Accelerometer Sensor Example Using QtMobility Project

This code snippet shows how to use the Qt Mobilty QAccelerometer and Sensor APIs to get and display sensor data.

Article Metadata

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Code Example

Source file: Media: QtAccelerometer_QtMobility.zip

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Tested with

Devices(s): N8,C7,E7

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Compatibility

Platform(s): Symbian

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Article

Keywords: QAccelerometer,Qt Mobility ,Sensor API

Created: chintandave_er (18 Nov 2010)

Last edited: hamishwillee (11 Oct 2012)

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 = QtAccelerometer
TEMPLATE = app
 
 
SOURCES += main.cpp\
        accelerometer.cpp
 
HEADERS  += accelerometer.h
 
CONFIG += mobility
CONFIG += debug
MOBILITY = sensors
 
symbian {
    TARGET.UID3 = 0xe239264e
    # TARGET.CAPABILITY += 
    TARGET.EPOCSTACKSIZE = 0x14000
    TARGET.EPOCHEAPSIZE = 0x020000 0x800000
}

Header

Here is the accelerometer.h header file.

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

Source

#include "accelerometer.h"
 
#include <QGraphicsRectItem>
#include <QGraphicsSimpleTextItem>
#include <QResizeEvent>
#include <QTimerEvent> // timer event
#include <QDebug> 
 
Accelerometer::Accelerometer(QWidget *parent) : QGraphicsView(parent), Rect(0), text(0), accelerometerSensor(0)
{
    QGraphicsScene *scene = new QGraphicsScene(this);
    setScene(scene);
 
    Rect = new QGraphicsRectItem();
 
    text = new QGraphicsSimpleTextItem(Rect);
    text->setBrush(Qt::gray);
    scene->addItem(Rect);
 
    accelerometerSensor = new QAccelerometer(this);
    inactiveTimer.setSingleShot(true);
 
    if (!Timer.isActive())
        Timer.start(20, this);
 
    // start the sensor
    if (!accelerometerSensor->isActive())
        accelerometerSensor->start();
 
    if (!accelerometerSensor->isActive())
    {
        qDebug() << "accelerometer sensor didn't start!" << endl;
    }
 
    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
}
 
bool Accelerometer::event(QEvent *event)
{
    switch (event->type()) {
    case QEvent::Timer:
        if (static_cast<QTimerEvent*>(event)->timerId() == Timer.timerId())
            updateXYZPosition(); // update the xyz position
        break;
    default:
        break;
    }
    return QGraphicsView::event(event);
}
 
void Accelerometer::updateXYZPosition()
{
    QAccelerometerReading *reading = accelerometerSensor->reading();
    qreal xacceleration = 0.0f;
    qreal yacceleration = 0.0f;
    qreal zacceleration = 0.0f;
    if (reading) {
        xacceleration = reading->x();
        yacceleration = reading->y();
        zacceleration = reading->z();
 
        // for debug purpose
        qDebug()  << "xacceleration x" << endl;
        qDebug()  << xacceleration << endl;
 
        qDebug()  << "yacceleration y" << endl;
        qDebug()  << yacceleration << endl;
 
        qDebug()  << "zacceleration z" << endl;
        qDebug()  << zacceleration << endl;
 
        // set the text and display it on the screen
        QLocale c(QLocale::C); 
        text->setText("x:  " + c.toString(xacceleration) + " y:  " + c.toString(yacceleration) + " z:  " + c.toString(zacceleration));
 
     }
}

Postconditions

Here is the QtAccelerometer Application's Screenshot. You can change the Accelerometer Sensor data from Qt Simulator.

Example Applications

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

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