Gav's World : Text Viewer : scripts/mpd

File [scripts/mpd_lcd.py]

1	#!/usr/bin/python
2	import smbus
3	import time
4	from mpd import MPDClient
5	import socket
6	# Server for MPD
7	SERVER = "lounge-pi"
8	client = MPDClient() # create client object
9	client.timeout = 10 # network timeout in seconds (floats allowed), default: None
10	client.idletimeout = None # timeout for fetching the result of the idle command is handled seperately, default: None
11	# Host lookup for determining Internet connectivity
12	INET_SERVER = "www.google.com"
13	# Define some device parameters
14	I2C_ADDR = 0x27 # I2C device address
15	LCD_WIDTH = 20 # Maximum characters per line
16	# Define some device constants
17	LCD_CHR = 1 # Mode - Sending data
18	LCD_CMD = 0 # Mode - Sending command
19	LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
20	LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line
21	LCD_LINE_3 = 0x94 # LCD RAM address for the 3rd line
22	LCD_LINE_4 = 0xD4 # LCD RAM address for the 4th line
23	LCD_BACKLIGHT = 0x08 # On
24	#LCD_BACKLIGHT = 0x00 # Off
25	ENABLE = 0b00000100 # Enable bit
26	# Timing constants
27	E_PULSE = 0.0005
28	E_DELAY = 0.0005
29	ZERO_DISP = 3
30	#Open I2C interface
31	#bus = smbus.SMBus(0) # Rev 1 Pi uses 0
32	bus = smbus.SMBus(1) # Rev 2 Pi uses 1
33	def lcd_init():
34	# Initialist display
35	lcd_byte(0x33,LCD_CMD) # 110011 Initialise
36	lcd_byte(0x32,LCD_CMD) # 110010 Initialise
37	lcd_byte(0x06,LCD_CMD) # 000110 Cursor move direction
38	lcd_byte(0x0C,LCD_CMD) # 001100 Display On,Cursor Off, Blink Off
39	lcd_byte(0x28,LCD_CMD) # 101000 Data length, number of lines, font size
40	lcd_byte(0x01,LCD_CMD) # 000001 Clear display
41	time.sleep(E_DELAY)
42	def lcd_byte(bits, mode):
43	# Send byte to data pins
44	# bits = the data
45	# mode = 1 for data
46	# 0 for command
47	bits_high = mode \| (bits &; 0xF0) \| LCD_BACKLIGHT
48	bits_low = mode \| ((bits<<4) &; 0xF0) \| LCD_BACKLIGHT
49	# High bits
50	bus.write_byte(I2C_ADDR, bits_high)
51	lcd_toggle_enable(bits_high)
52	# Low bits
53	bus.write_byte(I2C_ADDR, bits_low)
54	lcd_toggle_enable(bits_low)
55	def lcd_toggle_enable(bits):
56	# Toggle enable
57	time.sleep(E_DELAY)
58	bus.write_byte(I2C_ADDR, (bits \| ENABLE))
59	time.sleep(E_PULSE)
60	bus.write_byte(I2C_ADDR,(bits &; ~ENABLE))
61	time.sleep(E_DELAY)
62	def lcd_string(message,line):
63	# Send string to display
64	message = message.ljust(LCD_WIDTH," ")
65	lcd_byte(line, LCD_CMD)
66	for i in range(LCD_WIDTH):
67	lcd_byte(ord(message[i]),LCD_CHR)
68	def music_details():
69	# Set defaults just in case of errors
70	artist = "Cannot connect to"
71	album = SERVER
72	song = ""
73	length = 0
74	position = 0
75	# Connect to MPD on the server
76	server_up = 1
77	try:
78	client.connect(SERVER, 6600)
79	# Catch socket errors
80	except IOError:
81	server_up = 0
82	print("Car_Server_LCD.py: Could not connect to " + SERVER)
83	# Catch Other MPD Errors
84	except MPDError:
85	server_up = 0
86	print("Car_Server_LCD.py: Could not connect to " + SERVER)
87	if server_up == 1:
88	status = client.status()
89	if status['state'] == "play":
90	position = int(float(status['elapsed']))
91	track = client.currentsong()
92	if len(track) > 0:
93	artist = track['artist']
94	if len(artist) > LCD_WIDTH:
95	artist += " "
96	album = track['album']
97	if len(album) > LCD_WIDTH:
98	album += " "
99	song = track['title']
100	if len(song) > LCD_WIDTH:
101	song += " "
102	length = int(track['time'])
103	else:
104	artist = "Unknown"
105	album = "Unknown"
106	song = "Unknown"
107	# Close and disconnect from the server
108	client.close()
109	client.disconnect()
110	return (artist, album, song, length, position)
111	def format_string(old_string, cur_string, pos):
112	if old_string != cur_string:
113	# We need to reset the position on a new string
114	pos = 0
115	if len(cur_string) > LCD_WIDTH:
116	return cur_string[pos:pos + 20]
117	else:
118	return cur_string
119	def string_pos(cur_string, pos, zero_count):
120	return_pos = 0
121	if (pos + 20) < len(cur_string):
122	if (zero_count < ZERO_DISP) and (pos == 0):
123	zero_count = zero_count + 1
124	else:
125	zero_count = 0
126	return_pos = pos + 1
127	return (return_pos, zero_count)
128	def is_connected(hostname):
129	try:
130	# see if we can resolve the host name -- tells us if there is
131	# a DNS listening
132	host = socket.gethostbyname(hostname)
133	# connect to the host -- tells us if the host is actually
134	# reachable
135	s = socket.create_connection((host, 80), 2)
136	s.close()
137	return True
138	except:
139	pass
140	return False
141	def main():
142	# Main program block
143	# Initialise display
144	lcd_init()
145	# Define old variables to speed up display updates
146	old_artist = ""
147	old_album = ""
148	old_song = ""
149	# Define old displays to speed up display updates
150	disp_artist = ""
151	disp_album = ""
152	disp_song = ""
153	disp_timer = ""
154	# Define the start positions of text strings
155	start_artist = 0
156	start_album = 0
157	start_song = 0
158	# Define the number of times a scrolling message has been at pos=0
159	zero_artist = 0
160	zero_album = 0
161	zero_song = 0
162	# Define an internet check timer
163	inet_timer = 0
164	while True:
165	# Query the MPD server
166	the_music = music_details()
167	artist = the_music[0]
168	album = the_music[1]
169	song = the_music[2]
170	length = the_music[3]
171	position = the_music[4]
172	# Convert the times into HH:SS
173	song_len = time.strftime('%M:%S', time.gmtime(length))
174	song_pos = time.strftime('%M:%S', time.gmtime(position))
175	# Work out if we need to display part of a string
176	artist_string = format_string(old_artist, artist, start_artist)
177	old_artist = artist
178	pos_artist = string_pos(artist, start_artist, zero_artist)
179	start_artist = pos_artist[0]
180	zero_artist = pos_artist[1]
181	album_string = format_string(old_album, album, start_album)
182	old_album = album
183	pos_album = string_pos(album, start_album, zero_album)
184	start_album = pos_album[0]
185	zero_album = pos_album[1]
186	song_string = format_string(old_song, song, start_song)
187	old_song = song
188	pos_song = string_pos(song, start_song, zero_song)
189	start_song = pos_song[0]
190	zero_song = pos_song[1]
191	# Now work out if we have Internet connection, but only
192	# do it every 10 seconds to save bandwidth
193	if time.time() - inet_timer >= 10:
194	if is_connected(INET_SERVER):
195	inet = "*"
196	else:
197	inet = "-"
198	inet_timer = time.time()
199	timer = song_pos + " - " + song_len + " " + inet
200	# Send some test
201	if artist_string != disp_artist:
202	disp_artist = artist_string
203	lcd_string(artist_string, LCD_LINE_1)
204	if album_string != disp_album:
205	disp_album = album_string
206	lcd_string(album_string, LCD_LINE_2)
207	if song_string != disp_song:
208	disp_song = song_string
209	lcd_string(song_string, LCD_LINE_3)
210	if timer != disp_timer:
211	disp_timer = timer
212	lcd_string(timer, LCD_LINE_4)
213	time.sleep(0.2)
214	if __name__ == '__main__':
215	try:
216	main()
217	except KeyboardInterrupt:
218	pass
219	finally:
220	lcd_byte(0x01, LCD_CMD)