import serial
import numpy as np
from matplotlib import pyplot as plt
ser = serial.Serial('/dev/tty.usbserial-FT9MHVRX', 115200)

plt.ion() # set plot to animated

plt.ylabel('Temperature C')
plt.xlabel('Time')
ydata = [0] * 200
ax1=plt.axes()

# make plot
line, = plt.plot(ydata)
plt.ylim([10,40])

# start data collection
while True:
    data = ser.readline().rstrip() # read data from serial
                                   # port and strip line endings
    if len(data.split(".")) == 2:
        ymin = float(min(ydata))-10
        ymax = float(max(ydata))+10
        plt.ylim([ymin,ymax])
        ydata.append(data)
        del ydata[0]
        line.set_xdata(np.arange(len(ydata)))
        line.set_ydata(ydata)  # update the data
        plt.draw() # update the plot
        plt.pause(1)