hello there,
I'm working on my graduation project which about finds the angles of the IMU sensor.
I'm using sparkfun lsm9ds1 IMU sensor also I'm using sparkfun " LSM9DS1_Setting "code but the result of this code is raw data and I want to convert the gyroscope and accelerometer data into angles.
I tried to use this formula [angle_x= angle_x +(imu.calcGyro(imu.gx)) * Time] and I'm not sure if the result was correct and I have this formula [angle_accel = arctg( Ay / sqrt( Ax^2 + Az^2 ) )] but I didn't use it yet.
so, I'm wondering if it is right to use these formulas and how to write their codes right?
The raw values from a MEMS gyro sensor is the acceleration and de-acceleration of the rotation [see post of MarkT]. It is not the classic gyroscope that you might expect.
For a digital spirit level, you only need the accelerometer and a low-pass filter to measure the earth gravity. That is a "static" value, a spirit level is not a flying drone.
Do you want the dynamic values of yaw, pitch and roll ?
Have a look at this: LSM9DS1/LSM9DS1_MS5611_BasicAHRS_t3.ino at master · kriswiner/LSM9DS1 · GitHub (line 539).
Adafruit has a tutorial: Overview | How to Fuse Motion Sensor Data into AHRS Orientation (Euler/Quaternions) | Adafruit Learning System.
Sensor fusion combines all sensors and eliminates the weakness of each sensor.
Koepel:
The raw values from a MEMS gyro sensor is the acceleration and de-acceleration of the rotation. It is not the classic gyroscope that you might expect.
No, the raw values from a MEMS gyro sensor are rates of turn, which is why its called a "rate gyro". For instance
10 degress/second is a rate of turn.
Koepel:
Do you want the dynamic values of yaw, pitch and roll ?
sorry, but I don't know what these are?
atan2() is the function you need for converting cartesian pairs to an angle. For instance if your
sensor has x, y, z outputs, the angle from vertical would be
atan2(sqrt(xx+yy), z)
√(x^2+y^2) is simply the magnitude of the gravity component in the sensor's xy plane, z is
the gravity component in the sensor's z direction.
atan2() uses the signs of both arguments to determine the correct quadrant for the resultant
angle (which of course is in radians, not degrees, as its a mathematical function). Sometimes
the signs matter, for instance telling you if you are upside down or not(!)
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