title: Change QLCDNumber colour when a specific Value is read using pyqt5
body: <p>I have a code which reads sensor data and outputs it to a LCD number I am using python3 and pyqt5. </p>
  
  <p>Now What i've been tyring to do with no luck is change the background colour of the LCD number when it reaches a certain value. e.g. when the value falls below 100 the background of the LCD widget is red or an image appears saying too low, if it is between 100-300 it is green and over 300 it goes red again. I hope this makes sense, does anyone know how I can achieve this using pyqt5?</p>
  
  <p>here are the relevant segments of my code for the LCD Number</p>
  
  <pre><code>class Worker(QtCore.QThread):
      valueFound = QtCore.pyqtSignal(int, name="valueFound")
  </code></pre>
  
  <p>...</p>
  
  <pre><code>def run(self):
          while self.runFlag:
              self.valueFound.emit(self.Pressure_Reading())
  </code></pre>
  
  <p>...</p>
  
  <pre><code>self.worker = Worker(self)
  self.worker.valueFound.connect(self.OnValueFound)
  </code></pre>
  
  <p>....</p>
  
  <pre><code>def OnValueFound(self, value):
          self.ui.lcdNumber.display(value)
  </code></pre>