import serial
import numpy as np

from matplotlib.figure import Figure
from matplotlib.backends.backend_gtk3cairo import FigureCanvasGTK3Cairo as FigureCanvas
from gi.repository import Gtk
import time
import gobject

class MyWindow(Gtk.ApplicationWindow):
    def __init__(self):

    Gtk.Window.__init__(self, title="Toolbar Example")
        self.set_size_request(700, 500)
    self.box = Gtk.Box(spacing=6, orientation=Gtk.Orientation.VERTICAL)
    self.add(self.box)

    fig = Figure()
    ax = fig.add_subplot(111)
    ax.set_xlim(0, 50)
    ax.set_ylim(0, 20)

    ydata = [0] * 50
    line, = ax.plot(ydata, label='ydata')
    ax.legend()

    f = FigureCanvas(fig)
    self.box.pack_start(f, True, True, 0)

    def update_graph():
        data = ser.readline().rstrip()
        if len(data.split(".")) == 2:
            print data
                ymin = float(min(ydata))-10
                ymax = float(max(ydata))+10
            ax.set_ylim(ymin, ymax)
            ydata.append(data)
            del ydata[0]
            line.set_data(np.arange(len(ydata)), ydata)
            f.draw()
        return True

    gobject.idle_add(update_graph)

ser = serial.Serial('/dev/ttyACM0', 9600)
win = MyWindow()
win.connect("delete-event", Gtk.main_quit)
win.show_all()

Gtk.main()