1. Computer Engineering and Networks Laboratory BTnodes Prototyping Wireless Sensor Network Applications with BTnodes Jan Beutel Siemens Workshop 2004

2. 2 Prototyping Wireless Sensor Network applications on real devices in a heterogeneous environment BTnode – Ad hoc networking prototyping platform Event driven OS/application integration Example application Overview

3. 3 Prototyping Wireless Sensor Networks A myriad of interacting devices –sensor node heterogeneity –sensing and actuation –user interaction Smart everyday objects by attaching sensor nodes: –self aware –context sensitive –cooperative –integration into computing environment NCCR-MICS Terminodes

4. 4 Backend connectivity Infrastructure integration Local applications Mobile network gateways –GSM –SMS –Wireless LAN –interfacing to other sensor networks Debugging and monitoring –development –quantitative analysis BTnodes Bluetooth Gateway Internet Local Application

5. 5 A look at platform competitors UC Berkeley motes – Crossbow, MoteIV (Culler) –Motes and IPAQ’s (Estrin) –Mote-on-a-chip “spec” – MoteInc (Hill) Bluetooth devices –Imotes – Intel Research (Kling) –Blue Wand – Beecon (Zitterbart) Testbeds –Microsoft wake-on wireless (Bahl) –UCLA i-Badge (Srivastava) –UCLA/WINS/Rockwell nodes (Srivastava) –PicoRadio Testbed (Rabaey) Other –TeCo Smart It’s (Beigl) –PicoBeacon (Rabaey) –WiseNet (Enz) –ParkTab (Weiser) –Active Bat (Hopper et al.) full custom radio proprietary limited availability complex and low integration low power reduced features full custom

6. 6 Lightweight wireless communication and computing platform based on a Bluetooth radio module and a microcontroller. Bluetooth has the advantage of –availability today for experimentation –compatibility to interface to consumer appliances –an abstract, standardized high level digital interface BTnode architecture

7. 7 BTnode hardware details Integrated hardware features –8-Bit RISC, max. 8 MIPS –128 kB Flash –64 kB SRAM, 180 kB data cache –operating from 3 cell batteries –integrated antenna –power management –generic sensor I/O 61 mm 40 mm Current bill of material50 parts Parts60 USD Assembly5 USD Bluetooth 45 USD Unit cost @ 200 units110 USD

8. 8 Lightweight OS –event-driven application model –cooperative multithreading –device drivers ( UART, RTC, ADC,... ) –static memory allocation –minimum memory footprint Programming –standard C language –high-level Bluetooth interface –system software available as library –emulation environment on Linux BTnode System Software

9. 9 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

10. 10 Other BTnode applications Many successful BTnode applications –The Lighthouse location system [Roemer2003] –Smart product monitoring [Siegemund2002] –Bluetooth enabled appliances [Siegemund2003] –Smart It’s friends [Siegemund2003] –XHOP/R-DSR multihop prototype [Beutel2002] –Distributed positioning – TERRAIN implementation [Frey2003] –Physical activity detection network [Junker2003] –Better avalanche rescue through sensors [Michahelles2002] –Wearable unit with reconfigurable modules [Plessl2003] –Undergrad projects with Lego Mindstorms [Blum2003] –… Mostly relying on simple point to point data links

11. 11 Constructing large network topologies How to construct an ad hoc network topology with Bluetooth –large network, many devices –all devices connected, supporting transparent multihop transport XHOP prototypeTreeNet topology

12. 12 To probe further… http://www.btnode.ethz.ch

13. 13 BTnode/TreeNet collaborators –Oliver Kasten, Friedemann Mattern, Matthias Ringwald, Kay Römer, Frank Siegemund –Regina Bischoff, Roger Wattenhofer, Aaron Zollinger –Jan Beutel, Matthias Dyer, Lennart Meier, Martin Hinz, Lothar Thiele Related publications J. Beutel et al.: Prototyping Wireless Sensor Networks with BTnodes. EWSN 2004. R. Bischoff and R. Wattenhofer: Analyzing Connectivity-Based Multi-Hop Ad Hoc Positioning, PerCom 2004. J. Beutel, O. Kasten and M. Ringwald: BTnodes - A Distributed Platform for Sensor Nodes. ACM SenSys 2003. M. Leopold et al.: Bluetooth and Sensor Networks – A Reality Check. ACM SenSys 2003. K. Römer: The Lighthouse Location System for Smart Dust. ACM MobiSys 2003. O. Kasten, M. Langheinrich: First Experiences with Bluetooth in the Smart-Its Distributed Sensor Network. PACT 2001. Acknowledgements