Question

我正在使用树莓派制作简单的门铃报警系统。我做了一个简单的开关，连接到门上。该程序旨在当门打开（HIGH）时通过SMTP向我发送文本，然后在输入返回到低时向我发送另一个文本。

问题在于它为每个警报发送了2个文本。文本上的时间戳显示它们关闭了大约半秒钟。有趣的是，这似乎是pi独有的。我修改了代码，用用户输入的1和0代替GPIO输入，但没有收到重复的文本。下面是我的代码的子集。任何帮助将不胜感激。

另外，电路方面，我正在关闭3,3v PIN 1并在返回PIN 11之前通过1K欧姆电阻运行。

import RPi.GPIO as GPIO
import smtplib
import time
from datetime import datetime, timedelta
from sys import exit

GPIO.setmode(GPIO.BOARD)
GPIO.setup(11, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)

doorstatus = 1

def sendalert(msg):

    server = smtplib.SMTP("smtp.gmail.com", 587)
    server.starttls()
    server.login('MyEmail', 'Password')
    server.sendmail('MyEmail', 'MyNumber@vtext.com', msg)
    server.quit()

    print msg

    return

def doorchange(msg):
    etime = str(datetime.now())
    etime = etime.split(':')
    etime = ",".join(etime)

    message = msg + etime

    sendalert(message)

    return

try:
    while True:

        time.sleep(1)

        if GPIO.input(11) == 1 and doorstatus == 1:
            text = "Alert! Door has been opened. "
            doorchange(text)
            doorstatus = 0
            time.sleep(1)

        elif GPIO.input(11) == 0 and doorstatus == 0:
            text = "Door has been closed. "
            doorchange(text)
            doorstatus = 1
            time.sleep(1)

        else:
            pass

except KeyboardInterrupt:
    GPIO.cleanup()

Answer 1

这看起来像一个弹跳的问题。这意味着当门打开或关闭时，GPIO状态会在稳定之前在0和1之间变化几次。

这可以通过硬件（使用防跳电路，其中包括与电阻并联的电容）或更容易编程来解决。本文档介绍了如何去抖（参见开关去抖部分）：

http://sourceforge.net/p/raspberry-gpio-python/wiki/Inputs/

这当然会让你改变一下你的逻辑：

GPIO.add_event_callback(channel, doorchanged, bouncetime=500)

def doorchanged():
    etime = str(datetime.now())
    etime = etime.split(':')
    etime = ",".join(etime)

    if GPIO.input(11) == 1:
        text = "Alert! Door has been opened. "
    else:
        text = "Alert! Door has been closed. "

    sendalert(text + etime)

Python SMTP在Raspberry Pi上发送重复的电子邮件

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