我正在用覆盆子创建我简单的家庭自动化。现在我可以打开车库门，门和阅读温度。服务器是节点js。现在我想检测车库门何时打开。我认为使用微动开关，但是如何检测何时被按下的最佳方式？ python脚本中的无限循环？一个投票脚本？你能帮助我吗？谢谢
基本上你正在寻找的是实现GPIO中断，你需要的只是RPi.GPIO模块。
但是在RPi.GPIO模块描述中，有一个警告：
请注意，此模块不适用于实时或时序关键应用程序。这是因为你无法预测Python什么时候会忙于垃圾收集。它也在Linux内核下运行，它不适合实时应用程序 - 它是多任务操作系统，而另一个进程可能优先于CPU，从而导致程序抖动。如果您追求真正的实时性能和可预测性，那就给自己买个Arduino吧！
我找到了三种实现任务的方法（我相信应该有更多）：
轮询不断检查某些事情。例如，如果要确保程序尽快对按下按钮做出反应，则可以每秒检查按钮状态大约一万次。如果您需要快速反应，这很好，但它使用了相当多的计算机处理能力。就像您期望交付时无法完全关注一样，您的大部分CPU已用完此轮询。
#!/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
当在第二个线程中检测到事件时，它会将其传回主线程（回调）。我们现在在RPi.GPIO中具有为中断启动新线程的能力，并指定在第二个线程中发生中断时将运行的一组指令（函数）。这是一个线程回调函数。
#!/usr/bin/env python2.7 # script by Alex Eames http://RasPi.tv import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) # GPIO 23 & 24 set up as inputs. One pulled up, the other down. # 23 will go to GND when button pressed and 24 will go to 3V3 (3.3V) # this enables us to demonstrate both rising and falling edge detection GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_UP) GPIO.setup(24, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) # now we'll define the threaded callback function # this will run in another thread when our event is detected def my_callback(channel): print "Rising edge detected on port 24 - even though, in the main thread," print "we are still waiting for a falling edge - how cool?\n" 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" print "You will also need a second button connected so that when pressed" print "it will connect GPIO port 24 (pin 18) to 3V3 (pin 1)" raw_input("Press Enter when ready\n>") # The GPIO.add_event_detect() line below set things up so that # when a rising edge is detected on port 24, regardless of whatever # else is happening in the program, the function "my_callback" will be run # It will happen even while the program is waiting for # a falling edge on the other button. GPIO.add_event_detect(24, GPIO.RISING, callback=my_callback) try: print "Waiting for falling edge on port 23" GPIO.wait_for_edge(23, GPIO.FALLING) print "Falling edge detected. Here endeth the second lesson." except KeyboardInterrupt: GPIO.cleanup() # clean up GPIO on CTRL+C exit GPIO.cleanup() # clean up GPIO on normal exit
实际上，我们并没有做很多与上次非常不同的事情，除了现在还有更多。我们将添加另一个按钮和另一个与第一个相同的线程回调函数（但在不同的GPIO端口上）。这只是为了表明您可以在一个程序中执行多个线程回调。在那之后，你的想象力是极限。 （实际上，GPIO端口的数量可能是限制。）
#!/usr/bin/env python2.7 # script by Alex Eames http://RasPi.tv # http://RasPi.tv/how-to-use-interrupts-with-python-on-the-raspberry-pi-and-rpi-gpio-part-3 import RPi.GPIO as GPIO GPIO.setmode(GPIO.BCM) # GPIO 23 & 17 set up as inputs, pulled up to avoid false detection. # Both ports are wired to connect to GND on button press. # So we'll be setting up falling edge detection for both GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_UP) GPIO.setup(17, GPIO.IN, pull_up_down=GPIO.PUD_UP) # GPIO 24 set up as an input, pulled down, connected to 3V3 on button press GPIO.setup(24, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) # now we'll define two threaded callback functions # these will run in another thread when our events are detected def my_callback(channel): print "falling edge detected on 17" def my_callback2(channel): print "falling edge detected on 23" 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" print "You will also need a second button connected so that when pressed" print "it will connect GPIO port 24 (pin 18) to 3V3 (pin 1)\n" print "You will also need a third button connected so that when pressed" print "it will connect GPIO port 17 (pin 11) to GND (pin 14)" raw_input("Press Enter when ready\n>") # when a falling edge is detected on port 17, regardless of whatever # else is happening in the program, the function my_callback will be run GPIO.add_event_detect(17, GPIO.FALLING, callback=my_callback, bouncetime=300) # when a falling edge is detected on port 23, regardless of whatever # else is happening in the program, the function my_callback2 will be run # 'bouncetime=300' includes the bounce control written into interrupts2a.py GPIO.add_event_detect(23, GPIO.FALLING, callback=my_callback2, bouncetime=300) try: print "Waiting for rising edge on port 24" GPIO.wait_for_edge(24, GPIO.RISING) print "Rising edge detected on port 24. Here endeth the third lesson." except KeyboardInterrupt: GPIO.cleanup() # clean up GPIO on CTRL+C exit GPIO.cleanup() # clean up GPIO on normal exit
希望这一系列的教程能帮助你更好地理解Raspberry Pi GPIO中断，但我建议对Arduino进行一些研究，或者至少在C或C ++这样的低级语言中，你可以找到great tutorial on interrupts there。
你也可以加入qazxsw poi，也许你会在那里找到更多的帮助。