a script to plot streaming arduino data on a com port

stream_arduino.py

# -*- coding: utf-8 -*-
"""
stream_arduino.py

Stream data from an arduino on a com port
must run %matplotlib
data comes in this format:
    12351\r\n
Written by: John Franco Saraceno

"""
import datetime
from drawnow import *
import matplotlib.pyplot as plt
import matplotlib
matplotlib.use("tkAgg")
import logging
import numpy as np
import pandas as pd
import serial

#increase font size and weight for easier plot viewing
font = {'font.weight' : 'bold',
        'font.size'   : 24}
#update matplotlib fonts
plt.rcParams.update(**font)
#define the serial port of the arduino
serialPort = '/dev/ttyUSB0'
baudRate = 115200
first_data =[]
second_data =[]
N = 480 #number of points to show
cnt = 0
plt.ion()
datetimes=[]
arduinoData = serial.Serial(serialPort, baudRate)
arduinoData.flushInput()

#Create and configure logger 
logging.basicConfig(filename="datalogfile.log", 
                    format='%(asctime)s %(message)s', 
                    filemode='w')
logger=logging.getLogger() 
logger.setLevel(logging.INFO)

def makeFig(): #Create a function that makes our desired plot
    plt.title('Streaming Radiometer Data')      #Plot the title
    plt.grid(True)                                  #Turn the grid on
    plt.ylabel('W/m2',)                            #Set ylabels
    plt.plot(first_data, 'ro-', label='First parameter',)       #plot the temperature
    plt.legend(loc='upper left')                    #plot the legend


while True: # While loop that loops forever
    try:            
        arduinoString = arduinoData.readline() #read the line of text from the serial port
        #Split the incoming string into an array called dataArray
        dataArray = arduinoString.decode('utf-8').rstrip().lstrip().split(',')   
        first = float(dataArray[0].split(' ')[-1])#Convert first element to floating number and put in temp
        logging.info(str(first))
        # logging.debug("\t")

        first_data.append(first)                     #Build our tempF array by appending temp readings
        drawnow(makeFig)                       #Call drawnow to update our live graph
        plt.pause(.000001)                     #Pause Briefly. Important to keep drawnow from crashing
        cnt = cnt+1
        if(cnt>N):                            #If you have N or more points, delete the first one from the array
            first_data.pop(0)                       #This allows us to just see the last N data points
    except KeyboardInterrupt:
        print("Keyboard Interrupted the datastream")
        break