Add Raspberry_Pi_On_Air_Sign (previously a separate repo)

Raspberry_Pi_On_Air_Sign/README.md

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+# Raspberry_Pi_On_Air_Sign
+
+Code to accompany this tutorial:
+https://learn.adafruit.com/internet-streaming-on-air-sign

Raspberry_Pi_On_Air_Sign/onair.py

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+#!/usr/bin/python
+
+# "ON AIR" sign controller for Raspberry Pi.  Polls Ustream and Google+
+# Hangouts for online status, activates PowerSwitch Tail II as needed,
+# turns on lamp.  Requires RPi.GPIO library.
+#
+# Written by Phil Burgess / Paint Your Dragon for Adafruit Industries.
+#
+# Adafruit invests time and resources providing this open source code,
+# please support Adafruit and open-source hardware by purchasing products
+# from Adafruit!
+#
+# Resources:
+# http://www.adafruit.com/products/268
+# http://www.markertek.com/Studio-Gear/Studio-Warning-Lights-Signs.xhtml
+
+import bisect, calendar, json, time, urllib
+import RPi.GPIO as GPIO
+
+pin = 24   # PowerSwitch Tail connects to this GPIO pin
+
+# Ustream settings -----------------------------------------------------------
+# 'uKey' is your Developer API key (request one at developer.ustream.tv).
+# 'uChannel' is Ustream channel to monitor.
+uKey     =  'PUT_USTREAM_DEVELOPER_API_KEY_KERE'
+uChannel =  'adafruit-industries'
+uUrl     = ('http://api.ustream.tv/json/channel/' + uChannel +
+            '/getValueOf/status?key='             + uKey )
+
+# Google+ settings -----------------------------------------------------------
+# 'gKey' is your API key from the Google APIs API Access page (need to switch
+# on G+ on API Services page first).  'gId' is the account ID to monitor (can
+# find this in the URL of your profile page, mild nuisance but ID is used
+# because user name is not guaranteed unique.
+gKey =  'PUT_GOOGLE_API_KEY_HERE'
+gId  =  '112526208786662512291' # Adafruit account ID
+gUrl = ('https://www.googleapis.com/plus/v1/people/' + gId +
+        '/activities/public?maxResults=4&' +
+        'fields=items(title,published),nextPageToken&key=' + gKey)
+gOn  =  'is hanging out'  # This phrase in title indicates an active hangout
+
+# List of starting times (HH:MM) and polling frequency (seconds) -------------
+# This is to provide a more responsive 'on air' switchover time without
+# blowing through search bandwidth limits.  Use more frequent checks during
+# known 'likely to switch' periods, infrequent during 'out of office' times.
+# Currently follows same pattern each day; doesn't have a weekly schedule.
+times = [
+  ("06:00",  60),  # 6am, office hours starting, poll once per minute
+  ("21:25",  10),  # 9:25pm, Show & Tell starting soon, poll 6X/minute
+  ("21:35",  30),  # S&T underway, reduce polling to 2X per minute
+  ("21:55",  10),  # 9:55pm, AAE starting soon, poll 6X/minute again
+  ("22:05",  30),  # AAE underway, slow polling to 2X per minute
+  ("23:10",  60),  # AAE over (plus extra), return to once per minute
+  ("00:00", 900) ] # After midnight, gone home, poll every 15 minutes
+
+def req(url): # Open connection, read and deserialize JSON document ----------
+	connection = urllib.urlopen(url)
+	try:     data = json.load(connection)
+	finally: connection.close()
+	return data
+
+def paginate(pageToken): # ---------------------------------------------------
+	global gOnline, latestPost, timeThreshold
+
+	# Output from Google+ API is paginated, limited to 20 items max.
+	# We can't necessarily read everything in one pass, may need to
+	# make repeated calls passing a "page token" from one to the next.
+	response = req(
+	  (gUrl + '&pageToken=' + pageToken) if pageToken else gUrl)
+	for item in response['items']:
+		utcTime = time.strptime(
+		  item['published'].split('.', 1)[0],
+		  '%Y-%m-%dT%H:%M:%S')
+		seconds = calendar.timegm(utcTime) # UTC -> epoch
+		if seconds > latestPost:
+			# Keep track of time of most recent post.
+			# If the time threshold is more than 24 hours
+			# before this, it can be moved up -- otherwise
+			# searches will eventually reach all the way
+			# back to the last hangout which may be a full
+			# week prior.
+			latestPost = seconds
+			t = latestPost - 60 * 60 * 24
+			if(timeThreshold < t): timeThreshold = t
+		if seconds < timeThreshold:
+			# Time threshold reached, no on-air message
+			# found in any posts newer than the threshold,
+			# no hangout occurring.  Stop search.  Save
+			# time of latest post as new threshold;
+			# no need to search earlier than that for
+			# hangouts, they won't appear retroactively.
+			# (Items are in reverse chronological order.)
+			gOnline       = False
+			timeThreshold = latestPost
+			return None # Stop search; no further pages
+		if gOn in item['title']:
+			# On-air message found!  Set global gOnline
+			# flag, set time threshold to hangout time;
+			# need to keep testing back to this time to
+			# confirm hangout is still running.  (If it
+			# ends, title changes and will no longer
+			# contain the on-air string.  There is no
+			# separate event to indicate end of hangout.)
+			gOnline       = True
+			timeThreshold = seconds
+			return None
+	return response['nextPageToken'] # Continue search on next page
+
+# Startup --------------------------------------------------------------------
+
+GPIO.setwarnings(False)    # Don't bug me about existing pin state
+GPIO.setmode(GPIO.BCM)     # Use Broadcom pin numbers
+GPIO.setup(pin, GPIO.OUT)  # Enable output
+GPIO.output(pin, GPIO.LOW) # Pin off by default
+
+# Convert times[] to a new list with units in integer minutes
+mins = []
+for t in times:
+	x = t[0].split(":")
+	mins.append([(int(x[0]) % 24) * 60 + int(x[1]), t[1]])
+
+mins.sort() # Sort in-place in increasing order
+
+# If first time is not midnight, insert an item there, duplicating the
+# polling frequency of the last item in the list.
+if mins[0][0] > 0: mins.insert(0, [0, mins[len(mins)-1][1]])
+
+timeThreshold = latestPost = 0
+
+while 1: # Main loop ---------------------------------------------------------
+
+	uOnline = gOnline = False
+	startTime = time.time()
+
+	# Ustream broadcast query
+	try:                 uOnline = req(uUrl)['results'] == 'live'
+	except Exception, e: print "Error: {0} : {1}".format(type(e), e.args)
+
+	# G+ hangout query
+	try:
+		pageToken = None
+		while 1:
+			pageToken = paginate(pageToken)
+			if pageToken is None: break
+	except Exception, e: print "Error: {0} : {1}".format(type(e), e.args)
+
+	print 'G+ hangout: ' + ('online' if gOnline else 'offline')
+	print 'Ustream   : ' + ('online' if uOnline else 'offline')
+	GPIO.output(pin, GPIO.HIGH if uOnline or gOnline else GPIO.LOW)
+
+	# Delay before next query
+	try:
+		n = time.time()                      # NAO
+		t = time.localtime(n)                # Local time struct
+		m = t.tm_hour * 60 + t.tm_min        # Convert to minutes
+		i = bisect.bisect(mins, [m, 60]) - 1 # mins[] list index
+		d = mins[i][1] - (n - startTime)     # Time to next poll
+		if d > 0:
+			print 'Waiting ' + str(d) + ' seconds'
+			time.sleep(d)
+	except:
+		time.sleep(60)