ 'orientation' should have valid .roll and .pitch fields */
Serial.print(F("Roll: "));
Serial.print(orientation.roll);
Serial.print(F("; "));
Serial.print(F("Pitch: "));
Serial.print(orientation.pitch);
Serial.print(F("; "));
}
/* Calculate the heading using the magnetometer /
mag.getEvent(&mag_event);
if (dof.magGetOrientation(SENSOR_AXIS_Z, &mag_event, &orientation))
{
/ 'orientation' should have valid .heading data now */
Serial.print(F("Heading: "));
Serial.print(orientation.heading);
Serial.print(F("; "));
}
Serial.println(F(""));
delay(1000);
}
