ldr.py

"""
Display Random Data using matplotlib's animation function

forked from:
Author: Mahesh Venkitachalam
Website: electronut.in
"""

import sys
import numpy as np
from time import sleep
from collections import deque
import random

import matplotlib.pyplot as plt 
import matplotlib.animation as animation

    
# plot class
class AnalogPlot:
  # constr
  def __init__(self, maxLen):
      self.ax = deque([0.0]*maxLen)
      self.maxLen = maxLen

  # add to buffer
  def addToBuf(self, buf, val):
      if len(buf) < self.maxLen:
          buf.appendleft(val)
      else:
          buf.popleft()
          buf.append(val)

  # add data
  def add(self, data):
      self.addToBuf(self.ax, data)

  # update plot
  def update(self, frameNum, a0):
      try:
          self.add(random.random()*1023)
          a0.set_data(range(self.maxLen), self.ax)
      except KeyboardInterrupt:
          print('exiting')
      
      return a0, 

      
# main() function
def main():
  # plot parameters
  
  maxLen = 1000
  
  analogPlot = AnalogPlot(maxLen)

  print('plotting data...')

  # set up animation
  fig = plt.figure()
  ax = plt.axes(xlim=(0, maxLen), ylim=(0, 1023))
  a0, = ax.plot([], [])
  anim = animation.FuncAnimation(fig, analogPlot.update, 
                                 fargs=(a0,), 
                                 interval=50)

  # show plot
  plt.show()
  
  print('exiting.')
  

# call main
if __name__ == '__main__':
  main()