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)