Ravi Jain 12/2/03 1 CodeBLUE : A Bluetooth Interactive Dance Club System Dennis Hromin, Michael...
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Transcript of Ravi Jain 12/2/03 1 CodeBLUE : A Bluetooth Interactive Dance Club System Dennis Hromin, Michael...
Ravi Jain 12/2/03 1
CodeBLUE: A Bluetooth Interactive Dance Club System
Dennis Hromin, Michael Chladil, Natalie Vanatta, David Naumann,
Susanne Wetzel
Dept of Computer Science,
Stevens Inst of Technology
Farooq Anjum, Ravi Jain*
Applied Research,
Telcordia Technologies
*Current affiliation: DoCoMo USA Labs
Ravi Jain 12/2/03 2
Outline
• Motivation and Background
• System design
• Implementation
• Lessons learned
• Conclusions
Ravi Jain 12/2/03 3
Motivation
• Collaborative music creation– One of the most powerful forms of human
communication
• Can Bluetooth be used to enable music collaboration for untrained participants?– What are the strengths and limitations of
Bluetooth for such an application?
Ravi Jain 12/2/03 4
Approach
• Allow participants to transform simple dance movements into musical modifications
• Why Bluetooth?– Low cost
– Unlicensed ISM band
– Low power
– Small size
– Cool name …
Ravi Jain 12/2/03 5
Requirements
• Unobtrusive– Small size, low weight, easily wearable– About the size of a club wristband
• Rugged– Mosh pits
• Long battery life to minimize maintenance• Very low cost
– Ideally pennies, but dollars may be acceptable
• Responsive
Ravi Jain 12/2/03 6
System design
Sensor
Access Point
Single-board Computer
codeBLUE DJPC
Club Sound SystemClub Light System
MIDI Converter
Light Synthesizer Music Synthesizer
OriginalMusic Modified Music
Slave
Master
Ravi Jain 12/2/03 7
Outline
• Motivation and Background
• System design
• Implementation
• Lessons learned
• Conclusions
Ravi Jain 12/2/03 8
CodeBLUE SensorsSensor Parameter Method Range Size (mm)
G-force Single-axis Acceleration
Piezo-electric
+/- 2.5 G 56x38x19
Close Proximity IR reflection
80 cm 13x40x30
Bend Flex angle Piezo-resistive
0-130o 110x7x0.5
Touch-Mini
Contact Pressure
Force-sensitive resistor
100g-10Kg
19 (circle) x0.5
Hot Temp Zener -14-100o C 6x10x8
Light Ambient light
Photo-resistor
130o
acceptance
6x10x5
Ravi Jain 12/2/03 9
Wireless sensor module
Body Sensor
PIC Microcontroller
UART Interface
Baseband Controller
RF Transceiver
Bluetooth Module
Up to 5 sensors are supported
364 bytes RAM, 8 kB ROM
Bluetooth 1 Mbps ACL data link
Ravi Jain 12/2/03 10
Protocol stack
• For the wireless link, L2CAP only is used• Higher layers of Bluetooth & IP not used to save memory & time
• Data sent to AP consists of sensor ID plus 7-bit digitized sensor value
Baseband / RF
LMP
HCI
L2CAP
Presentation Layer
Sensor Data Acquisition Application
Ethernet
IP
UDP
Presentation Layer
MIDI Applications
Baseband / RF Ethernet
IP
UDP
LMP
HCI
L2CAP
Bluetooth-to-IP Conversion Layer
Ravi Jain 12/2/03 11
DJ Console and Controller
• Data Filter algorithms must keep output within acceptable ranges• Must be smooth yet obvious to participants• Must be flexible enough to give the DJ creative room• Must be accessible via a simple, intuitive GUI• Fertile area for future research!
Configurator
Data Filter MIDI Player
MIDI Song Files
Sensor data
Ravi Jain 12/2/03 12
MIDI
• What is Musical Instrument Digital Interface (MIDI)?– binary data files containing instructions that tell
electronic instruments how to play a song– much like musical scores
• Why MIDI?– Much more efficient representation
• PCM: 10 MB/minute of stereo audio sampled at 44.1 kHz• MIDI: 10 kB/minute
– Can easily modify instructions in real time
Ravi Jain 12/2/03 13
Outline
• Motivation and Background
• System design
• Implementation
• Lessons learned
• Conclusions
Ravi Jain 12/2/03 14
Related work• The Brain Opera, Machover 1996, 2000
– Not wireless
• The Interactive Dance Club, Synesthesia 1998– Not wireless
• Cybershoe, Paradiso 1998– Similar but limited to shoe, possible scalability issues, higher cost
• CosTune, Nishimoto 2001– Not a collaboration on a single song
• Music in Motion, Ng 2000, 2001– Interprets movement captured by a video camera
• Web of Life, Center for Art and Media, Karlsruhe, permanent display– Most similar, video images change in response to users hand movements
Ravi Jain 12/2/03 15
Discussion
• System Cost– Sensor module:
• $500 for Bluetooth (Yr 2000), $100 for the rest• Expected cost in volume is ~$5
– Access point• About $1000 as implemented (with Linux single-board PC)• Can be easily reduced to ~$100
– DJ Console and converter• Standard PC with MIDI player: ~$1000
– Sound and light hardware• MIDI converter (MidiMan), Dance Synth (E’Mu Mo’Phatt), Audio
Mixer (Mackie), Lighting Controller (DMX)• ~$4000
Ravi Jain 12/2/03 16
Discussion
• Total Effort: 24 staff-months• Usability
– Sensor module• 7 cm x 5 cm x 3 cm (without the sensor itself) • About 100 g• Size can be reduced (at least) 4x by one-chip
Bluetooth module and Li-Ion polymer battery
– DJ GUI– Data Filter algorithms
Ravi Jain 12/2/03 17
Wireless technology• codeBLUE requirements
– differ slightly from those generally considered in the literature• Voice, video, web browsing, m-commerce transactions• Needs very low bandwidth (~2 kbps) but also low latency (< 100 ms)
– Low-cost, small client size, low-power, rugged– Low maintenance cost and complexity
• Bluetooth is adequate– Designed as a cable replacement– Low bandwidth, small size, low latency– Reasonable spectral efficiency– Easy serial interface
Ravi Jain 12/2/03 18
Bluetooth Issues for codeBLUE
• User module cost still too high• Installation requires cabling to AP
– Expensive, cumbersome, unsightly, too fixed
– Power to AP could be avoided by batteries but currently consumption is too high
– Using wireless backhaul is problematic• Bluetooth scatternet requires complex scheduling and may not
meet time constraints
• 802.11b backhaul raises cost and interference issues
Ravi Jain 12/2/03 19
Other Bluetooth Issues
• Spatial Capacity– Max of seven active slaves per master (~10m – 30m
radius)
– Can put slaves into PARK, HOLD etc but this is complex
• The protocol stack is needlessly complex (for this application, at least)– Would prefer native IP running on a simple link layer
• Security
Ravi Jain 12/2/03 20
What about good old 802.11b instead?
• Cost still an issue• Power consumption is worse
– 180-450 mA versus ~70 mA
• Low spectral efficiency for small data packets• Hard to get delay guarantees (especially if shared)• Larger real-estate requirements, with large parallel
bus• Cabling issues still arise
Ravi Jain 12/2/03 21
Bluetooth vs 802.11b for codeBLUE
Attribute Bluetooth 802.11b
User module cost Slightly high Too high
Power OK Too high
Spectral efficiency OK Low
Delay OK OK, but not if shared
Spatial capacity Low OK
Cabling Problematic Problematic
Protocol Complex Simple
Security Not clear Not clear
Ravi Jain 12/2/03 22
Conclusions• codeBLUE was demonstrated twice to a live audience
– Stevens Inst of Technology annual Technogenesis Award, 2001
• Sensor technology is more than adequate• Bluetooth technology is adequate
– Better than 802.11b– but not ideal
• Ideal: – low-cost, low-power, multi-hop wireless telemetry network with – simple, efficient, IP-based, secure protocols and– rugged, disposable sensor clients
Ravi Jain 12/2/03 23
Further work• Needed
– A protocol stack that provides IP, and • marries the simplicity of 802.11b with
• the low power, size and spectral efficiency of Bluetooth
– A low-cost, rugged wireless sensor module for human-scale measurements
– Simple, configurable wireless security
Ravi Jain 12/2/03 24
Work in Progress
• In progress: case study for research in Bluetooth security – DJ PC application rewritten in Java to allow real-time
plug-in of 3rd party software to allow the DJ more choices
– But plug-ins open security risks– Rely on Java and .NET code access security
mechanism for runtime checks– But are these necessary and sufficient?– Use static analysis [Banerjee02,Banerjee02a]