Code Examples Sensors API

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Overview

This page points to and provides quick overviews of existing code examples using the "Sensors API":http://doc.qt.nokia.com/qtmobility-1.1.0/sensors-api.html, one of the suite of Qt Mobilty APIs.

Fall detector

The "Fall Detector example":http://wiki.forum.nokia.com/index.php/Qt_Mobility_example_application:_Fall_Detector from Forum Nokia uses the accelerometer in a mobile device to detect if the user has fallen, then uses the

• "Location API":http://doc.qt.nokia.com/qtmobility-1.1.0/location-overview.html to get the user's location

• the "Contacts API":http://doc.qt.nokia.com/qtmobility-1.1.0/contacts.html to store and access an email address to be notified in the event of a fall

• and the "Messaging API ":http://doc.qt.nokia.com/qtmobility-1.1.0/messaging.html to send an email notification with photo attachment.

Fall Dector Screen Shot Here's the code snippet for the fall detector using the Sensors API:

#include <QAccelerometer>

// Neccessary for Qt Mobility API usage
QTM_USE_NAMESPACE

class AccelerationInfo : public QObject, public QAccelerometerFilter
{
 Q_OBJECT

public:

AccelerationInfo(QObject* parent = 0) : QObject(parent)
 {
 m_sensor = new QAccelerometer(this);
 m_sensor->addFilter(this);
 m_sensor->start();
 }

private slots:

// Override of QAcclerometerFilter::filter(QAccelerometerReading*)
 void filter(QAccelerometerReading* reading)
 {
 qreal x = reading->x();
 qreal y = reading->y();
 qreal z = reading->z();

// Process acceleration sensor readings …

qDebug("Current device acceleration: x=%f y=%f z=%f", x, y, z);
 }

private:

QAccelerometer* m_sensor;
};

Use accelerometer to control an Open GL-ES 3D model

This sensors tutorial from "Mobile Qt-Entwicklung":http://www.mobileqt.de/wiki/daten_des_accelerometer_sensors_mit_einem_opengl_objekt_verknuepfen (Mobile Qt Development) shows the accelerometer in an N900 manipulating a 3D model created using Open GL. The "descriptive text is in German":http://www.mobileqt.de/wiki/daten_des_accelerometer_sensors_mit_einem_opengl_objekt_verknuepfen, but all "the code is available in a downloadable package":http://www.mobileqt.de/tutorials/6/glsensordemo-0.1.zip and this "demo video":http://www.youtube.com/watch?v=uJpw0yeHJl8 shows you how it works.

Here is the relevant accelerometer code:

GLWidget::GLWidget(QWidget *parent) :

QGLWidget(parent)

{

setWindowTitle(tr("Sensor-GL-Demo"));
makeCurrent();

setAttribute(Qt::WA_PaintOnScreen);

setAttribute(Qt::WA_NoSystemBackground);
setAutoBufferSwap(false);

xRot = 0;

yRot = 0;
zRot = 0;

_rotationSensorAvailable = false;

_rotationSensor = new QtMobility::QAccelerometer(this);
_rotationSensor->connect();
if (!_rotationSensor->isAvailable()) {
qWarning("No acceleration sensor available!");
} else {
_rotationSensorAvailable = true;
_rotationSensor->setSignalEnabled(false); // we get the values from the sensor itself
_rotationSensor->setUpdateInterval(100); // as quickly as possible
_rotationSensor->start();
}

QTimer *timer = new QTimer(this);

timer->setInterval(10);
QObject::connect(timer, SIGNAL (timeout()), this, SLOT (updateGL()));
timer->start();
showFullScreen();

}