With this program you can get the signal of your current WiFi connection. (Only on Linux)

wifisignal.pyw

#!/usr/bin/python
# -*- coding: utf-8 -*-
# Copyright (C) 2012, 2013 Emilio Coppola [email protected]

import commands, sys
from PyQt4 import QtGui, QtCore
class MainWindow(QtGui.QMainWindow): 
    def __init__(self): 
        QtGui.QWidget.__init__(self) 
        quitAction = QtGui.QAction("E&xit", self, shortcut="Ctrl+Q",triggered=QtGui.qApp.quit)
        self.addAction(quitAction)
        self.setContextMenuPolicy(QtCore.Qt.ActionsContextMenu)
        self.setWindowTitle("Wifi Signal") 
        #self.setWindowIcon(QtGui.QIcon(""))  
        self.ProgressBar = QtGui.QProgressBar()
        self.setCentralWidget(self.ProgressBar)

        self.startProgressBar()
        
    def mousePressEvent(self, event):
        if event.button() == QtCore.Qt.LeftButton:
            self.dragPosition = event.globalPos() - self.frameGeometry().topLeft()
            event.accept()
            
    def mouseMoveEvent(self, event):
        if event.buttons() == QtCore.Qt.LeftButton:
            self.move(event.globalPos() - self.dragPosition)
            event.accept()
            
    def update(self):
        p = str(commands.getstatusoutput('iwconfig wlan0 | grep -i --color signal')).split("=")
        d = str(p[2]).split(" ")
        e = int(d[0])+100  
        self.ProgressBar.setValue(e)
                
    def startProgressBar(self):
        timer = QtCore.QTimer(self)
        timer.timeout.connect(self.update)
        timer.start(500)        

app = QtGui.QApplication(sys.argv) 
frame = MainWindow() 
frame.setWindowFlags(frame.windowFlags() | QtCore.Qt.Window)
frame.show() 
sys.exit(app.exec_())