radio.py

#!/usr/bin/python
import time
import os
import shlex
import re
import socket

from time import sleep
from subprocess import Popen, PIPE
from Adafruit_CharLCDPlate import Adafruit_CharLCDPlate

stationFilename = "stations.txt"
startPlayerCommand = "mplayer -cache-min 2 "  #minimum cache before start is 2% to get started quickly. 1% fails sometimes.
startPlayerSuffixCommand = " </dev/null >/dev/null 2>&1 &"  #redirect to /dev/null as mplayer requires writing to stdout
killPlayerCommand = "killall mplayer"
#Headphone can be replaced by "PCM" if you use the native Raspberry Pi audio out
getMixerCommand = "amixer sget Headphone"
setVolumeCommand = "amixer -q set Headphone "
toggleMuteCommand = "amixer -q set Headphone toggle"
findVolumeRegex = ".*Playback (.*)\[(.*)%\] \[(.*)\] \[(.*)\]"


regex = re.compile(findVolumeRegex)

stationsList = []
lcd = Adafruit_CharLCDPlate()
stationIndex = 2  #I want to play my third station as default
numStations = None

#16 columns, 2 rows
lcd.begin(16, 2)
lcd.clear()


stationsFile = open(stationFilename, 'r')
lines = stationsFile.read().splitlines()
stationsFile.close()

numStations = len(lines)

for line in lines:
    splitLine = line.split(" | ")
    stationsList.append(splitLine)


def getTime():
  return int(round(time.time() * 1000))

def getStdout(cmd):
    args = shlex.split(cmd)
    proc = Popen(args, stdout=PIPE, stderr=PIPE, shell=True)
    out, err = proc.communicate()
    return out

def getVolume():
  amixerOutput = getStdout(getMixerCommand)
  r = regex.search(amixerOutput)
  volume = r.groups()[1]
  active = r.groups()[3]
  return volume, active

def setVolumePercent(newVolume):
  setVolumeStr = setVolumeCommand + str(newVolume) + "%"
  os.system(setVolumeStr)

def toggleMute():
  os.system(toggleMuteCommand)

def refreshLCD():

  volumePercent, soundStatus = getVolume()
  textToShow = stationsList[stationIndex][0] + "\n" + "Volume: "

  if soundStatus == 'on':
    textToShow += volumePercent + "%"
  else:
    textToShow += "Muted"

  lcd.clear()
  lcd.message(textToShow)

def setNewVolume(increment):
  global currentVolume
  if increment:
    currentVolume += 1
  else:
    currentVolume -= 1
  
  if currentVolume > 100:
    currentVolume = 100

  elif currentVolume < 0:
    currentVolume = 0

  setVolumePercent(currentVolume)

def goToStation():
  os.system(killPlayerCommand)
  nextStationCommand = startPlayerCommand + stationsList[stationIndex][1] + startPlayerSuffixCommand
  print nextStationCommand
  os.system(nextStationCommand)

def setNextStation(increment):
  global stationIndex
  if increment:
    stationIndex += 1
  else:
    stationIndex -= 1

  stationIndex %= numStations
  goToStation()


def getIPAddress():
  return socket.gethostbyname(socket.gethostname())

def showIPAddress():
  ipAddr = getIPAddress()
  lcd.clear()
  lcd.message(ipAddr)


goToStation()


currentVolume = int(getVolume()[0])

previousPressedTime = getTime()
refreshLCD()


while True:
    time.sleep(0.1) #To debounce and prevent excessive CPU use
    if lcd.buttonPressed(lcd.LEFT) and lcd.buttonPressed(lcd.RIGHT):
      showIPAddress()
    elif lcd.buttonPressed(lcd.UP):
      setNewVolume(True)
      refreshLCD()
    elif lcd.buttonPressed(lcd.DOWN):
      setNewVolume(False)
      refreshLCD()
    elif lcd.buttonPressed(lcd.SELECT):
      toggleMute()
      refreshLCD()
    elif lcd.buttonPressed(lcd.LEFT):
      setNextStation(False)
      refreshLCD()
    elif lcd.buttonPressed(lcd.RIGHT):
      setNextStation(True)
      refreshLCD()