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TinyOS Course 00: Introduction to WSN
- 1. WSN Programming Course Introductionto Wireless Sensor Networks Manuel Fernández UAH, 18th September 2013
- 2. Contents •What areWireless SensorNetworks? •WSN Advantages & Challenges •Applications • Future ofWSN •What are Motes? •WSN Evolution • IEEE 802.15.4 • IEEE 802.15.4 vs. ZigBee • Future of IEEE 802.15.4 • Embedded Operating Systems • Introduction toTinyOS 2.x 2
- 3. • A WirelessSensor Network (WSN) is a wireless network of small autonomous devices spatially distributed over a certain area that cooperatively monitor physical or environmental variables through their attached sensors, and transmit this information to a main location. What are WSNs? 3
- 4. • Advantages: • Lowcost devices • Low power • Easy and quick to deploy • Scalability (increase network robustness) • Challenges: • Energy constrained • Limited memory and computation • Low Bandwidth WSN Advantages &Challenges 4
- 5. • Monitoring ofobjects • Monitoring of areas • Monitoring of objects and areas Applications 5
- 6. Monitoring of objects •Structural Monitoring • Condition-based Maintenance • Medical Diagnostics • Urban terrain mapping Example:Condition-based Maintenance Fabrication plants: • Sensors collect vibration data, monitor wear and tear; report data in real-time • Reduces need for a team of engineers; cutting costs by several orders of magnitude Applications 6
- 7. Monitoring of areas •Environmental and Habitat Monitoring • PrecisionAgriculture • Indoor Climate Control • Military Surveillance •TreatyVerification • IntelligentAlarms Example: Precision agriculture • Precision agriculture aims at making agricultural operations more efficient and cost effective, while reducing environmental impact. • The information collected from sensors is used to evaluate optimum sowing density, estimate fertilizers and other inputs needs, and to more accurately predict crop yields. Applications 7
- 8. Monitoring of objectsand areas •Wildlife Habitats • Disaster Management • Emergency Response • Ubiquitous Computing •AssetTracking • Health Care • Manufacturing Process Flows • … Applications 8
- 9. Smart Home/Smart Office •Sensors controlling appliances and electrical devices in the house • Better lighting and heating in office buildings. Biomedical/Medical • Health Monitors:Glucose /Heart rate • Chronic disease: artificial retina/ cochlear implants • Hospital sensors: monitor vital signs/ record anomalies Traffic management & monitoring •Traffic flow • Real time routing update Industrial & Commercial •Agricultural crop conditions •Inventory tracking •Plant equipment maintenance monitoring •Automated problem monitoring Future of WSN 9
- 10. • Low costand power computer • Sensors • Radio module • Storage • Power unit What are Motes? CONTROL SENSOR 3 10
- 11. • CM5000 What areMotes? 11
- 12. WSN Evolution • Firstdevelopments for military applications • At the end of the 90’s, the possibilities of this technology were very evident for researches & the industry across the globe. • In 2003 the IEEE 802.15.4 standard was formulated. The first embedded operating systems are developed • First WSN designs are distributed systems • Newest designs focus on in-node processing and actuation, and multipoint communication 12
- 13. • In 2003the IEEE 802.15.4 standard was formulated, as an answer to the industry needs for a common communication stack among small devices • This stack is aimed towards low power consumption, and low data transfer rates • The communication stack focuses on the definition of the frequencies of operation, and how they physically access the medium IEEE 802.15.4 13
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- 15. 802.15.4 802.11 (Wi-Fi) Bluetooth UWB (Ultra Wide Band) WirelessUSB IR Wireless Data Rate 20, 40, and 250 Kbits/s 11 & 54 Mbits/sec 1 Mbits/s 100-500 Mbits/s 62.5 Kbits/s 20-40 Kbits/s 115 Kbits/s 4 & 16 Mbits/s Range 10-800 meters 50-100 meters 10 meters <10 meters 10 meters <10 meters (line of sight) Networking Topology Ad-hoc, peer to peer, star, or mesh Point to hub Ad-hoc, very small networks Point to point Point to point Point to point Operating Frequency 868 MHz (Europe) 900-928 MHz (NA), 2.4 GHz (worldwide) 2.4 and 5 GHz 2.4 GHz 3.1-10.6 GHz 2.4 GHz 800-900 nm Complexity (Device and application impact) Low High High Medium Low Low Power Consumption (Battery option and life) Very low (low power is a design goal) High Medium Low Low Low IEEE 802.15.4 Tech comparison: 15
- 16. IEEE 802.15.4 vs.ZigBee IEEE 802.15.4 IS NOTTHE SAME AS ZIGBEE!!! 16
- 17. • IPv6 over802.15.4 • 6LoWPAN • Blip • RPL (IETF ) • …. • Industrial Automation with IEEE 802.15.4 • WirelessHART • ISA100 • … Future of IEEE 802.15.4 17
- 18. • Embedded OSrun inside the mote and take care of most of most of the operations, always focusing on achieving a low power state • This allows the programmer to focus on developing applications, and staying away from low power tinkering • Among the most popular, TinyOS and Contiki lead the research Embedded Operating Systems 18
- 19. Introduction to TinyOS-2.x 19 Overview •Oneof the first OSs to target WSNs – currently the most widespread • Emphasis is on memory consumption – both program and data memory • Open-source w/ rich component library • Memory efficient • Rich tool-chain • Large code-base and user community
- 20. TinyOS Features: •TinyOS isprogrammed in nesC • nesC is a C-style language • nesC provides the programming abstractions – component based • Split-phase execution – return values arrive asynchronously through events • Tasks provide the unit of concurrency – typically spawned by events – can be pre-empted by asynchronous events – FIFO scheduling • Pre-emptive threaded model with TOSThreads Introduction to TinyOS-2.x 20
- 21. • TinyOS abstractseverything as a component: – Components can be reused – Components can be replaced – Components can be hardware or software 21 Introduction to TinyOS-2.x
- 22. Component-oriented Programming • Object-OrientedProgramming: – Focuses on the relationships between classes that are combined into one large binary executable • Component-Oriented Programming: – Focuses on interchangeable code modules that work independently and don't require you to be familiar with their inner workings to use them. 22 Introduction to TinyOS-2.x
- 23. TinyOS Architecture Sensing CommsOther Libraries Application Main (scheduler) Hardware Abstractions (ADC, CLOCK, I2C, LEDS, PHOTO, UART, SPI) 23 Introduction to TinyOS-2.x
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