FROM ARDUINO TO MATPLOTLIB

http://www.toptechboy.com/tutorial/python-with-arduino-lesson-11-plotting-and-graphing-live-data-from-arduino-with-matplotlib/

FROM ARDUINO YUN SIDE

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#include "Wire.h"    // imports the wire library for talking over I2C #include "Adafruit_BMP085.h"  // import the Pressure Sensor Library Adafruit_BMP085 mySensor;  // create sensor object called mySensor   float tempC;  // Variable for holding temp in C float tempF;  // Variable for holding temp in F float pressure; //Variable for holding pressure reading   void setup(){ Serial.begin(115200); //turn on serial monitor mySensor.begin();   //initialize mySensor }   void loop() { tempC = mySensor.readTemperature(); //  Be sure to declare your variables tempF = tempC*1.8 + 32.; // Convert degrees C to F pressure=mySensor.readPressure(); //Read Pressure     Serial.print(tempF); Serial.print(" , "); Serial.println(pressure); delay(250); //Pause between readings. }

FROM PYTHON 2.7 SIDE
import serial # import Serial Library
import numpy  # Import numpy
import matplotlib.pyplot as plt #import matplotlib library
from drawnow import *

tempF= []
pressure=[]
arduinoData = serial.Serial('COM8', 9600) #Creating our serial object named arduinoData
plt.ion() #Tell matplotlib you want interactive mode to plot live data
cnt=0

def makeFig(): #Create a function that makes our desired plot
    plt.ylim(80,90)                                 #Set y min and max values
    plt.title('My Live Streaming Sensor Data')      #Plot the title
    plt.grid(True)                                  #Turn the grid on
    plt.ylabel('Temp F')                            #Set ylabels
    plt.plot(tempF, 'ro-', label='Degrees F')       #plot the temperature
    plt.legend(loc='upper left')                    #plot the legend
    plt2=plt.twinx()                                #Create a second y axis
    plt.ylim(93450,93525)                           #Set limits of second y axis- adjust to readings you are getting
    plt2.plot(pressure, 'b^-', label='Pressure (Pa)') #plot pressure data
    plt2.set_ylabel('Pressrue (Pa)')                    #label second y axis
    plt2.ticklabel_format(useOffset=False)           #Force matplotlib to NOT autoscale y axis
    plt2.legend(loc='upper right')                  #plot the legend
    

while True: # While loop that loops forever
    while (arduinoData.inWaiting()==0): #Wait here until there is data
        pass #do nothing
    arduinoString = arduinoData.readline() #read the line of text from the serial port
    dataArray = arduinoString.split(',')   #Split it into an array called dataArray
    temp = float( dataArray[0])            #Convert first element to floating number and put in temp
    P =    float( dataArray[1])            #Convert second element to floating number and put in P
    tempF.append(temp)                     #Build our tempF array by appending temp readings
    pressure.append(P)                     #Building our pressure array by appending P 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>50):                            #If you have 50 or more points, delete the first one from the array
        tempF.pop(0)                       #This allows us to just see the last 50 data points
        pressure.pop(0)