Newbie 'ish Signals & slots

[MikeP]

I have successfully used signals to communicate between a main module and a GUI module as per the first code snippets, now I need to do the same but in reverse, GUI to main. I have tried several variants of the second code snippets but without success. Does anybody have a definitive working example of how this can be achieved, thanks.

Main module, working version

class measure(QtGui.QMainWindow, Ui_measWindow):

    # create signal for button press processing
    keyUpd = QtCore.pyqtSignal()
    
    def __init__(self):
        super(self.__class__, self).__init__()
        self.ui = Ui_measWindow()
        setConfig()
        self.setupUi(self)
        self._timer = QtCore.QTimer(self)
        self._timer.timeout.connect(self.play)
        self._timer.start(30)
        self._timer = QtCore.QTimer(self)
        self._timer.timeout.connect(self.chkBtns)
        self._timer.start(1000)
        self.update()

GUI module

class Ui_measWindow(object):

    def setupUi(self, measWindow):
        measWindow.setObjectName(_fromUtf8("measWindow"))
        measWindow.resize(xWin, yWin)
        measWindow.setWindowTitle(_fromUtf8("Measure"))
        measWindow.setLocale(QtCore.QLocale(QtCore.QLocale.English, QtCore.QLocale.UnitedKingdom))
        self.centralwidget = QtGui.QWidget(measWindow)
        self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
        self.videoFrame = QtGui.QLabel(self.centralwidget)
        self.videoFrame.setGeometry(QtCore.QRect(0, 0, xCam, yCam))
        self.videoFrame.setObjectName(_fromUtf8("videoFrame"))
        self.txtLabel = QtGui.QLabel(self.centralwidget)
        self.txtLabel.setGeometry(QtCore.QRect(20, 32, 180, 50))
        self.txtLabel.setStyleSheet("QLabel {color : cyan}")
        self.txtLabel.setObjectName(_fromUtf8("txtLabel"))
        self.MainWindow = measWindow
        self.center()

        <SNIP>
        
        measWindow.setCentralWidget(self.centralwidget)
        self.keyUpd.connect(self.updPos)

Main module, non-working version

class Mini1D(QtGui.QMainWindow, Ui_miniWindow):

    self.serUpd.connect(self.serTst)

    def __init__(self):
        super(self.__class__, self).__init__()
        self.ui = Ui_miniWindow()
        setConfig()
        self.setupUi(self)
        self._timer = QtCore.QTimer(self)
        self._timer.timeout.connect(self.play)
        self._timer.start(30)
        start_new_thread(flash,(110.0,10.0))
        self.update()

    def serTst(self):
        # return ID for S2 is export-80 as per GPIO
        # return ID for S0 is -1 although still active
        serial = wpi.serialOpen('/dev/ttyS2', 9600)
        print(str(serial))
        wpi.serialPuts(serial, "test")
        wpi.serialPutchar(serial, 16)
        wpi.serialClose(serial)

GUI module

class Ui_miniWindow(object):

    # create signal for menu processing
    serUpd = QtCore.pyqtSignal()
    
    def setupUi(self, miniWindow):
        miniWindow.setObjectName(_fromUtf8("miniWindow"))
        miniWindow.resize(xWin, yWin)
        miniWindow.setWindowTitle(_fromUtf8("Mini1D"))
        miniWindow.setLocale(QtCore.QLocale(QtCore.QLocale.English, QtCore.QLocale.UnitedKingdom))
        self.centralwidget = QtGui.QWidget(miniWindow)
        self.centralwidget.setObjectName(_fromUtf8("centralwidget"))
        self.videoFrame = QtGui.QLabel(self.centralwidget)
        self.videoFrame.setGeometry(QtCore.QRect(0, 0, xCam, yCam))
        self.videoFrame.setObjectName(_fromUtf8("videoFrame"))
        self.txtLabel = QtGui.QLabel(self.centralwidget)
        self.txtLabel.setGeometry(QtCore.QRect(20, 32, 180, 50))
        self.txtLabel.setStyleSheet("QLabel {color : red}")
        self.txtLabel.setObjectName(_fromUtf8("txtLabel"))
        self.MainWindow = miniWindow
        self.center()

//your code here