1. Computer Engineering and Networks Laboratory BTnodes - Jan Beutel and Oliver Kasten BTnodes A Distributed Platform for Sensor Nodes Hard- and Software Architecture

2. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 2 Projects Smart everyday objects –by attaching sensor nodes: –self aware –context sensitive –cooperative –integration into computing environment Ad hoc networking scenarios –integrated application protocols –scalable multi-hop routing

3. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 3 A device magnitudes smaller than a PDA … equally flexible and programmable … … and supporting Bluetooth. Architecture Considerations SensingCommunicationComputation

4. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 4 BTnode

5. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 5 Consumer Electronics Integration PDA BTnode PC Peripherals BTnode Mobile Phone Camera

6. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 6 Backend Connectivity i  Connectivity to –application servers –other networks BTnodes Bluetooth Gateway Internet Local Application

7. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 7 Backend Connectivity ii AT commands –GSM dial in –SMS send/ receive –GSM cell information BTnode GSM phone GSM GSM Infrastructure PSTN Modem pool Dial-in server Internet

8. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 8 61 mm 40 mm Hardware Details Integrated PIFA Antenna LEDs, Reset, Clocks Communication Ericsson Bluetooth Module Generic Sensor Interfaces UART and I2C Data Interfaces Power Management Memory 128 kB Flash 64 kB SRAM 4 kB EEPROM CPU Atmel ATmega 128L MCU 8-Bit RISC (max. 8 MHz ~8MIPS)

9. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 9 Power Consumption Sensing TX/RX Idle Sensing TX/RX Sensor Network Example: 10% duty cycle OperationPower consumption [mW]Lifetime [h]* 4 sec sensing12 252 2 sec communication16019 54 sec idle 0.56048 Total duty cycle~ 6.5 mW421 *on 840 mAh Li-ion t P

10. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 10 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

11. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 11 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

12. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 12 Over-the-air Software Updates Bootloader support of the MCU –new firmware in XHOP payload –Flash reprogramming from pre- cached data –reprogramming of single node and by network flooding Per-hop performance –transmitting 10 kB: ~0.8 sec –writing to Flash: ~0.2 sec Overall performance –~10s to transmit, write and reboot with 80 kB firmware

13. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 13 Projects using BTnodes 200 units with 13 research groups –smart objects –routing –wearable computing –perceptual computing –operating systems VTT, FI DSG, ETH Zurich, CH PCCV, ETH Zurich,CH TecO, University of Karlsruhe, GE PLAY, Interactive Institute, SE TIK, ETH Zurich, CH IFE Wearable Lab, ETH Zurich,CH NTTDoCoMo, Munich, GE Ptolemy Group, UC Berkeley, USA Art of Technology, Zurich, CH DistLab, Diku, Copenhagen, DK LAP, EPF Lausanne, CH CS Department, Lancaster University, UK Bill of material50 parts Parts90 CHF Assembly15 CHF Bluetooth 65 CHF Unit cost @ 200 units170 CHF

14. BTnodes - Jan Beutel and Oliver Kasten February 13, 2003 Slide 14 Hands-on experience  From tool installation to first application in less than a day  20 student projects completed Hackfest held for the second time tomorrow