import serial
import matplotlib.pyplot as plt
from drawnow import *

values = []

plt.ion()
cnt=0

serialArduino = serial.Serial('COM3', 9600)

def plotValues():
    plt.title('Serial value from Arduino')
    plt.grid(True)
    plt.ylabel('Values')
    plt.plot(values, 'rx-', label='values')
    plt.legend(loc='upper right')

#pre-load dummy data
for i in range(0,26):
    values.append(0)

while True:
    while (serialArduino.inWaiting()==0):
        pass
    valueRead = serialArduino.readline()

    #check if valid value can be casted
    try:
        valueInInt = int(valueRead)
        print(valueInInt)
        if valueInInt <= 1024:
            if valueInInt >= 0:
                values.append(valueInInt)
                values.pop(0)
                drawnow(plotValues)
            else:
                print ("Invalid! negative number")
        else:
            print ("Invalid! too large")
    except ValueError:
        print ("Invalid! cannot cast")