[PLEASE HELP] how to make a barcode receiver?
-
@JKSH is it must came from serial port not usb?
@davidlabib said in [PLEASE HELP] how to make a barcode receiver?:
is it must came from serial port not usb?
Qt Serial Port works with serial ports. A USB port is not a serial port.
If your computer doesn't have a serial port, you can use a USB-to-serial converter.
Qt Doc Search for browsers: forum.qt.io/topic/35616/web-browser-extension-for-improved-doc-searches
-
@davidlabib said in [PLEASE HELP] how to make a barcode receiver?:
is it must came from serial port not usb?
Qt Serial Port works with serial ports. A USB port is not a serial port.
If your computer doesn't have a serial port, you can use a USB-to-serial converter.
-
@davidlabib said in [PLEASE HELP] how to make a barcode receiver?:
is it must came from serial port not usb?
Qt Serial Port works with serial ports. A USB port is not a serial port.
If your computer doesn't have a serial port, you can use a USB-to-serial converter.
@JKSH said in [PLEASE HELP] how to make a barcode receiver?:
Qt Serial Port works with serial ports. A USB port is not a serial port.
thats not true. Of course QtSerialPort works with USB.
USB = Universal Serial BusThe code above i've posted definitively works with a USB Barcode scanner and i used it myself already.
-
@davidlabib
use the very first code (RS232).
Then check the COM port of the scanner it is connected to (e.g. on Windows in the Device Manager).in your .pro file add
QT += serialportQSerialPort example usage:
QSerialPort* port = new QSerialPort( this ); port->setBaudRate( QSerialPort::Baud115200 ); // possible something else, also check the manual port->setPort( QPortInfo("COM4") ); // COM port - check Device Manager for connected port if( port->open(QSerialPort::ReadOnly) ) { connect(port, &QSerialPort::readyRead, this, [port]() { if( !port->bytesAvailable() ) return; const QByteArray scannedData = port->readAll(); // ... }); } else { // check port->error() }@raven-worx
I'm using ubuntu now -
Hi,
It's QSerialPortInfo.
-
And what is the error ?
-
@JKSH said in [PLEASE HELP] how to make a barcode receiver?:
Qt Serial Port works with serial ports. A USB port is not a serial port.
thats not true. Of course QtSerialPort works with USB.
USB = Universal Serial BusThe code above i've posted definitively works with a USB Barcode scanner and i used it myself already.
@raven-worx said in [PLEASE HELP] how to make a barcode receiver?:
thats not true. Of course QtSerialPort works with USB.
USB = Universal Serial BusWhat? QtSerialPort works only with serial ports. It has nothing common with USB... Please don't confuse peoples. ;)
-
i dosn't do any thing it always execute "else"
QSerialPort::SerialPortError(DeviceNotFoundError)@davidlabib said in [PLEASE HELP] how to make a barcode receiver?:
QSerialPort::SerialPortError(DeviceNotFoundError)
Well, that means your program can't find a port called COM4. Read the comments in @raven-worx's code and think about what they are asking you to do.
What is the name of the port that your scanner is connected to? https://www.cyberciti.biz/faq/find-out-linux-serial-ports-with-setserial/
@raven-worx said in [PLEASE HELP] how to make a barcode receiver?:
The code above i've posted definitively works with a USB Barcode scanner and i used it myself already.
My apologies; I didn't read the codes or think of the scenario that @mrjj highlighted in his last post.
If the barcode scanner implements RS232-over-USB, then you're right -- Qt Serial Port can indeed work with the scanner via the USB port.
QtSerialPort works with USB.
USB = Universal Serial BusEven though they both have "serial" in their names, Universal Serial Bus is completely unrelated to old-school serial ports. The term "serial port" usually refers to an RS-232 port: https://en.wikipedia.org/wiki/Serial_port
A USB device can be programmed to emulate serial port comms, but these are the minority. You cannot, for example, use Qt Serial Port to read your USB keyboard.
-
@JKSH i didn't worked
i tried form com 1 to com 18
non of them worked@davidlabib said in [PLEASE HELP] how to make a barcode receiver?:
@JKSH i didn't worked
i tried form com 1 to com 18
non of them workedWhat is the name of the port that your scanner is connected to? COMX is a Windows name. Linux names are different.
Read https://www.cyberciti.biz/faq/find-out-linux-serial-ports-with-setserial/ to find the name on your Ubuntu machine.
-
same error
i tried from ttyS0 to ttyS5 didn't work -
same error
i tried from ttyS0 to ttyS5 didn't work@davidlabib said in [PLEASE HELP] how to make a barcode receiver?:
same error
i tried from ttyS0 to ttyS5 didn't workYou didn't answer my question. What is the name of the port that your scanner is connected to?
Also, what does
QSerialPortInfo::availablePorts()give you? http://doc.qt.io/qt-5/qserialportinfo.html#availablePorts -
@davidlabib said in [PLEASE HELP] how to make a barcode receiver?:
same error
i tried from ttyS0 to ttyS5 didn't workYou didn't answer my question. What is the name of the port that your scanner is connected to?
Also, what does
QSerialPortInfo::availablePorts()give you? http://doc.qt.io/qt-5/qserialportinfo.html#availablePorts -
@JKSH ok i could find the right port and passed from
if( port->open(QSerialPort::ReadOnly) )now I'm stuck on
if( !port->bytesAvailable() ) return;it always return
witch mean no bytes is available@davidlabib said in [PLEASE HELP] how to make a barcode receiver?:
now I'm stuck on
if( !port->bytesAvailable() ) return;it always return
witch mean no bytes is availableDid you choose the correct settings? How is your scanner configured for the following?
- Baud rate
- Parity
- Data bits
- Stop bits
- Flow control
-
@JKSH
Baud rate 115200@davidlabib
I guess you don't have permission to use the serial port.
Please type:
ls -l /dev/<your-serial-port-name>in a terminal and post the output here. -
@aha_1980 yes i don't have
but i use sudo -
@davidlabib Better add your user to the group
dialoutand reboot your computer.Of course
sudoworks, but may give new problems.As @JKSH wrote, not only baudrate is important.
I'd suggest to use a terminal program first to verify your scanner works correctly. Then use the same parameters for your code.
