Getting started …

How cool would it be take a vintage 1940’s or 1950’s wooden radio and rebuild it as a modern Internet Radio?  That’s the premise I had in mind when I started out on my first Raspberry Pi project.

I used the Adafruit Occidentalis Linux distribution and Adafruit python class for the 16×2 LCD display.

I found a great YouTube tutorial by MeisterVision that covered the basics of the MPC/MPD Linux Music Player really well.

Parts

To build this project, I used:

• Raspberry Pi, model B;
• Adafruit Pi Box enclosure;
• Edimax WiFi dongle;
• Adafruit Pi Cobbler;
• full-size breadboard;
• standard LCD 16×2 + extras;
• push-button switches;
• hookup-wire & staples;
• powered speakers.

I like the Edimax WiFi dongle because it works well and requires low power which makes it perfect for use with the Raspberry Pi without a powered USB hub.

YouTube Video

Here’s a 20-minute YouTube video that describes the radio in detail and demonstrates many of its capabilities, including:

• an LCD display;
• push button control;
• a menu system; and
• a loadable playlist.

The Python Source Code

The source code for this project is in one file called radio.py.  This is my first ever Python program so please forgive any non-pythonesque usage. ☺

#!/usr/bin/python

# radio.py
# January 23, 2013
# Written by Sheldon Hartling for Usual Panic.
# MIT license, all text above must be included in any redistribution
#

#
# based on code from Kyle Prier (http://wwww.youtube.com/meistervision)
# and AdaFruit Industries (https://www.adafruit.com)
# Kyle Prier - https://www.dropbox.com/s/w2y8xx7t6gkq8yz/radio.py
# AdaFruit   - https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code.git, Adafruit_CharLCD
#


# Define GPIO output pins for Radio Controls
PIN_SW1_PREV = 18
PIN_SW2_NEXT = 4

# The Adafruit_CharLCD class controls the LCD display
# using six GPIO output pins:
#  25 = RS (register select)
#  24 = E (enable/strobe)
#  23 = Data bit 4
#  17 = Data bit 5
#  27 = Data bit 6
#  22 = Data bit 7

#dependancies
from Adafruit_CharLCD import Adafruit_CharLCD
from datetime         import datetime
from subprocess       import *
from time             import sleep, strftime
import RPi.GPIO as GPIO

# globals
LCD = Adafruit_CharLCD()
PLAYLIST_MSG = []
STATION = 1
NUM_STATIONS = 0



def main():
   global STATION, NUM_STATIONS, PLAYLIST_MSG

   # Stop music player
   output = run_cmd("mpc stop" )

   # Setup GPIO
   GPIO.setmode(GPIO.BCM)            # Use BCM GPIO numbers
   GPIO.setup(PIN_SW1_PREV, GPIO.IN) # Previous Channel button
   GPIO.setup(PIN_SW2_NEXT, GPIO.IN) # Next Channel button

   # Setup AdaFruit LCD
   LCD.begin(16,2)
   LCD.clear()

# ----------------------------
# LOAD PLAYLIST OF STATIONS
# ----------------------------

   # Startup banner
   LCD.message('Welcome to\nSheldon Radio!')

   # Run shell script to add all stations
   # to the MPC/MPD music player playlist
   output = run_cmd("/home/pi/projects/radio/radio_playlist.sh")

   # Load PLAYLIST_MSG list
   with open ("/home/pi/projects/radio/radio_playlist.sh", "r") as playlist:
      # Skip leading hash-bang line
      for line in playlist:
         if line[0:1] != '#!':  
               break
      # Remaining comment lines are loaded
      for line in playlist:
         if line[0] == "#" :
            PLAYLIST_MSG.append(line.replace(r'\n','\n')[1:-1] + "                ")
   playlist.close()

   sleep(1.5)
   NUM_STATIONS = len(PLAYLIST_MSG)

# ----------------------------
# START THE MUSIC!
# ----------------------------

   # Start music player
   LCD.clear()
   LCD.message(PLAYLIST_MSG[STATION - 1] )
   mpc_play(STATION)
   countdown_to_play = 0
      
   # Main loop
   while True:
      press = read_switches()

      # PREV button pressed
      if(press == 1):
         STATION -= 1
         if(STATION < 1):
            STATION = NUM_STATIONS
         LCD.setCursor(0,0)
         LCD.message(PLAYLIST_MSG[STATION - 1] )
         # start play in 300msec unless another key pressed
         countdown_to_play = 3

      # NEXT button pressed
      if(press == 2):
         STATION += 1
         if(STATION > NUM_STATIONS):
            STATION = 1
         LCD.setCursor(0,0)
         LCD.message(PLAYLIST_MSG[STATION - 1] )
         # start play in 300msec unless another key pressed
         countdown_to_play = 3

      # BOTH buttons pressed together
      if(press == 3):
         menu_pressed()
      # If we haven't had a key press in 300 msec
      # go ahead and issue the MPC command
      if(countdown_to_play > 0):
         countdown_to_play -= 1
         if(countdown_to_play == 0):
            # Play requested station
            mpc_play(STATION)

      delay_milliseconds(100)


def read_switches():

   # Initialize
   got_prev = False
   got_next = False

   # Read switches
   sw1_prev = GPIO.input(PIN_SW1_PREV)
   sw2_next = GPIO.input(PIN_SW2_NEXT)

   # Debounce switches and look for two-button combo
   while(sw1_prev or sw2_next):
      if(sw1_prev):
         got_prev = True
      if(sw2_next):
         got_next = True
      delay_milliseconds(1)
      sw1_prev = GPIO.input(PIN_SW1_PREV)
      sw2_next = GPIO.input(PIN_SW2_NEXT)
   if(got_prev and got_next):
      return 3
   if(got_next):
      return 2
   if(got_prev):
      return 1
   return 0



def delay_milliseconds(milliseconds):
   seconds = milliseconds / float(1000)	# divide milliseconds by 1000 for seconds
   sleep(seconds)



# ----------------------------
# RADIO SETUP MENU
# ----------------------------

MENU_LIST = [
   '1. Display Time \n   & IP Address ',
   '2. Output Audio \n   to HDMI      ',
   '3. Output Audio \n   to Headphones',
   '4. Auto Select  \n   Audio Output ',
   '5. System       \n   Shutdown!    ',
   '6. Exit         \n                ']

def menu_pressed():
   global MENU_LIST

   item = 0
   LCD.clear()
   LCD.message(MENU_LIST[item] )

   keep_looping = True
   while (keep_looping):

      # Wait for a key press
      press = read_switches()

      # PREV button
      if(press == 1):
         item -= 1
         if(item < 0):
            item = len(MENU_LIST) - 1
         LCD.clear()
         LCD.message(MENU_LIST[item] )

      # NEXT button
      elif(press == 2):
         item += 1
         if(item >= len(MENU_LIST)):
            item = 0
         LCD.clear()
         LCD.message(MENU_LIST[item] )

      # BOTH buttons together, This is "Select"
      elif(press == 3):
         keep_looping = False

         # Take action
         if(  item == 0):
            # display time and IP address
            display_ipaddr()
         elif(item == 1):
            # output to HDMI
            output = run_cmd("amixer -q cset numid=3 2")
         elif(item == 2):
            # output to headphone jack
            output = run_cmd("amixer -q cset numid=3 1")
         elif(item == 3):
            # output auto-select
            output = run_cmd("amixer -q cset numid=3 0")
         elif(item == 4):
            #shutdown the system
            output = run_cmd("mpc clear")
            output = run_cmd("sudo shutdown now")
      else:
         delay_milliseconds(100)

   # Restore display
   LCD.clear()
   LCD.message(PLAYLIST_MSG[STATION - 1] )



def display_ipaddr():
   show_wlan0 = "ip addr show wlan0 | cut -d/ -f1 | awk '/inet/ {printf \"w%15.15s\", $2}'"
   show_eth0  = "ip addr show eth0  | cut -d/ -f1 | awk '/inet/ {printf \"e%15.15s\", $2}'"
   ipaddr = run_cmd(show_eth0)
   if ipaddr == "":
      ipaddr = run_cmd(show_wlan0)

   i = 0
   keep_looping = True
   while (keep_looping):

      # Every second, update the time display
      i += 1
      if(i % 10 == 0):
         LCD.setCursor(0,0)
         LCD.message(datetime.now().strftime('%b %d  %H:%M:%S\n'))
         LCD.message(ipaddr)
         #LCD.message('e%15.15s' % ( ipaddr ) )

      # Every 3 seconds, update ethernet or wi-fi IP address
      if(i == 60):
         ipaddr = run_cmd(show_eth0)
         i = 0
      elif(i == 30):
         ipaddr = run_cmd(show_wlan0)

      # Every 100 milliseconds, read the switches
      press = read_switches()
      if(press == 3):
         keep_looping = False
      delay_milliseconds(99)



def run_cmd(cmd):
   p = Popen(cmd, shell=True, stdout=PIPE, stderr=STDOUT)
   output = p.communicate()[0]
   return output



def run_cmd_nowait(cmd):
   pid = Popen(cmd, shell=True, stdout=NONE, stderr=STDOUT).pid



def mpc_play(STATION):
   pid = Popen(["/usr/bin/mpc", "play", '%d' % ( STATION )]).pid



if __name__ == '__main__':
  main()

The Radio Play List

The radio play list / channel line-up is loaded dynamically from a file called radio_playlist.sh.  This file is processed twice by the radio.py program: the first time it is executed as a shell script; and the second time it is read as a text file to load the channel display names.

Here’s the sample file I used in my video …

#! /bin/sh
mpc clear 1>/dev/null

#1 SomaFM, Lush  \nfemale vocals
mpc add http://mp1.somafm.com:8800

#2 CHFX Halifax  \ncountry
mpc add mms://ysj00ms01s0.aliant.net/CHFX

#3 CJCB Sydney   \ncountry
mpc add mms://ysj00ms01s0.aliant.net/CJCB

#4 CHNS Halifax  \nclassic rock
mpc add mms://ysj00ms01s0.aliant.net/CHNS

#5 CFQM Moncton  \nadult Contempora
mpc add mms://ysj00ms01s0.aliant.net/CFQM

#6 CBD  St John  \npublic radio
mpc add mms://ysj00ms01s0.aliant.net/CBD

#7 CJYC St John  \nclassic rock
mpc add mms://ysj00ms01s0.aliant.net/CJYC

#8 CFCY CharTown \ncountry
mpc add mms://ysj00ms01s0.aliant.net/CFCY

#9 CHLQ ChrlTown \nhot AC
mpc add mms://ysj00ms01s0.aliant.net/CHLQ

#10 CHTN ChrlTown\nclassic hits
mpc add mms://ysj00ms01s0.aliant.net/CHTN

#11 CJRW ChrlTown\nclassic rock
mpc add mms://ysj00ms01s0.aliant.net/CJRW

#12 CBC Halifax  \nradio 2
mpc add http://3143.live.streamtheworld.com:80/CBC_R2_HFX_H_SC

#13 CFMJ Toronto \ntalk radio
mpc add http://208.92.54.5:80/CFMJAMAAC_SC

#14 CBC Halifax  \nradio 1
mpc add http://3383.live.streamtheworld.com:80/CBC_R1_HFX_H_SC

Radio Pi Plate.  A Raspberry Pi Internet Radio that uses Adafruit’s RGB Negative 16×2 LCD+Keypad Kit for Raspberry Pi pi plate. (coming soon)