在tkinter中显示传感器读数

Question

我已经将流量传感器与树莓PI接口。我希望这个读数在tkinter-gui上每秒更新一次。请帮我查一下密码。

import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BOARD)
flowin =7
GPIO.setup(7,GPIO.IN)
rate=0
seconds=0
pulse=550
time_new = 0.0
#numlist=list()
while True:
y=2
time_new = time.time() + 1
rate_cnt = 0
#y=numlist.append(x)
while time.time() <= time_new:
x=GPIO.input(flowin)
if y!=x:
if GPIO.input(flowin)!= 0:
rate+= 1
y=x
seconds+=1
litre=rate/pulse
minutes=seconds/60
flowrate=litre/minutes
#print("flowrate",flowrate)

Answer 1

您可以使用thread读取传感器读数，并更新与tkinterLabel关联的StringVar以显示flowrate。

以下是基于您的代码的示例：

import RPi.GPIO as GPIO
import tkinter as tk
import time
import threading
def read_sensor():
GPIO.setmode(GPIO.BOARD)
flowin =7
GPIO.setup(7,GPIO.IN)
rate=0
seconds=0
pulse=550
time_new = 0.0
#numlist=list()
while True:
y=2
time_new = time.time() + 1
rate_cnt = 0
#y=numlist.append(x)
while time.time() <= time_new:
x=GPIO.input(flowin)
if y!=x:
if GPIO.input(flowin)!= 0:
rate+= 1
y=x
seconds+=1
litre=rate/pulse
minutes=seconds/60
flowrate=litre/minutes
#print("flowrate",flowrate)
# update the tkinter label via StringVar
var.set(f'flowrate: {flowrate:10.2f}')
# create the thread
task = threading.Thread(target=read_sensor, daemon=True)
root = tk.Tk()
var = tk.StringVar()
lbl = tk.Label(root, textvariable=var, width=40, height=5, font=('Consolas', 24, 'bold'))
lbl.pack()
task.start() # start the reading thread
root.mainloop()