gui_sensor_reading.py

from Tkinter import *
import RPi.GPIO as GPIO
import time

trigger_pin = 18
echo_pin = 23

GPIO.setmode(GPIO.BCM)
GPIO.setup(trigger_pin, GPIO.OUT)
GPIO.setup(echo_pin, GPIO.IN)

def send_trigger_pulse():
    GPIO.output(trigger_pin, True)
    time.sleep(0.0001)
    GPIO.output(trigger_pin, False)

def wait_for_echo(value, timeout):
    count = timeout
    while GPIO.input(echo_pin) != value and count > 0:
        count = count - 1

def get_distance():
    send_trigger_pulse()
    wait_for_echo(True, 10000)
    start = time.time()
    wait_for_echo(False, 10000)
    finish = time.time()
    pulse_len = finish - start
    distance_cm = pulse_len / 0.000058
    distance_in = distance_cm / 2.5
    return (distance_cm, distance_in)

class App:
	
    def __init__(self, master):
        self.master = master
        frame = Frame(master)
        frame.pack()
        label = Label(frame, text='Distance (inches)', font=("Helvetica", 32))
        label.grid(row=0)
        self.reading_label = Label(frame, text='12.34', font=("Helvetica", 110))
        self.reading_label.grid(row=1)
        self.update_reading()

    def update_reading(self):
        cm, inch = get_distance()
        reading_str = "{:.2f}".format(inch)
        self.reading_label.configure(text=reading_str)
        self.master.after(500, self.update_reading)


root = Tk()
root.wm_title('Range Finder')
app = App(root)
root.geometry("400x300+0+0")
root.mainloop()