Raspberry Pi模拟读取

Question

Trying to get the value from Arduino analog pin 0 to be shown as a live value in Tkinter but I'm new to Python.

from Tkinter import *
import RPi.GPIO as GPIO
import time
from pyfirmata import Arduino, util
from time import sleep

board = Arduino ('/dev/ttyUSB0')
GPIO.setwarnings(False)

 ------------------------BOTTOM of the code----------------------------------
 root = Tk()
 frame = Frame(root,height=500,width=500)
 frame.pack()
 root.title("Relay Controle")
 # Raspsberry output pin 11 / relay
 relayButton = Button(root, text="Turn RELAY On", command=relay)
 relayButton.place(x=10,y=2,)
 # Arduino maga: led button
 ledButton = Button(root, text="Turn LED pin 13 On", command=led )
 ledButton.place(x=130,y=2,)
 # value print out
 # Quit Button
 quitButton = Button(root, text="Quit", command=func1 )
 quitButton.place(x=444,y=470,)
 root.mainloop()

Answer 1

root = Tk()
frame = Frame(root,height=500,width=500)
frame.pack()
my_label = StringVariable()
label = Label(frame,textvariable=my_label)
label.pack()
def updateLabel():
    my_label.set("%0.2f"%board.analog[0].read()))
    root.after(100,updateLabel)
root.after(100,updateLabel)
root.title("Relay Controle")

this just calls updateLabel every 100 miliseconds ... updateLabel then refreshes the stringvariable with the new value from the analog read ...

per the docs to read an analog pin

#setup to recieve analog data
it = util.iterator(board)
it.start()
board.analog[0].enable_reporting()
# later to read
board.analog[0].read()

or you get an instance of the analog pin early

analog_0 = board.get_pin(’a:0:i’)
#then later you can read it
analog_0.read()

so my guess is maybe you arenot doing that setup part