computer engineering and networks laboratory btnodes applications and architecture compared jan...
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Computer EngineeringComputer Engineeringand Networks and Networks LaboratoryLaboratory
BTnodes
Applications and Architecture Compared
Jan Beutel, Oliver Kasten, Matthias Ringwald
Juli 10, 2003
Slide 2
BTnodes - Jan Beutel and Oliver Kasten
Initial Projects
Smart everyday objectsby attaching sensor nodes:– self aware– context sensitive– cooperative– integration into computing environment
Ad hoc networking scenarios– integrated application protocols– scalable multi-hop routing
Wearable Computing
Juli 10, 2003
Slide 3
BTnodes - Jan Beutel and Oliver Kasten
Consumer Electronics Integration
PDA
BTnodePC
Peripherals
BTnode
Mobile Phone
Camera
Juli 10, 2003
Slide 4
BTnodes - Jan Beutel and Oliver Kasten
Backend Connectivity
Connectivity to– application servers– other networks
Clusters of mobile networks– using GSM– using SMS services– Wireless LAN– interfacing to other
sensor networks
BTnodes
Bluetooth Gateway
Internet
LocalApplication
Juli 10, 2003
Slide 5
BTnodes - Jan Beutel and Oliver Kasten
Bluetooth Piconets
S1’’ S2’’
S3’’M’’
S1 S2
S3M
S2'
S1'
M'
Communication organized in piconets– controlled by one master– up to 7 active slaves– 255 inactive (parked) slaves
Master-Slave– implements centralized control– synchronization of all slaves– only master-slave communication
Multiple piconets– separate channels– no coordination
Juli 10, 2003
Slide 6
BTnodes - Jan Beutel and Oliver Kasten
Bluetooth Host Controller Interface
– standard interface for protocol software – providing access to lower levels of the protocol stack
HCI_COMMANDHCI_EVENT
Bluetooth module
Host processor
Physical interfaceHost Controller Interface
RF
Baseband
Audio Link Manager
L2CAP
SDP
Applications
RFCOMM ...
UART
OGF OCF PARAMETERS
Juli 10, 2003
Slide 7
BTnodes - Jan Beutel and Oliver Kasten
Bluetooth Connections
Managed by the host controller
Statemachine for each connection
Link Layer Control & Adaptation (L2CAP)– connection-oriented– connectionless data– protocol multiplexing for a
single “air interface”– packet segmentation and reassembly– channel abstraction– encryption– security– …
RF
Baseband
Audio Link Manager
RFCOMM
Host Controller Interface
SDP ...
Applications
L2CAP
Connected
Disconnected
Req DiscReq Conn
Juli 10, 2003
Slide 8
BTnodes - Jan Beutel and Oliver Kasten
Hardware Requirements
Autonomous wireless communication and computing platform based on a Bluetooth radio module and a
microcontroller.
Requirements– small form factor, low component count– standardized wireless interface– flexible and cost effective deployment of large quantities of
networking nodes
Juli 10, 2003
Slide 9
BTnodes - Jan Beutel and Oliver Kasten
61 mm
40
mm
Hardware Details
IntegratedPIFA Antenna
LEDs,Reset,Clocks
CommunicationEricsson Bluetooth Module
Generic Sensor Interfaces
UART and I2C Data Interfaces
Power Management
Memory128 kB Flash244 kB SRAM4 kB EEPROM
CPUAtmel ATmega 128L MCU8-Bit RISC (max. 8 MHz ~8MIPS)
Juli 10, 2003
Slide 10
BTnodes - Jan Beutel and Oliver Kasten
Designing for Power Aware Operation
Features– optional switchable power supply for Bluetooth module– MCU with 6 power down modes, low idle/sleep current– frequency scaling: 7.3 MHz - 57 kHz
– single power supply (3.6 – 16 V), single internal voltage (3.3 V) – battery charge indicator– direct current access shunts for all components– internal Vcc available at every connector to power external
sensor modules
Power consumption @ 7.3 MHz [mW] max typ Lifetime [h]*– Bluetooth Connected/CPU On 250 160 12-19– Bluetooth Idle/CPU On 95 67 32-45– Bluetooth Off/CPU Idle 15 12 202-252– Bluetooth Off/CPU Sleep 6 <0.5 504-6048
*on 840 mAh Li-ion
Juli 10, 2003
Slide 11
BTnodes - Jan Beutel and Oliver Kasten
Power Consumption Details
SensingTX/RX
Idle SensingTX/RX
Sensor Network Example: 10% duty cycle
Operation Power consumption [mW] Lifetime [h]*
4 sec sensing 12 2522 sec communication 160 1954 sec idle 0.5 6048
Total duty cycle ~ 6.5 mW 421*on 840 mAh Li-ion
t
P
Juli 10, 2003
Slide 12
BTnodes - Jan Beutel and Oliver Kasten
Lightweight OS– event-driven application model
– cooperative multithreading
– device drivers (UART, RTC, ADC, ...)
Programming– standard C language
– high-level Bluetooth interface
– system software available as library
– emulation environment on Linux
System Software
Juli 10, 2003
Slide 13
BTnodes - Jan Beutel and Oliver Kasten
Multiple Drivers and the Dispatcher
received_irq()
Hardware
void handler( /* ... */ ) {}void main() { btn_disp_ev_reg( RECEIVE_EV, handler, 0 ); btn_disp_run();}
Application
Driver
handler()
read buffer
event buffer
Dispatcher
EVENT, handler funcRECEIVE_EV, handler()OTHER_EV, func2()
btn_disp_run()
RECEIVE_EV
handler()
read()
Juli 10, 2003
Slide 14
BTnodes - Jan Beutel and Oliver Kasten
#7#2
#4
#292
80
9 m
3 2 45 1
No Airpoc
ket
Better Avalanche Rescue through Sensors
orientation, mobility
air pocket detection
heart rate, oxygen saturation
oxygen sensor
accelerometer, inclination
oximeter
Juli 10, 2003
Slide 15
BTnodes - Jan Beutel and Oliver Kasten
Bluetooth enabled Appliances
Communication with other Bluetooth enables devices – standard Bluetooth profiles for SMS, object push and
RFCOMM
BTnode enabled Egg Carton SMS from Egg Carton Interactive Dialog
Juli 10, 2003
Slide 16
BTnodes - Jan Beutel and Oliver Kasten
XHOP/R-DSR Multihop Network
Bluetooth multihop source routing prototype
– integrated scalable application protocol
– based on Dynamic Source Routing (CMU)
– routing across piconet borders to support >8 nodes
Remote topology discovery– script like command
language in the payload
Performance– 1-2 sec per hop,
depending on inquiries
Juli 10, 2003
Slide 17
BTnodes - Jan Beutel and Oliver Kasten
Other Projects using BTnodes
200 units with 16 research groups– smart objects– routing– wearable computing– perceptual computing– operating systems
VTT, FI DSG, ETH Zurich, CH
PCCV, ETH Zurich, CHTecO, University of Karlsruhe, GE
PLAY, Interactive Institute, SE TIK, ETH Zurich, CH
IFE Wearable Lab, ETH Zurich, CHNTT DoCoMo, Munich, GE
Ptolemy Group, UC Berkeley, USAArt of Technology, Zurich, CH
DistLab, Diku, Copenhagen, DKLAP, EPF Lausanne, CH
CS Department, Lancaster University, UKLSL, EPF Lausanne, CH
TinyOS Group, UC Berkeley, USAUniversity of Uppsala, SE
Bill of material 50 parts
Parts 60 USDAssembly 5 USDBluetooth 45 USD
Unit cost @ 200 units 110 USD
Juli 10, 2003
Slide 18
BTnodes - Jan Beutel and Oliver Kasten
Hands-on experience
From tool installation to first application in less than a day
20 student projects completed
Bootcamp held
twice for related
research projects