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2010-03-01
, 04:47
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Posts: 63 |
Thanked: 52 times |
Joined on Jan 2006
@ Brisbane, Australia
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#2
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http://doc.trolltech.com/4.6/qfile.html
On Unix, there are some special system files (e.g. in /proc) for which size() will always return 0, yet you may still be able to read more data from such a file; the data is generated in direct response to you calling read(). In this case, however, you cannot use atEnd() to determine if there is more data to read (since atEnd() will return true for a file that claims to have size 0). Instead, you should either call readAll(), or call read() or readLine() repeatedly until no more data can be read.
On Unix, there are some special system files (e.g. in /proc) for which size() will always return 0, yet you may still be able to read more data from such a file; the data is generated in direct response to you calling read(). In this case, however, you cannot use atEnd() to determine if there is more data to read (since atEnd() will return true for a file that claims to have size 0). Instead, you should either call readAll(), or call read() or readLine() repeatedly until no more data can be read.
__________________
Programmer, connectivity, sensors, Jolla/llornkcor technologies
Programmer, connectivity, sensors, Jolla/llornkcor technologies
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2010-03-01
, 05:18
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Posts: 13 |
Thanked: 18 times |
Joined on Jun 2009
@ India
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#3
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Try following code, it works for me.
static const QString PROC_ENTRY = "/sys/class/i2c-adapter/i2c-3/3-001d/coord";
QFile f(PROC_ENTRY);
if (!f.exists() or !f.open(QIODevice::ReadOnly | QIODevice::Text)) {
qDebug() << "could not read motion data";
}
else {
QByteArray line = f.readLine();
QRegExp rx("([0-9-]+) ([0-9-]+) ([0-9-]+)");
rx.indexIn(line);
qreal x = rx.cap(1).toInt();
qreal y = rx.cap(2).toInt();
qreal z = rx.cap(3).toInt();
mCurrentPos.setX(x);
mCurrentPos.setY(y);
f.close();
}
static const QString PROC_ENTRY = "/sys/class/i2c-adapter/i2c-3/3-001d/coord";
QFile f(PROC_ENTRY);
if (!f.exists() or !f.open(QIODevice::ReadOnly | QIODevice::Text)) {
qDebug() << "could not read motion data";
}
else {
QByteArray line = f.readLine();
QRegExp rx("([0-9-]+) ([0-9-]+) ([0-9-]+)");
rx.indexIn(line);
qreal x = rx.cap(1).toInt();
qreal y = rx.cap(2).toInt();
qreal z = rx.cap(3).toInt();
mCurrentPos.setX(x);
mCurrentPos.setY(y);
f.close();
}
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2010-03-01
, 12:44
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Posts: 85 |
Thanked: 65 times |
Joined on Jan 2010
@ Ireland
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#4
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Originally Posted by kunal_the_one
That works great! Thanks a million.
Try following code, it works for me.
One more question...using a sample rate of 30 times per second I see some "jitter" on all 3-axes ... +/-18?
Is that right? Caused by gravity? Unusual solar flare activity?
Shep
__________________
- Hey! I also do other stuff Touchscreen apps for Windows and Android
- Currently developing a Diet Assistant/Weight Tracker for the N900
- Hey! I also do other stuff Touchscreen apps for Windows and Android
- Currently developing a Diet Assistant/Weight Tracker for the N900
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2010-07-02
, 12:50
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Posts: 60 |
Thanked: 33 times |
Joined on Apr 2010
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#5
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2010-07-02
, 13:26
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Posts: 85 |
Thanked: 65 times |
Joined on Jan 2010
@ Ireland
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#6
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Originally Posted by raedbenz
Great article, thanks!
http://wiki.forum.nokia.com/index.ph..._N900_using_Qt
__________________
- Hey! I also do other stuff Touchscreen apps for Windows and Android
- Currently developing a Diet Assistant/Weight Tracker for the N900
- Hey! I also do other stuff Touchscreen apps for Windows and Android
- Currently developing a Diet Assistant/Weight Tracker for the N900
I'm trying to parse the accelerometer data using QT.
My code looks like this:
void MainWindow::update_accel() { // read the file /sys/class/i2c-adapter/i2c-3/3-001d/coord QFile file("/sys/class/i2c-adapter/i2c-3/3-001d/coord"); if (!file.open (QIODevice::ReadOnly)) { return; } else { QTextStream stream ( &file ); QString line; while( !stream.atEnd() ) { line = stream.readLine(); ui->label->setText(line); } } }Any clues?
Thanks!
Shep
- Hey! I also do other stuff Touchscreen apps for Windows and Android
- Currently developing a Diet Assistant/Weight Tracker for the N900