Unable to send and receive images between 2 Raspberry connected to Zigbee via UART.

[jsulm]

@Rika I suggest you implement the receiving part in a proper way: without mixing asynchronous and synchronous ways to read data. Remove the loop from serial::on_readdata(). Put QByteArray ba as member variable in the class. Accumulate data in ba untill you got all data.

[Rika]

@jsulm @mrjj I used qDebug to find out how much data was sent and received. I sent a 30kB image, the data I got from "qDebug()<<ba.size()<<"sizeeeee:";" was 132, I tried many times and all received 132. I used different photos, they gave different results but always the same.

[jsulm]

@Rika Please read https://doc.qt.io/qt-5/qserialport.html#waitForReadyRead "This function blocks until new data is available for reading and the readyRead() signal has been emitted" and my previous post (no need for waitForReadyRead and the loop).

[Rika]

@jsulm You mean this?

void serial::on_readdata()
{
    QByteArray ba(serialPort->readAll());
    qDebug()<<ba.size()<<"sizeeeee:";
    QFile newDoc("/home/pi/Desktop/imagexx.jpg");
            if(newDoc.open(QIODevice::WriteOnly)){
                newDoc.write(ba);
            }
            newDoc.close();
}

[jsulm]

@Rika No, not like this. Please read my post above "Put QByteArray ba as member variable in the class. Accumulate data in ba untill you got all data."

[Rika]

@jsulm Sorry, I don't really understand what you mean. Can you give an example with code?

[jsulm]

@Rika

void serial::on_readdata()
{
    ba.apend(serialPort->readAll());
    qDebug()<<ba.size()<<"sizeeeee:";
    if (ba.size() == imageSize) {
        QFile newDoc("/home/pi/Desktop/imagexx.jpg");
        if(newDoc.open(QIODevice::WriteOnly)){
            newDoc.write(ba);
        }
        newDoc.close();
    }
}

[Rika]

@jsulm I tried it and it failed, I sent 31021 bytes and always received 241 bytes.

[mrjj]

@Rika
So it only shows
qDebug()<<ba.size()<<"sizeeeee:";
1 time with size 241 ?

[Rika]

@mrjj No, the last time was 241. My old way it also received only 241 bytes, so I was thinking of the possibility of an error sent by the program.

[mrjj]

@Rika said in Unable to send and receive images between 2 Raspberry connected to Zigbee via UART.:

No, the last time was 241.

So you do get mutiple
qDebug()<<ba.size()<<"sizeeeee:";
messages ?

[Rika]

@mrjj
144 sizeeeee:
160 sizeeeee:
176 sizeeeee:
192 sizeeeee:
208 sizeeeee:
224 sizeeeee:
240 sizeeeee:
241 sizeeeee:

[jsulm]

@Rika As I already said: you have to accumulate all these data in ba and when you got everything then you store it in the file.
Again the code:

void serial::on_readdata()
{
    ba.apend(serialPort->readAll());
    qDebug()<<ba.size()<<"sizeeeee:";
    if (ba.size() == imageSize) {
        QFile newDoc("/home/pi/Desktop/imagexx.jpg");
        if(newDoc.open(QIODevice::WriteOnly)){
            newDoc.write(ba);
        }
        newDoc.close();
    }
}

[mrjj]

@Rika
But it stops at 241 every time?

Maybe its due to data.
Could you try in your sent function

void serial::on_pushButton_2_clicked()
{


        QByteArray ba;
        ba.fill('A', 1000);
        if(serialPort->isOpen()==true){
            serialPort->write(ba);
            qDebug()<<ba.size()<<"size_send:";
        }
}

and see if that changes how you the reading goes.
This just sends 1000 A.

Also i wonder if write will copy the data and then send / if write sent it all there as else we have the issue of the sent buffer running out of scope.

[Rika]

@jsulm I have made your way, the above is the result from qDebug (). It only received 241 bytes so file imagexxx.jpg was not created. (my imageSize= 31021).

[J.Hilk]

@Rika said in Unable to send and receive images between 2 Raspberry connected to Zigbee via UART.:

@jsulm I have made your way, the above is the result from qDebug (). It only received 241 bytes so file imagexxx.jpg was not created. (my imageSize= 31021).

at this point, you're not getting away with a simple I've tried that, it does not work.

@jsulm is absolutely correct. Show us your actual code

[Rika]

@mrjj I tried with 1000 A, received only 190

[mrjj]

@J-Hilk
Do you know if write blocks ?
QByteArray ba; // local
ba.fill('A', 1000);
if(serialPort->isOpen()==true){
serialPort->write(ba); // blocks here ? as ba is by reference

[Rika]

@J-Hilk

Send:

#include "ui_serial.h"
#include <QDebug>
#include <QBuffer>
#include <QPixmap>
#include <QFile>


serial::serial(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::serial)
{
    ui->setupUi(this);

    serialPort = new QSerialPort(this);
    serialPort->setPortName("ttyAMA0");
    serialPort->setBaudRate(QSerialPort::Baud115200);
    serialPort->setDataBits(QSerialPort::Data8);
    serialPort->setStopBits(QSerialPort::OneStop);
    serialPort->setFlowControl(QSerialPort::NoFlowControl);
    serialPort->open(QIODevice::ReadWrite);

    if (serialPort->isOpen() == true){
        qDebug() <<"Port Opened....";
        connect(serialPort, SIGNAL(readyRead()), this, SLOT(on_readdata()));
    }
}
void serial::on_pushButton_2_clicked()
{
    QFile* imageFile = new QFile("/home/pi/Desktop/image.jpg");
        imageFile->open(QIODevice::ReadOnly);
        QByteArray ba = imageFile->readAll();
        imageFile->close();
        delete imageFile;
        if(serialPort->isOpen()==true){
            serialPort->write(ba);
            qDebug()<<ba.size()<<"size_send:";
        }
}

Rec:

#include "serial.h"
#include "ui_serial.h"
#include <QtSerialPort/QSerialPort>
#include <QDebug>
#include <QBuffer>
#include <QPixmap>
#include <QFile>
#include <QMessageBox>

serial::serial(QWidget *parent) :
   QMainWindow(parent),
   ui(new Ui::serial)
{
   ui->setupUi(this);

   serialPort = new QSerialPort(this);
   serialPort->setPortName("ttyAMA0");
   serialPort->setBaudRate(QSerialPort::Baud115200);
   serialPort->setDataBits(QSerialPort::Data8);
   serialPort->setStopBits(QSerialPort::OneStop);
   serialPort->setFlowControl(QSerialPort::NoFlowControl);
   serialPort->open(QIODevice::ReadWrite);

   if (serialPort->isOpen() == true){
       qDebug() <<"Port Opened....";
       connect(serialPort, SIGNAL(readyRead()), this, SLOT(on_readdata()));
   }

}

serial::~serial()
{
   delete ui;
   serialPort->close();
}


void serial::on_readdata()
{
   ba.append( serialPort->readAll());
   qDebug()<<ba.size()<<"sizeeeee:";
   if (ba.size() == 31021) {
       QFile newDoc("/home/pi/Desktop/imagexx.jpg");
           if(newDoc.open(QIODevice::WriteOnly)){
               newDoc.write(ba);
           }
           newDoc.close();
   }
//    ui->label->setText(ba);

//      QPixmap b;
//      if(b.loadFromData(ba,"JPG")){
//          ui->label->setPixmap(b);
//      }

}

[J.Hilk]

@mrjj IIRC, it's passed on to the OS during the write call and that copies the data. But I'm not entirely sure 😬