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QtMagnetometer Sensor Example Using QtMobility Project

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This code snippet shows how to use Qt Mobilty's QMagnetometer sensor.

Article Metadata
Code ExampleTested with
Devices(s): N8,C7,E7
Compatibility
Platform(s): Symbian
Symbian
Article
Keywords: QMagnetometer, Qt Mobility, Sensor API
Created: chintandave_er (19 Nov 2010)
Last edited: hamishwillee (11 Oct 2012)

Contents

Preconditions

Read this for how to CS001615 - Setting up Qt Mobility

Project File (.pro file)

  • Add the Qt Mobility project configuration option in the .Pro file as shown below
CONFIG += mobility
MOBILITY += sensors
  • here is the full project(.pro) file.
QT       += core gui
 
TARGET = QtMagnetometer
TEMPLATE = app
 
 
SOURCES += main.cpp\
magnetometer.cpp
 
HEADERS += magnetometer.h
 
CONFIG += mobility
CONFIG += debug
MOBILITY = sensors
 
symbian {
TARGET.UID3 = 0xe26021e7
# TARGET.CAPABILITY +=
TARGET.EPOCSTACKSIZE = 0x14000
TARGET.EPOCHEAPSIZE = 0x020000 0x800000
}

Header

Here is the magnetometer.h header file.

#include <QtGui/QMainWindow>
#include <QGraphicsView>
#include <QBasicTimer>
#include <QTimer>
#include <QMagnetometer> // Add Sensor Class
 
// add Qt Mobility Project Namespace
QTM_USE_NAMESPACE
 
class QGraphicsRectItem;
class QGraphicsSimpleTextItem;
 
 
class Magnetometer : public QGraphicsView
{
Q_OBJECT
 
public:
Magnetometer(QWidget *parent = 0);
 
protected:
bool event(QEvent *event);
 
private:
void updateMagnetometerSensor();
 
private:
QGraphicsRectItem *Rect;
QGraphicsSimpleTextItem *text;
QMagnetometer *MagnetometerSensor;
QBasicTimer Timer;
QTimer inactiveTimer;
};


Source

#include "magnetometer.h"
#include <QGraphicsRectItem>
#include <QGraphicsSimpleTextItem>
#include <QResizeEvent>
 
// include timer event
#include <QTimerEvent>
#include <QDebug>
 
Magnetometer::Magnetometer(QWidget *parent) : QGraphicsView(parent), Rect(0), text(0), MagnetometerSensor(0)
{
QGraphicsScene *scene = new QGraphicsScene(this);
setScene(scene);
 
Rect = new QGraphicsRectItem();
 
text = new QGraphicsSimpleTextItem(Rect);
text->setBrush(Qt::gray);
scene->addItem(Rect);
 
MagnetometerSensor = new QMagnetometer(this);
inactiveTimer.setSingleShot(true);
 
if (!Timer.isActive())
Timer.start(20, this);
 
// start the sensor
if (!MagnetometerSensor->isActive())
MagnetometerSensor->start();
 
if (!MagnetometerSensor->isActive())
{
qDebug() << "Magnetometer sensor didn't start!" << endl;
}
 
setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
}
 
bool Magnetometer::event(QEvent *event)
{
switch (event->type()) {
case QEvent::Timer:
if (static_cast<QTimerEvent*>(event)->timerId() == Timer.timerId())
updateMagnetometerSensor(); // update the sensor data
break;
default:
break;
}
return QGraphicsView::event(event);
}
 
void Magnetometer::updateMagnetometerSensor()
{
QMagnetometerReading *reading = MagnetometerSensor->reading();
qreal x = 0.0f;
qreal y = 0.0f;
qreal z = 0.0f;
qreal calibrationLevel = 0.0f;
if (reading) {
x = reading->x();
y = reading->y();
z = reading->z();
calibrationLevel = reading->calibrationLevel();
 
// set the text and display it on the screen
QLocale c(QLocale::C);
text->setText("x: " + c.toString(x) + " y: " + c.toString(y) + " z: " + c.toString(z) + "\n\nMagnetometer Calibration Level: " +
 
c.toString(calibrationLevel));
 
}
}

Postconditions

Here is the QtMagnetometer Application's Screenshot. You can change the Magnetometer Sensor data like X , Y , Z Direction and Calibration Level from Qt Simulator.

QtMagnetometerSimulator.png QtMagnetometer.png

Example Applications

Example application can be found on the following link File:QtMagnetometer.zip.

Related Articles

Turning phone into magnetic compass using Qt mobility project

Accelerometer Sensor Example Using QtMobility Project

Compass Sensor Example Using QtMobility Project


-- chintandave_er 05:40, 9 December 2010 (UTC)

This page was last modified on 11 October 2012, at 04:23.
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