The document describes designing an Internet of Things (IoT) jukebox system using the Brillo operating system that allows customers to control music playback in bars. The system uses an Intel Edison board running Brillo connected to speakers and a light sensor. It implements a Weave service that exposes music playback state and allows remote control via commands. Playback and downloading are handled by a jukebox service while volume is controlled based on ambient light levels using a separate volume service.

1. Designing the IoT “Jukebox”
with Brillo
Constantin Musca
Software Engineer at Intel

2. Outline
• Problem statement
• Solution
• System Architecture
• Implementation
• Conclusions and future work
• Demo

3. Problem statement
• Random music in bars
• Music cannot be controlled
• Lack of customer engagement

4. Mission
Music is personal.
Let’s eliminate random music.

5. Solution: Brillo
What is Brillo ?
• Embedded OS
• Core services
• Developer kit
Image Source: Google

6. The Brillo Operating System
• Open Source
• Maintained
• Supports devices as small as 128MB
of storage and 32MB of RAM
• Customizable Hardware
Linux Kernel
Android HAL
Device
Admin
System
Services
OTA
updates
…Connectivity

7. The Brillo Core Services and the Developer Console
• Weave
• Metrics
• Crash reporting
• OTAs
Image Source: Google

8. The Brillo Developer kit
• Based on the Android.mk architecture
• Standard testing
• Android debug bridge (adb)
Image Source: Google

9. Weave
Image Source: Google
• Protocol for device discovery, provisioning,
authentication, and interaction
• Schema Driven (JSON)
• OAuth 2.0 Authentication, Google as AS

10. Intel Edison Arduino Board
• High performance dual core Intel CPU
• Wi-Fi antenna within the Edison Chip
• Support for USB, GPIOs, I2C, SPI
Image Source: intel.com

11. Grove Starter Kit & USB Speakers
• Grove Base Shield
• Grove Light Sensor
• Grove LCD
• USB Speakers

12. Hardware System Connections

13. Software System Architecture
JBClient
USB Audio HAL
JBService
Grove LCD supportWeave support
Binder
Weave Enabled
Applications
Weave Developer Console
Android Application
Weave
Brillo OS JBVolumeService

14. Implementation: JBClient
• Connects to JBService through Binder
• Acts as middleman for all Weave - JBService
communication
• Maintains and updates the Weave device state
Image Source: developers.google.com/weave

15. Implementation: Jukebox Weave Commands Schema
"commands": {
"play": {
"parameters": {
"songName": {
"type": "string",
"minLength": 5
}
}
},
"pause": {},
"resume": {},
"stop": {},
"download": {
"parameters": {
"trackUrl": {
"type": "string",
"minLength": 5
},
"filename": {
"type": "string",
"minLength": 5
}
}
}
} Image Source: developers.google.com/weave

16. Implementation: Jukebox Weave State Schema
"state": {
"status": {
"type": "string",
"enum": ["idle", "playing", "paused"]
},
"songs": {
"type": "array",
"items": {"type": "string"}
},
"downloadStatus": {
"type": "string",
"enum": ["idle", "downloading"]
}
}
Image Source: developers.google.com/weave

17. Implementation: Exposed Weave States
Weave states:
• Playing status - [idle, playing, paused]
• Downloading status - [idle, downloading]
• Playlist - list of strings
Playing
Idle
Paused Idle Downloading

18. Implementation: Jukebox Service
JBService
• Ensures a healthy and stable music playing life cycle
• Uses Stagefright exposed AudioPlayer for handling music
• Uses CURL for downloading new songs
• Exposes a list of supported songs (playlist) to Jukebox Client

19. Implementation: Jukebox Service details
play(song)
pause()
resume()
stop()
Jukebox Player
displayVolume(volume)
displaySong(song)
displayStatus(status)
LCDServiceProxy
downloadSong(url, filename)
getPlaylist()
PlaylistManager
play(song)
pause()
resume()
stop()
download(url, filename)
getPlaylist()
JBService

20. Implementation: AIDL Interface
interface IJBService {
boolean is_playing();
void play(String song_name);
void pause();
void resume();
void stop();
void download(String track_url,
String filename);
boolean is_downloading();
String get_playlist();
}

21. Implementation: Jukebox Volume Service
JB Volume Service
• Maps the range of supported values from Light Sensor to
volume
• Updates the system volume based on the ambient lighting
• Less light yields lower volume while more bright rooms yield
higher volume

22. Implementation: Jukebox Volume Service
Linux Kernel
libmraa
libupm
Brillo Sensors HAL
Jukebox Volume Service
Sensors HAL API
• get_sensors_list(list)
• activate(sensor, true/false)
• batch(sensor, flags, sampling period, maximum report latency)
• setDelay(sensor, sampling period)
• flush(sensor)
• poll()
libupm
• https://github.com/intel-iot-devkit/upm
libmraa
• https://github.com/intel-iot-devkit/mraa

23. Conclusions and future work
Conclusions
• It’s easy to build a Weave controllable
Jukebox using Brillo
Future work:
• Add support for multiple playlists
• Increase the context awareness

24. Demo

26. Legal Notices and Disclaimers
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•© 2016 Intel Corporation.