Displaying up to date input signals with tkinter GUI

Question

python 2.7

I'm using a raspberry pi to monitor some digital input signals as an hobby project. I want to have a large display that shows the accumulated values and updates them with global variables that will keep track of the input signals. I'm going to be using push buttons on a breadboard for now so I tried to use a holding variable to keep the counters from incrementing every cycle. I am very new to Python as I'm sure this is obvious so please keep it simple if possible. I am calling one input PE_MATTRESSES, another PE_COMBINED, and the other RESET, I want to display a third value that subtracts PE_MATTRESSES from PE_COMBINED. Of course RESET will zero everything..

My pseudo code though process is:

establish I/O and global variables
create GUI
while 1
-- look at I/O
-- update global variables
-- update labels to display them
-- loop

My code is as follows:

import Tkinter as tk
import tkFont
import time
import RPi.GPIO as GPIO


GPIO.setmode(GPIO.BCM)
GPIO.setup(17, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(21, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(22, GPIO.IN, pull_up_down=GPIO.PUD_UP)


PE_MATTRESS = GPIO.input(17)
PE_MATTRESS_LATCH = 0
PE_MATTRESS_ACCUMULATOR = 0
PE_COMBINED = GPIO.input(21)
PE_COMBINED_LATCH = 0
PE_COMBINED_ACCUMULATOR = 0
BOXSPRING_ACCUMULATOR = 0
BOXSPRING_ACCUMULATOR = PE_COMBINED_ACCUMULATOR - PE_MATTRESS_ACCUMULATOR 
RESET = GPIO.input(22)



class App:
    def __init__(self):
        root=tk.Tk()
        # create a custom font
        self.customFont = tkFont.Font(family="Helvetica", size=117)


        # create widgets 

        label1 = tk.Label(root, text="MATTRESSES: %s" % PE_MATTRESS_ACCUMULATOR , font=self.customFont)
        label1.pack()

        spacer1 = tk.Label(root, text="", font=self.customFont)
        spacer1.pack()

        Quit = tk.Button(root, text="QUIT", command=quit)
        Increment = tk.Button(root, text="Test", command=Inc)
        Quit.pack()
        Increment.pack()


        label2 = tk.Label(root, text="BOXSPRINGS: %s" % BOXSPRING_ACCUMULATOR, font=self.customFont)
        label2.pack()

        spacer2 = tk.Label(root, text="", font=self.customFont)
        spacer2.pack()


        label3 = tk.Label(root, text="      COMBINED: %s" % PE_COMBINED_ACCUMULATOR, font=self.customFont)
        label3.pack()



        root.geometry('1800x1000+0+0')
        root.after(10,Inputs)

        root.mainloop()

    def Inc():

        PE_MATTRESS_ACCUMULATOR = PE_MATTRESS_ACCUMULATOR + 1
    label1.setText("MATTRESSES: %s" % PE_MATTRESS_ACCUMULATOR)
    label2.setText("BOXSPRINGS: %s" % BOXSPRING_ACCUMULATOR)
    label3.setText("      COMBINED: %s" % PE_COMBINED_ACCUMULATOR)

        root.update_idletasks()


    def Inputs():

        if PE_MATTRESS == True and PE_MATTRESS_LATCH == False:
            PE_MATTRESS_ACCUMULATOR = PE_MATTRESS_ACCUMULATOR + 1
            PE_MATTRESS_LATCH = True


        elif PE_MATTRESS == False and PE_MATTRESS_LATCH == True:
            PE_MATTRESS_LATCH = False

        elif PE_COMBINED == True and PE_COMBINED_LATCH == False:
            PE_COMBINED_ACCUMULATOR = PE_COMBINED_ACCUMULATOR + 1
            PE_COMBINED_LATCH = True

        elif PE_COMBINED == False and PE_COMBINED_LATCH == True:
            PE_COMBINED_LATCH = False

        elif RESET == True:
            PE_COMBINED_ACCUMULATOR = 0
            PE_MATTRESS_ACCUMULATOR = 0

app=App()

score 0 · Answer 1 · answered Feb 26 '13 at 13:32

Your pseudo code includes a while 1 loop, but your actual code does not. Also, Inc() is never called. I suggest you add the following lines to the end of Inputs():

self.Inc()
self.root.after(10, self.Inputs)

You'll also have to make root an instance variable, i.e. include self.root = root in __init__() for this to work.

Displaying up to date input signals with tkinter GUI

1 Answers1