Accelerometer Sensor Example Using QtMobility Project

Overview

This code snippet shows how to use QAccelerometer Sensor using Qt Mobility Project and display sensor data in the screen. This Example use Sensor API of Qt Mobilty.

PreCondition

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));
 
     }
}

PostCondition

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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