Published April 3, 2017

Streaming Internet Radio Based on Raspberry Pi

Streaming Audiostreams from the internet using a Raspberry Pi and HiFiBerry AMP+ and a custom LCD and 6 button interface.

IntermediateWork in progress2 hours21,100

Streaming Internet Radio Based on Raspberry Pi

Things used in this project

Hardware components

Raspberry Pi 3 Model B

HiFiBerry AMP+

Resistor 10k ohm

SparkFun Pushbutton switch 12mm

Adafruit Standard LCD - 16x2 White on Blue

Single Turn Potentiometer- 10k ohms

Software apps and online services

Raspberry Pi Raspbian

Python

Hand tools and fabrication machines

Soldering iron (generic)

MultiMeter

Story

I was looking for a fun project to create with one of the first Raspberry Pi's I ever got. I soon realized the potential of the development board, but was long searching for a really nice project. I came across a YouTube post from Kyle Prier where he created a proof of concept streaming internet radio.

The inspiration for this project

While recreating the project I soon realized that some of the code could be improved, for example shorten the initial loop, refactor the LCD code into its own library and use interrupts to check for button presses.

When the project became more and more stable I began to research the way to package it into a real device instead of having to use the breadboard permanently. That gave rise to research speakers, drivers and the way to construct them from scratch. I wrote a program to calculate the optimum volume for the speaker enclosure and how to vary width, breadth and depth while keeping the fixed volume (something I did not find the tools for online).

The Sketchup design for the device

I had to learn how to use SketchUp and Fritsing to create a design and the design for the PCB that would connect all the parts in stead of the breadboard.

Fritzing breadboard layout

Electronic schematics

The eventual implementation of the schematic

I created a carboard prototype and am on the verge of actually creating the device in wood.

Cardboard prototype.

The completed wiring excluding the buttons. It works!

Completed buttons, all pass quality testing.

Wednesday 3rd of May 2017

I am finding that the display is somewhat unstable. After booting the display functions as expected, but after one or two button presses (no matter what button) I am starting to see garbage on the display. I have two of the same displays in my possession and I am seeing this issue with both displays, leading me to believe that this is a software issue.

I 'reverse engineered' the LiquidCrystal.h library that is used in combination with an Arduino, seeing as the display works correctly on that platform and found that the timings need finetuning. I changed and added some extra timing settings in the code and rewrote the init and bitwrite functions in the LCDLib.py module.

I need to test it still, but will post on my progress.

Will keep you all posted!

Code

#!/usr/bin/python
#
# Script for Raspberry Pi Internet Radio
# 
# Author: Kyle Prier
# Site: http://wwww.youtube.com/meistervision
# 
# LCD author : Matt Hawkins
# Site   : http://www.raspberrypi-spy.co.uk/
#
# Rework: Solino C. de Backlight
# Added functionality for Volume UP and DOWN, Shutdown
# Added interrupts for reading buttons
#
# Date   : 26-03-2017
#

# The wiring for the LCD is as follows:
# 1 : GND
# 2 : 5V
# 3 : Contrast (0-5V)*
# 4 : RS (Register Select)
# 5 : R/W (Read Write)       - GROUND THIS PIN! We do not want the LCD to send anything to the Pi @ 5v
# 6 : Enable or Strobe
# 7 : Data Bit 0             - NOT USED
# 8 : Data Bit 1             - NOT USED
# 9 : Data Bit 2             - NOT USED
# 10: Data Bit 3             - NOT USED
# 11: Data Bit 4
# 12: Data Bit 5
# 13: Data Bit 6
# 14: Data Bit 7
# 15: LCD Backlight +5V
# 16: LCD Backlight GND (Red, Optional)
# 17: LCD Backlight GND (Green, Optional)
# 18: LCD Backlight GND (Blue, Optional)

# import
import RPi.GPIO as GPIO
import time
import os
import alsaaudio
import LCDLib
import sys

# Create Audio Object
mixer = alsaaudio.Mixer()
mixer.setvolume(50)
currentvol = mixer.getvolume()
currentvol = int(currentvol[0])

# GPIO Setup

# Define GPIO for Radio Controls
NEXT = 8
PREV = 7
VOLUP = 6
VOLDOWN = 5
SHUTDOWN = 13

GPIO.setwarnings(False)  # Mute warnings
GPIO.setmode(GPIO.BCM)  # Use BCM GPIO numbers

GPIO.setup(NEXT, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)  # Next Channel button
GPIO.setup(PREV, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)  # Previous Channel button
GPIO.setup(VOLUP, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)  # Volume Up
GPIO.setup(VOLDOWN, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)  # Volume Down
GPIO.setup(SHUTDOWN, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)  # Bring OS down

#Initialize display
LCDLib.lcd_init()

#define volume function
def change_volume(volume):
	global currentvol
	if (currentvol <= 100) and (currentvol >= 0):
	    LCDLib.lcd_init()
	    newVol = currentvol + volume
	    mixer.setvolume(newVol)
	    currentvol = mixer.getvolume()
	    currentvol = int(currentvol[0])
	    displayvolume = "Volume: " + str(newVol)
	    LCDLib.lcd_display("",1,displayvolume,2,"",1,"",1)
	    time.sleep(2)
	    LCDLib.lcd_clear()
	    display_current_station()

def display_current_station():
	f = os.popen("mpc current")
	station = ""
	for i in f.readlines():
	    station += i
	# Send some text
	LCDLib.lcd_display(station,1,"",2,"",1,"",1)

def callback_next(channel):
	os.system("mpc next")
	time.sleep(1)
	os.system("mpc play")
	display_current_station()
	
def callback_prev(channel):
	os.system("mpc prev")
	time.sleep(1)
	os.system("mpc play")
	display_current_station()

def callback_volup(channel):
	change_volume(5)

def callback_voldown(channel):
	change_volume(-5)

def callback_shutdown(channel):
	LCDLib.lcd_display("",1,"System shutting down!",2,"",1,"",1)
	time.sleep(2)
	GPIO.cleanup()
	os.system("sudo shutdown -H now")
	sys.exit(0)

GPIO.add_event_detect(NEXT, GPIO.RISING, callback=callback_next, bouncetime=300)
GPIO.add_event_detect(PREV, GPIO.RISING, callback=callback_prev, bouncetime=300)
GPIO.add_event_detect(VOLUP, GPIO.RISING, callback=callback_volup, bouncetime=300)
GPIO.add_event_detect(VOLDOWN, GPIO.RISING, callback=callback_voldown, bouncetime=300)
GPIO.add_event_detect(SHUTDOWN, GPIO.RISING, callback=callback_shutdown, bouncetime=300)

#Main program block
def main():
	LCDLib.lcd_display("Raspberry Pi", 2, "Internet Radio", 2, "by", 2, "Solino de Baay", 2)
	time.sleep(4)
	os.system("mpc play")
	while 1:
		LCDLib.lcd_clear()
		display_current_station()
		time.sleep(20)

if __name__ == '__main__':
    main()

LCDLibrary

Python

The initial code had all the LCD driving code incorporated in the setup. There was, however, a lot of code repetition. I refactored the LCD code out of the original script into a library which abstracted all the LCD calls into one simple function that can be called from the main program.
The LCD's are prone to have timing issues and you may need to fidget with the timings for the E_PULSE and E_DELAY variables. If you have questions or improvements to the code, let me know.

The eventual plan is to rewrite the main program to use the AdaFruit LCD Library which seems to be more comprehensive and contains a lot more functionality.

#!/usr/bin/python
#
# Script for Raspberry Pi LCD Library
# 
# Author: Solino de Baay
# Site: http://wwww.de-baay.nl
# 
# LCD author : Matt Hawkins
# Site   : http://www.raspberrypi-spy.co.uk/
#
# Date   : 09/02/2017
#

# The wiring for the LCD is as follows:
# 1 : GND
# 2 : 5V
# 3 : Contrast (0-5V)*
# 4 : RS (Register Select)
# 5 : R/W (Read Write)       - GROUND THIS PIN! We do not want the LCD to send anything to the Pi @ 5v
# 6 : Enable or Strobe
# 7 : Data Bit 0             - NOT USED
# 8 : Data Bit 1             - NOT USED
# 9 : Data Bit 2             - NOT USED
# 10: Data Bit 3             - NOT USED
# 11: Data Bit 4
# 12: Data Bit 5
# 13: Data Bit 6
# 14: Data Bit 7
# 15: LCD Backlight +5V
# 16: LCD Backlight GND (Red, Optional)
# 17: LCD Backlight GND (Green, Optional)
# 18: LCD Backlight GND (Blue, Optional)

#import
import RPi.GPIO as GPIO
import time
import os

#GPIO Setup
GPIO.setwarnings(False)  # Mute warnings
GPIO.setmode(GPIO.BCM)  # Use BCM GPIO numbers

# Define GPIO to LCD mapping
LCD_RS = 25
LCD_E  = 24
LCD_D4 = 23
LCD_D5 = 17
LCD_D6 = 27
LCD_D7 = 22

#Configure GPIO Pins
GPIO.setup(LCD_E, GPIO.OUT)  # E
GPIO.setup(LCD_RS, GPIO.OUT) # RS
GPIO.setup(LCD_D4, GPIO.OUT) # DB4
GPIO.setup(LCD_D5, GPIO.OUT) # DB5
GPIO.setup(LCD_D6, GPIO.OUT) # DB6
GPIO.setup(LCD_D7, GPIO.OUT) # DB7

# Define some device constants
LCD_WIDTH = 20    # Maximum characters per line
LCD_CHR = True
LCD_CMD = False
 
# Timing constants
E_PULSE = 0.00010
E_DELAY = 0.00010

# Send text
def lcd_display(line_1, style_1, line_2, style_2, line_3, style_3, line_4, style_4):
  arguments = locals()
  for x in xrange (1, 5):
    outstr = "line_" + str(x)
    outstyle = "style_" + str(x)
    outlcd = "LCD_LINE_" + str(x)
    if outlcd == "LCD_LINE_1":
      outlcd = 0x80
    elif outlcd == "LCD_LINE_2":
      outlcd = 0xC0
    elif outlcd == "LCD_LINE_3":
      outlcd = 0x94
    elif outlcd == "LCD_LINE_4":
      outlcd = 0xD4
    stylex=int(arguments[outstyle])
    lcd_byte(outlcd, LCD_CMD)
    lcd_string(arguments[outstr], stylex)

def lcd_clear():
  lcd_byte(0x01,LCD_CMD)

def lcd_init():
  # Initialise display
  lcd_byte(0x33,LCD_CMD) #initialize display 1
  lcd_byte(0x32,LCD_CMD) #initialize display 2
  lcd_byte(0x28,LCD_CMD) #Function Set 4-bit 2 line 5x7 dots
  lcd_byte(0x0C,LCD_CMD) #Display on  
  lcd_byte(0x06,LCD_CMD) #Entry mode
  lcd_byte(0x01,LCD_CMD) #Clear display   
 
def lcd_string(message,style):
  # Send string to display
  # style=1 Left justified
  # style=2 Centred
  # style=3 Right justified
 
  if style==1:
    message = message.ljust(LCD_WIDTH," ")  
  elif style==2:
    message = message.center(LCD_WIDTH," ")
  elif style==3:
    message = message.rjust(LCD_WIDTH," ")
 
  for i in range(LCD_WIDTH):
    lcd_byte(ord(message[i]),LCD_CHR)
 
def lcd_byte(bits, mode):
  # Send byte to data pins
  # bits = data
  # mode = True  for character
  #        False for command
 
  GPIO.output(LCD_RS, mode) # RS
 
  # High bits
  GPIO.output(LCD_D4, False)
  GPIO.output(LCD_D5, False)
  GPIO.output(LCD_D6, False)
  GPIO.output(LCD_D7, False)
  if bits&0x10==0x10:
    GPIO.output(LCD_D4, True)
  if bits&0x20==0x20:
    GPIO.output(LCD_D5, True)
  if bits&0x40==0x40:
    GPIO.output(LCD_D6, True)
  if bits&0x80==0x80:
    GPIO.output(LCD_D7, True)
 
  # Toggle 'Enable' pin
  time.sleep(E_DELAY)    
  GPIO.output(LCD_E, True)  
  time.sleep(E_PULSE)
  GPIO.output(LCD_E, False)  
  time.sleep(E_DELAY)      
 
  # Low bits
  GPIO.output(LCD_D4, False)
  GPIO.output(LCD_D5, False)
  GPIO.output(LCD_D6, False)
  GPIO.output(LCD_D7, False)
  if bits&0x01==0x01:
    GPIO.output(LCD_D4, True)
  if bits&0x02==0x02:
    GPIO.output(LCD_D5, True)
  if bits&0x04==0x04:
    GPIO.output(LCD_D6, True)
  if bits&0x08==0x08:
    GPIO.output(LCD_D7, True)
 
  # Toggle 'Enable' pin
  time.sleep(E_DELAY)    
  GPIO.output(LCD_E, True)  
  time.sleep(E_PULSE)
  GPIO.output(LCD_E, False)  
  time.sleep(E_DELAY)

Credits

El Condor

1 project • 17 followers

Aspiring artist with a side-job as an IT Admin. Part-time write, poët, tinkerer, inventor. Full-time dreamer.

Thanks to Kyle Prier and Matt Hawkins.

Streaming Internet Radio Based on Raspberry Pi

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Schematics

Electronic schematic

Design

Breadboard view

Code

Core Radio firmware

LCDLibrary

Credits

El Condor

Comments

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Streaming Internet Radio Based on Raspberry Pi

Streaming Internet Radio Based on Raspberry Pi

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Schematics

Electronic schematic

Design

Breadboard view

Code

Core Radio firmware

LCDLibrary

Credits

El Condor

Comments

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