def __init__(self, **kwargs): super().__init__(**kwargs) btn = Button(text="press 10", pos=(G.xpos[0] - 15, G.btn_y)) btn.size = (80, 50) btn.pin_no = 10 btn.bind(on_press=self.on_event) self.add_widget(btn) btn = Button(text="press 20", pos=(G.xpos[1] - 15, G.btn_y)) btn.size = (80, 50) btn.pin_no = 20 btn.bind(on_press=self.on_event) self.add_widget(btn) Clock.schedule_interval(self.update, 0.05) # 1.0/50.0) 1/50 sec interval