nightshift

misc/interrupts.py

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+#!/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