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);
        }
    }
}