如何使用在线程之间传递参数的Python线程？

Question

1.总结一下我正在使用的2和运行 Buster的Raspberry 4所遇到的问题。试图限制我的程序从我的Android设备读取传感器数据的速度，该设备使用Socket通过UDP连接发送数据。IE:我把它作为一个小的激光绊线应用程序来构建，为了开始，我想在传感器值降到某个数字以下的时候增加一个计数累加器，指示一个被绊倒的激光。但是，数据读取速度太快，每次传感器级别下降到以下，计数都会增加很多次。如何才能每隔X秒读取一次UDP数据？

2.描述您尝试过的

我尝试过使用

• ()，但从我所读到的情况来看，这是一个阻塞函数，经过测试后，它确实阻止了我的程序在UDP套接字
• 上更新传感器数据--我已经尝试过线程处理，但我不知道如何将传感器数据从一个线程传递到另一个线程。我研究了join()的
• ，但是我看到的技术文档并不是非常初级的

文章，这里推荐建立客户机/服务器接口，但我也不知道如何做到这一点。

3.在适当的情况下，向您展示一些代码，这是我目前在线程解决方案方面的进展。我正在使用名为SensorUDP的安卓应用程序，加上环境光传感器，启动并发送数据，这个程序将读取UDP数据并打印出来。即使没有UDP数据，它仍将运行计数线程。

import socket
from struct import *
import time
import threading

#We have 0-92 over a 1024 byte buffer representing distinct
#sensors being sent over UDP from my android smartphone
#this test program im only pulling byte 56 for Ambient Light sensing
#a laser shining into my phones sensor has 30,000-50,000 lums so anything
#less then that range must mean the laser was tripped


#UDP = SOCK_DGRAM, AF_INET = Internet
UDP_IP = "192.168.1.149" #my rpi4 address
print "Receiver IP: ", UDP_IP
UDP_PORT = 5000 #arbitrary for now but needs to match my androids broadcast
print "Port: ", UDP_PORT
sock = socket.socket(socket.AF_INET, # Internet
                    socket.SOCK_DGRAM) # UDP
sock.bind((UDP_IP, UDP_PORT)) #complete the binding

running = True
count = 0
laserOn = 1000 #using a low lums to test so I dont have to use laser every time
aLight = 0
result_available = threading.Event() #.set() this when the data is recieved
threadTimer = 5

def calcAmbLight():

# Continuously read from the UDP socket
   
    while running:
       
        data, addr = sock.recvfrom(1024) # buffer size is 1024 bytes
        #the data from the app Im using to push the sensor data needs to
        #be unpacked
        aLight = "%.1f" %unpack_from ('!f', data, 56)
        print ("Ambient Light = ", aLight)

def displayCount():
    count = 0
    while running:
        time.sleep(1)
        #how to pass aLight into this thread from the other thread?
        if aLight < laserOn:
            count = count + 1

        print("Current aLight: ",aLight)
        print("Current Count: ", count)
       
if __name__ == '__main__':
              
    #create a basicthread to run calcAmbLight
    calcAmb = threading.Thread(target= calcAmbLight)
    calcAmb.start()
   
    dispCount = threading.Thread(target = displayCount)
    dispCount.start()

Answer 1

当前设置的问题是由于您没有在aLight中声明calcAmbLight()为全局的。将其声明为全局变量应允许此操作。

def calcAmbLight():
    global aLight  # Set the global aLight, instead of a local stack variable

    while running:

        data, addr = sock.recvfrom(1024) # buffer size is 1024 bytes
        #the data from the app Im using to push the sensor data needs to
        #be unpacked
        aLight = "%.1f" %unpack_from ('!f', data, 56)
        print ("Ambient Light = ", aLight)