title: Extreme noise when reading usb signal from arduino with python
body: <p>I am trying to collect the temperature from a sensor with arduino and python.
  I'm sending the signal with arduino and getting it with python serial.
  Everything almost works well. But about every 10'nth reading is way off. Measuring a hot water in degress I get something like:</p>
  
  <pre><code>78.375
  78.625
  78.812
  79.000
  79.125
  0.00
  4000
  
  </code></pre>
  
  <p>So it works some of the time, but sometimes it jumps to thousands of degrees, or zero or all the decimals are suspiciously cut like 79.000 degrees.</p>
  
  <p>When i look at the serial monitor in arduino everything is perfect! it never fails. So the error must be with python. But here is very little of the arduino code just for reference:</p>
  
  <pre><code>void setup() {
    Serial.begin(9600);
  }
  ...
  void loop() {
    Serial.print(temp,4);
    Serial.print('\n'); 
  
  }
  </code></pre>
  
  <p>The python code is also kind of long, but i think the error is here, where i grab the data coming from the usb:</p>
  
  <pre><code>import serial
  try:
      ser = serial.Serial('COM3', 9600, timeout=.1)
      time.sleep(2)
      print("Connection to " + 'port' + " established succesfully!\n")
  except Exception as e:
      print(e)
  
  while time.time() &lt; t_end:
      data = ser.read_until().decode('utf-8') 
      if data:
          #store it 
  </code></pre>
  
  <p>So it works but sometimes the data is extremely noisy.
  I would love a tip on what to improve if you have any idea. Thank you.</p>