Linking Live data from an Arduino to a LCDNumber from pyqt5 with python3.5

Question

I am fairly new to making a GUI. I designed one for a project that I would like to have LCDs update as the data comes in from the Arduino. I am using pyqt5 to convert my Qtd

Answer 1

For the correct operation I have modified the name of some variables because they do not match their use. In order to send information between elements of PyQt it is advisable to use signals and slots, for this you must create a signal in QThread that sends the information that is required to be displayed in the GUI for this we use pyqtSignal() where we indicate the types of parameters that go to send.

class GetData(QThread):
    dataChanged = pyqtSignal(float, float, float, float)
    Distance = 0.5

    def __init__(self, parent=None):
        QThread.__init__(self, parent)

        arduino_ports = [  # automatically searches for an Arduino and selects the port it's on
            p.device
            for p in serial.tools.list_ports.comports()
            if 'Arduino' in p.description
        ]

        if not arduino_ports:
            raise IOError("No Arduino found - is it plugged in? If so, restart computer.")
        if len(arduino_ports) > 1:
            warnings.warn('Multiple Arduinos found - using the first')
        self.Arduino = serial.Serial(arduino_ports[0], 9600, timeout=1)

    def __del__(self):  # part of the standard format of a QThread
        self.wait()

    def run(self):  # also a required QThread function, the working part
        self.Arduino.close()
        self.Arduino.open()

        self.Arduino.flush()
        self.Arduino.reset_input_buffer()
        start_time = time.time()

        while True:
            while self.Arduino.inWaiting() == 0:
                pass
            try:
                data = self.Arduino.readline()
                dataarray = data.decode().rstrip().split(',')
                self.Arduino.reset_input_buffer()
                Force = round(float(dataarray[0]), 3)
                RPM = round(float(dataarray[1]), 3)
                Torque = round(Force * GetData.Distance, 3)
                HorsePower = round(Torque * RPM / 5252, 3)
                Run_Time = round(time.time() - start_time, 3)
                print(Force, 'Grams', ",", RPM, 'RPMs', ",", Torque, "ft-lbs", ",", HorsePower, "hp", Run_Time,
                      "Time Elasped")
                self.dataChanged.emit(RPM, Torque, HorsePower, Run_Time)
            except (KeyboardInterrupt, SystemExit, IndexError, ValueError):
                pass

Qt Designer provides a design, does not provide a widget, for that it is best to create a class inherit from a widget and use the design, create an instance of QThread and connect the dataChanged signal to some slot, and in that slot is where we place the values in the QLCDNumber.

class GUI(QWidget, Ui_DynoTest1):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)
        self.setupUi(self)
        self.thread = GetData(self)
        self.thread.dataChanged.connect(self.onDataChanged)
        self.thread.start()

    def onDataChanged(self, RPM, Torque, HorsePower, Run_Time):
        self.lcdNumber_4.display(RPM)
        self.lcdNumber_5.display(Torque)
        self.lcdNumber_6.display(HorsePower)
        self.lcdNumber_7.display(Run_Time)


if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    Dyno = GUI()
    Dyno.show()
    sys.exit(app.exec_())