Qserialport does not send a char to arduino

[endure]

I'm having a trouble in trying to send a char (i.e. "R") from my qt5 application on WIN7 to comport which is connected to an Arduino. I intend to blink a led on Arduino and my arduino part works OK.

Here is my qt code:

@#include <QTextStream>
#include <QCoreApplication>
#include <QtSerialPort/QSerialPortInfo>
#include <QSerialPort>
#include <iostream>
#include <QtCore>

QT_USE_NAMESPACE

using namespace std;
QSerialPort serial;

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QTextStream out(stdout);
QList<QSerialPortInfo> serialPortInfoList = QSerialPortInfo::availablePorts();

out << QObject::tr("Total number of ports available: ") << serialPortInfoList.count() << endl;


foreach (const QSerialPortInfo &serialPortInfo, serialPortInfoList) {
    out << endl
        << QObject::tr("Port: ") << serialPortInfo.portName() << endl
        << QObject::tr("Location: ") << serialPortInfo.systemLocation() << endl
        << QObject::tr("Description: ") << serialPortInfo.description() << endl
        << QObject::tr("Manufacturer: ") << serialPortInfo.manufacturer() << endl
        << QObject::tr("Vendor Identifier: ") << (serialPortInfo.hasVendorIdentifier() ? QByteArray::number(serialPortInfo.vendorIdentifier(), 16) : QByteArray()) << endl
        << QObject::tr("Product Identifier: ") << (serialPortInfo.hasProductIdentifier() ? QByteArray::number(serialPortInfo.productIdentifier(), 16) : QByteArray()) << endl
        << QObject::tr("Busy: ") << (serialPortInfo.isBusy() ? QObject::tr("Yes") : QObject::tr("No")) << endl;
}

serial.setPortName("COM5");
serial.open(QIODevice::ReadWrite);
serial.setBaudRate(QSerialPort::Baud9600);
serial.setDataBits(QSerialPort::Data8);
serial.setParity(QSerialPort::NoParity);
serial.setStopBits(QSerialPort::OneStop);
serial.setFlowControl(QSerialPort::NoFlowControl);




    if(!serial.isOpen())
    {
      std::cout<<"port is not open"<<endl;
      //serial.open(QIODevice::ReadWrite);
    }

if(serial.isWritable()==true)
{
    std::cout<<"port writable..."<<endl;
}



QByteArray data("R");

serial.write(data);
serial.flush();
std::cout<<"value sent!!! "<<std::endl;
serial.close();

return 0;

}@

My source code consists of two parts,

1- serialportinfolist .... which works just fine 2- opening and writing data... I get no issue when running the code and the display shows the result as if nothing has gone wrong!

HOWEVER, the led on the board does not turn on when I run this code.

I test this with Arduino Serial Monitor and it turns on but cant turn on from Qt.

[gorbatschow]

Are you sure that the data is not transmitted? Maybe you have incompatible signals. Than look at something like this (http://en.wikipedia.org/wiki/MAX232)