当按下按钮时，python 脚本在 Raspberry Pi 上自动运行

Question

网上找不到教程。

当我按下一个按钮时，我想要一些 python 脚本到运行。我不想先在 Raspberry Pi 的终端上运行 python 脚本，然后像一些教程提到的那样等待按钮被按下。我还希望在按下按钮后整个脚本变为运行，而不是我必须在整个脚本持续时间内按下按钮才能变为运行。

基本上，我希望脚本运行无需将 HDMI 显示器或鼠标连接到 Raspberry Pi 或 GUI 东西。只需按下一个按钮。

此外，如果有人有关于如何使用 GPIO 和代码设置按钮的图表，那将非常有帮助。

我该怎么做？？我在上面找不到任何东西，它看起来很简单。

Answer 1

您总是需要一些程序来监控您的输入，无论是来自键盘、鼠标还是连接到 GPIO 的按钮。对于键盘和鼠标，OS 为您提供了此功能。因此，要从 GPIO 引脚触发程序，您需要编写如下脚本：

import RPi.GPIO as GPIO
import time
import subprocess

GPIO.setmode(GPIO.BCM)

GPIO.setup(18, GPIO.IN, pull_up_down=GPIO.PUD_UP)

while True:
    input_state = GPIO.input(18)
    if input_state == False:
        subprocess.call(something)
        # block until finished (depending on application)

这是一个按钮电路（来自this tutorial）

Answer 2

轮询的更有效替代方法是使用中断：

#!/usr/bin/env python2.7  
# script by Alex Eames http://RasPi.tv/  
# http://raspi.tv/2013/how-to-use-interrupts-with-python-on-the-raspberry-pi-and-rpi-gpio  
import RPi.GPIO as GPIO  
GPIO.setmode(GPIO.BCM)  

# GPIO 23 set up as input. It is pulled up to stop false signals  
GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_UP)  

print "Make sure you have a button connected so that when pressed"  
print "it will connect GPIO port 23 (pin 16) to GND (pin 6)\n"  
raw_input("Press Enter when ready\n>")  

print "Waiting for falling edge on port 23"  
# now the program will do nothing until the signal on port 23   
# starts to fall towards zero. This is why we used the pullup  
# to keep the signal high and prevent a false interrupt  

print "During this waiting time, your computer is not"   
print "wasting resources by polling for a button press.\n"  
print "Press your button when ready to initiate a falling edge interrupt."  
try:  
    GPIO.wait_for_edge(23, GPIO.FALLING)  
    print "\nFalling edge detected. Now your program can continue with"  
    print "whatever was waiting for a button press."  
except KeyboardInterrupt:  
    GPIO.cleanup()       # clean up GPIO on CTRL+C exit  
GPIO.cleanup()           # clean up GPIO on normal exit

（来自 http://raspi.tv/2013/how-to-use-interrupts-with-python-on-the-raspberry-pi-and-rpi-gpio）

当按下按钮时，python 脚本在 Raspberry Pi 上自动运行

When press button, python script runs automatically on Raspberry Pi

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button

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