ArduRadio

ArduRadio:
Playing Internet Radio with Arduino
Javier Montaner
montanerj@yahoo.com
@tumaku_

Agenda
Introduction
Bill of Materials
Key Learnings
Project Status & Next Steps

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© Javier Montaner 2012

Introduction

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Internet Radio on Arduino
Exploratory work to understand what can(not) be done with
Arduino and similar HW platforms
Based on commercial Arduino boards and shields: 7
Arduino Mega
Ethernet
MP3
NFC
Final source code will be opened through github

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Project Scope
Build an Arduino-based device that plays internet streaming
radio
Use simple touch user interface (NFC/RFID) to select radio
stations
Learn about open HW
Share results with the community

A similar concept has been explored by Jordi Parra (@zenona)
in its SpotifyBox project: http://postscapes.com/spotify-box

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Bill of Materials (BOM)

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Arduino Mega 2560

256 KB
54 Digital I/O Pins

Can be implemented on Arduino
UNO but memory and available
PINs start being a problem

http://arduino.cc/en/Main/ArduinoBoardMega2560

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Arduino Ethernet Shield

Based on WiznetW5100
10/100 Mb
TCP/IP library
Includes micro-SD card slot
Controlled through SPI

http://arduino.cc/en/Main/ArduinoEthernetShield

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Sparkfun MP3 Player Shield

Based onVS1053B
Plays Ogg Vorbis/MP3/
AAC/WMA/MIDI
3.5mm stereo output jack
Includes micro SD card slot
Controlled through SPI

https://www.sparkfun.com/products/10628

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SeeedStudio NFC Shield

Based on NXP PN532
Suppport Reader, Card
emulation and Peer to Peer
PCB printed antenna
Controlled through
software SPI

http://www.seeedstudio.com/depot/nfc-shield-p-916.html

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Unyka UK-1 Portable Speaker

USB Powered with Lithium Ion
built-in battery (500mAh)
Includes micro SD card slot
USB and 3,5mm audio jack
Volume control
Frequency range: 90Hz -20kHz
Power: 2 watts

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Total Cost of Prototype in €

Component Price
Arduino Mega €41
Ethernet Shield €29
MP3 Shield €32
NFC Shield €24
Speaker €15
Total €141

This cost is not suitable for a commercial product but it is extremely cheap to build a
working prototype
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Where to buy?

I have bought hardware in all these web stores, but there are many
more out there in internet

Adafruit http://www.adafruit.com/
Arduino store http://store.arduino.cc/
Cooking-Hacks http://www.cooking-hacks.com/
SeeedStudio http://www.seeedstudio.com/depot/
Sparkfun Electronics http://www.sparkfun.com/

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Key Learnings

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General
Open HW community is very active
Quality of documentation varies greatly but people are
usually helpful and reactive
Google is a great source of (hidden) information
Arduino is a learning and prototyping tool. There are
definitely more powerful and cheaper platforms but almost
any technology that you can think of has already been
integrated in/through an Arduino shield
There are other HW solutions from alternative vendors for
all the elements in the BOM

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Arduino
I started with Arduino Uno,
but soon ran out of PINs and
memory so I easily moved to
Arduino Mega
Interoperability between
shields usually requires some
rewiring (physical or in
libraries) but no soldering
There is always somebody that
has experienced and solved
your problem. Check arduino
forums and google

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Arduino
Dig into Arduino open libraries to
learn (I did learn a lot about SPI,
registers, interruptions, etc.)
Update the official libraries to add
new functionality. If you mess it
up, you can easily restore them
Arduino IDE is very simple to
start but it becomes too simple
when you want to work on more
complex projects

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Arduino Ethernet Shield
There is an Arduino Ethernet
board that could make the BOM
cheaper
client.print("GET ");
The Ethernet library implements client.print(ndefPath);
TCP/IP stack but not http -> you client.println("
HTTP/1.1");
need to hardcode http protocol client.println("Connection:
Keep-Alive");
yourself client.print("HOST: ");
client.println(ndefServer);
The good point is that the library client.println();
design makes your code
“interoperable” (easily portable)
when you replace Ethernet by
WiFi or GPRS ☺
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MP3 Player Shield
The original library is not fully working
and showed (at least for me) some
interoperability issues. However Bill
Porter (@Bill_Porter) has shared an
excellent library (great to learn about
Arduino interruptions) that works
asynchronously
Another helpful example is available at
Rui’s The Techman blog
The shield itself supports any bitrate but
Arduino speed limits it only to 32kbps
streams. If you try to play higher
bitrates the sound becomes bumpy

http://www.billporter.info/sparkfun-mp3-shield-arduino-library/
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http://supertechman.blogspot.com.es/2010/11/playing-mp3-with-vs1053-arduino-shield.html

NFC Shield
The original library uses its own software
implementation of the SPI protocol.
Unfortunately, it is not compatible with the
Arduino HW library used by Ethernet/MP3
shields. Solution → Use different PINs for
NFC SPI implementation
Alternatively I have created a HW version
of Seeedstudio’s library available at github
The library supports basic RFID
functionality (e.g. it can read MIFARE
Ultralight and Classic tags). However it has
no notion of NFC protocols. If you want to
use NFC formats (i.e. NDEF) you need to
update the library yourself
Although PN532 supports communication
through SPI or I2C, the shield hardwires the
SPI option
https://github.com/jmgjmg/PN532
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NFC Technology
You can use the NFC shield just as a reader of RFID tags. However if you want to interact with
NFC formatted tags, you need to check the NFC specifications
General information and NFC specifications (formats and protocols) can be downloaded from
NFC Forum after agreeing to their terms and conditions. You ca skip the radio layers (the
shield/PN532 chip does the job) but you need the NDEF (NFC Data Exchange Format)
specifications for messages and records
http://www.nfc-forum.org/specs/spec_list/
You also need to understand how NDEF messages are coded in different tags (e.g. I have used
Mifare Ultralight tags and had to follow “NFC Forum Type 2 Tag Operation Specification”)
I found very useful NFC examples and documentation for Android phones. In particular I suggest
reading:
Getting started with NFC on Android by Richard Legget (.net magazine)
http://www.netmagazine.com/tutorials/getting-started-nfc-android
Android API Guide for developers
http://developer.android.com/guide/topics/connectivity/nfc/nfc.html
There are two useful and free applications from NXP in the Android Play Store to read and write
the content of different types of NFC tags:
NFC Tag Info: https://play.google.com/store/apps/details?id=com.nxp.taginfolite
NFC Tag Writer: https://play.google.com/store/apps/details?id=com.nxp.nfc.tagwriter

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NDEF Formatted Mifare Ultralight Tag
Block Binary content
[00] * XX:XX:XX:XX (UID0-2, BCC0)
[01] * XX:XX:XX:XX (UID3-6)
[02] . XX 48 00:00 (BCC1, INT, LOCK0-1)
[03] . E1:10:06:00 (OTP0-3)
[04] . 03 28 D1 01 |.(..|
[05] . 24 55 03 73 |$U.s|
[06] . 74 72 65 61 |trea|
[07] . 6D 31 2E 72 |m1.r|
[08] . 61 64 69 6F |adio|
[09] . 6D 6F 6E 69 |moni|
[0A] . 74 6F 72 2E |tor.|
[0B] . 63 6F 6D 2F |com/|
[0C] . 4D 6F 75 6E |Moun|
[0D] . 74 61 69 6E |tain|
[0E] . 46 4D FE 00 |FM..|
[0F] . 00 00 00 00 |....|

Read with NFC Tag Info Android application from NXP
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Project Status & Next Steps

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Current Status of the Project
I have built a working and stable prototype
It plays32kbps streams from internet
It works with NDEF formatted Mifare Ultralight tags (type 2)
I use Android application to write the content of the tags
For other tag types or unformatted type 2 tags, the device
plays hardcoded internet radio stations defined in the code
Arduino script size is around 34kB (including all the libraries)

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Next Steps?
Clean up all the code and publish it in github
Replace the Ethernet shield by the new ArduinoWiFi shield
and try to play streams with higher bitrates
Integrate AM/FM Radio shield
Improve the NFC library to support other types of NFC Tags
Implement Card Emulation and/or Peer-to-Peer mode in
NFC library to interact directly with an Android application
over NFC
Port the solution to an Android USB dongle (can be bought
now for less than €50)

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More Info

Javier Montaner (Madrid, Spain)
montanerj@yahoo.com
@tumaku_ (twitter)

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