title: How to update values from serial port in matplotlib animations?
body: <p>I've been trying to plot serial data from an arduino in real-time using matplotlib's animation function. The data comes from a ntc temperature sensor. The plot I was able to get displays a sigle line all the time, and the line is only translated up or down as the teperature changes. I'd like to know what can I do to view the curves representing the changes in the plot. Here´s the code:</p>
  
  <pre><code>import serial
  from matplotlib import pyplot as plt
  from matplotlib import animation
  import numpy as np
  
  arduino = serial.Serial('COM3', 9600)
  
  fig = plt.figure()
  ax = plt.axes(xlim=(0, 10), ylim=(10, 40))
  line, = ax.plot([], [], lw=2)
  
  def init():
      line.set_data([], [])
      return line,
  
  def animate(i):
      x = np.linspace(0, 10, 1000)
      y = arduino.readline()
      line.set_data(x, y)
      return line,
  
  anim = animation.FuncAnimation(fig, animate, init_func=init, frames=200, interval=20,        blit=False)
  
  plt.show()
  </code></pre>