Guide to gyro and accelerometer with Arduino including Kalman filtering

Using Arduino Sensors
194

Lauszus:
First of all, how did you calculate your sensitivity?
If you use either 3.3 or 5 volt as reference, it's either:
0.0033/3.31023=1.023
or
0.0033/51023=0.67518
As the sensor has a sensitivity of 3.3 mV/ °/s
Or do you use a different reference? As i can calculate you use 4.711952801 volt as reference (0.0033/4.711952801*1023=0.716454545).

Why do you need this line:

gyroAngle = abs((gyroRotation - 360 * ceil(gyroRotation / 360))); // Round up between 0-360

What you call "gyroRotation", is actually the angle :slight_smile:

For more precision use integration.
Something like this would work:

#define OFFSET 0.0005

gyroRaw = analogRead(0);
gOffset = OFFSET * gyroRaw + (1-OFFSET) * gOffset;
gyroSpeed = (gyroRaw - gOffset)/sensitivity;

gyroAngle += gyroSpeed*dtime/1000;




See this page for more information: http://www.hitechnic.com/blog/gyro-sensor/htway/

Regards
Lauszus

Hey, thanks for the replay.

I'm using 3.3v so i changed the sensitivity to 1.023, now the numbers are even less precise.
the gyroZero after calibration is around 325, and the gyro goes about -+300.

I removed the gyroAngle = abs((gyroRotation - 360 * ceil(gyroRotation / 360))); // Round up between 0-360

When i use this:

#define OFFSET 0.0005

gyroRaw = analogRead(0);
gOffset = OFFSET * gyroRaw + (1-OFFSET) * gOffset;
gyroSpeed = (gyroRaw - gOffset)/sensitivity;

gyroAngle += gyroSpeed*dtime/1000;

The numbers goes crazy and keep going up even when the gyro doesn't move.

Bottom line:
Sensitivity = 1.023 - When i move my object 90 Degrees, the gyro showes 50-55 Degrees.
Sensitivity = 0.716454545 - When i move my object 90 Degrees, the gyro showes 83-88 Degrees.

Those drifts just getting worse every move so after few movements the gyro isn't helpfull.

Any ideas ?