accelerometerfilter.cpp Example File

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 #include <math.h>
 #include "accelerometerfilter.h"

 #define RADIANS_TO_DEGREES 57.2957795

 AccelerometerFilter::AccelerometerFilter()
     : x(0), y(0), z(0)
 {
 }

 bool AccelerometerFilter::filter(QAccelerometerReading *reading)
 {
     qreal rx = reading->x();
     qreal ry = reading->y();
     qreal rz = reading->z();

     qreal divider = sqrt(rx * rx + ry * ry + rz * rz);

     // Lowpass factor
 #ifdef Q_OS_SYMBIAN
     float lowPassFactor = 0.10;
 #else
     float lowPassFactor = 0.05;
 #endif

     // Calculate the axis angles in degrees and reduce the noise in sensor
     // readings.
     x += (acos(rx / divider) * RADIANS_TO_DEGREES - 90 - x) * lowPassFactor;
     y += (acos(ry / divider) * RADIANS_TO_DEGREES - 90 - y) * lowPassFactor;
     z += (acos(rz / divider) * RADIANS_TO_DEGREES - 90 - z) * lowPassFactor;

     // The orientations of the accelerometers are different between
     // Symbian and Maemo devices so we use the different axes
     // depending on the platform.
 #if defined(Q_OS_SYMBIAN)
     emit rotationChanged(-y);
 #else
     emit rotationChanged(x);
 #endif

     // Don't store the reading in the sensor.
     return false;
 }