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European Workshop ICT and Civil Protection: current state and future scenarios. Senigallia, 18-19 June 2007. Wireless sensors solutions for environmental monitoring applications : why?. Advantages:
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European Workshop ICT and Civil Protection: current state and future scenarios Senigallia, 18-19 June 2007
Wireless sensors solutions for environmental monitoring applications: why? Advantages: • No connection problems due to distance between the sensor and the LWU and obstacles between them • Freedom in the choice of the installation place • Easy to connect (plug and play solution) • Unlimited diffusion of the data (with access key) • Fast and easy to install and to mantain (there is no need of qualified people to do it) ICT and Civil Protection Senigallia, 18-19 June 2007
Wireless sensors solutions for environmental monitoring applications: architecture ICT and Civil Protection Senigallia, 18-19 June 2007
Wireless sensors solutions for environmental monitoring applications: protocols The wireless solution in the field of sensors presents wide sperimental and innovation margin. This solutions can be searched inside various polifunctional standard, that can be classified depending on the working area: • WPAN (Wireless Personal Area Network) • BlueTooth (IEEE 802.15.1) • BlueTooth 2 (IEEE 802.15.3) • ZigBee (IEEE 802.15.4) • sensori smart WPAN (IEEE P1451.5a) • WUSB a basso rate (Wireless Universal Serial Bus su LR-WPAN, IEEE 802.15.4) • WUSB ad alto rate (Wireless Universal Serial Bus su HR-WPAN, IEEE 802.15.3) • Wireless Firewire (IEEE1394, UWB) • WLAN (Wireless Local Area Network, IEEE 802.11) • WiFi (IEEE 802.11b-g) • sensori smart WLAN (IEEE P1451.5b) • WMAN (Wireless Metropolitan Area Network, IEEE 802.16) • sensori smart WMAN (IEEE P1451.5c) • WiMAX (IEEE 802.16) ICT and Civil Protection Senigallia, 18-19 June 2007
Wireless sensors solutions for environmental monitoring applications • The possible solutions, arranged on the previous categories, can be compared referring to the specific requests and the additional parameters; principally: • Number of connecting sensor • Cost • Power / consumption • Safety • Hardiness / EMC • Distance • Performance (error rate) • Compactness • Transmission speed • Inside the large range of possible solutions showed before, the choice must be restricted toward one of this two standards: ZigBee or WUSB; for each of them here are some of the principal characteristics: ICT and Civil Protection Senigallia, 18-19 June 2007
WUSB characteristics • Datarate: 62.5 kbps max; • Star topology; • Spatial coverage from a minimum of 10m to 50m in open space; • Transmitted signal modulation DSSS type (Direct Sequence Spread Spectrum) • Dinamic adressing of the devices; • Transmission affidability; • Low consumption (average current 90µA); • 79 channels in ISM band at 2.4GHz, that through a mulplation technique of the code can be used to reach a maximum of 3871 simultaneous communications; • Duty-cycle 1%; • Low unitary cost of the devices. ICT and Civil Protection Senigallia, 18-19 June 2007
ZigBee/802.15.4:characteristics • Datarate: 250 kbps max, 20 kbps and 40kpbs ; • Star topology or peer to peer topology; • Spatial coverage from a minimum of 10m to 100m in open space; • Transmitted signal modulation DSSS type (Direct Sequence Spread Spectrum) • Dinamic adressing of the devices (till 65536 connected nodes); • Transmission affidability; • Low consumption (average current 40µA); • 16 channels in ISM band at 2.4GHz, 10 channels in ISM band at 915MHz and one channel in the European band at 868MHz; • Duty-cycle < 0.1%; ICT and Civil Protection Senigallia, 18-19 June 2007
Operating systems for wireless sensors • The properties of a wireless sensors network impose the use of an operating system, that considers: • Small hardware dimensions and low energy avaliability • High number of events in the use of sensors network • Low parallelism level of the sensors network • Need to adequate the same kind of software to different hardware devices • Tolerance to damages in sensors network that work in critical environment ICT and Civil Protection Senigallia, 18-19 June 2007
Operating systems for wireless sensors • An operating system for wireless sensors must be characterized from: • Simplicity: it must avoid operations unuseful and hard working for the operating system • Energetic saving: it must turn off the hardware resources when not working • Efficency: it must fastly manage a large quantity of events to avoid losing precious information • Low parallelism: fast access to the hardware and low execution overhead • Modularity: it must grant reusability and maintenance of the software • Failure tolerance: it must support the development of reliable distributed solutions ICT and Civil Protection Senigallia, 18-19 June 2007
TinyOS • Open source operating system for wireless sensor network • Developed by Berkley’s University and by the Intel research center (www.tinyos.net). • TinyOS has been developed with the following objectives: • Reduce energy consumption, computational charge and memory occupation • Support intensive contemporaneous, robust, efficient and modular operations requests • The result is an operating system characterized by: • Reduced kernel that allows the direct access to the hardware • The memory is considered as a unique and linear physical space, allocated at compilation time ICT and Civil Protection Senigallia, 18-19 June 2007
TinyOS • TinyOS is a very small dimensions operaing system • To satisfy the efficency requirement, TinyOS has been implemented following the events model. • In the field of wireless sensors network, the external events based approach allows to use the hardware resources in the most efficient way. • To satisfy the modularity requirement, TinyOS has been implemented using a components model. • Each component present in TinyOS is an independent software unit provided with interfaces. • The TinyOS system and its applications are written in NesC language. ICT and Civil Protection Senigallia, 18-19 June 2007
Wireless intelligent sensors- General characteristics - • Radio link between the sensor and the LWU (local web unit) • Used frequency range: ISM 2,4GHz • The use of this particular range allows to operate freely without the need of licenses or grants dealing with the European Standards EN 300-220-3, EN 3001-489-3 and to the raccomandations CEPT-ERC-REC 70-03 • Software selectable number of useful channels : 12 • Communication protocol from sensors to the Zbee LWU • Transmission rate: 9600bit/s • Number of connectable sensors 20 • Normal polling cicle: 30 minutes (programmable from 15 minutes to 24 hours) ICT and Civil Protection Senigallia, 18-19 June 2007
Wireless intelligent sensors- General characteristics - • Fast polling cycle: 3 minutes • Each sensor clock interlocked with the LWU one • Auto configuration of every sensor inside the LWU network • Distance between the sensor and the LWU: • superior to 300m without obstacles between the terminals • superior to 30m in presence of obstacles that obstruct the visibility • Non rechargeable power batteries • Power and voltage of the batteries: depending on the sensor • Battery life: superior to 6/12 months depending on the sensor ICT and Civil Protection Senigallia, 18-19 June 2007
- Termoigrometer - • Every minute, acquisition of temperature • and relative damp values. • Validation, through apposite algorithm, • of the acquired values. • Maximum and minimum values calculation, • in the record interval. • Temperature range: –30°C +50°C • Temperature values accuracy: 0,3°C • Range: 0% 100% • Accuracy: 3% • 4 batteries size “C” • Absorption during measurement 5mA • Stand-by absorption 100A • Average absorption including radio • module 0,5mA • Working autonomy superior to 12 months ICT and Civil Protection Senigallia, 18-19 June 2007
- Anemometer - • Acquisition of speed values every • 5 seconds. • Validation, through apposite algorithm, • of the acquired values. • Maximum and minimum values calculation, • in the record interval. • Measurement range: 0m/s 50m/s • Measurement accuracy: 0,5m/s • 4 batteries size “C” • Absorption during measurement 4mA • Stand-by absorption 100A • Average absorption including radio • module 0,4mA • Working autonomy superior to 12 months ICT and Civil Protection Senigallia, 18-19 June 2007
- Gonioanemometer - • Acquisition of speed values every • 5 seconds. • Validation, through apposite algorithm, • of the acquired values. • Maximum and minimum values calculation, • in the record interval. • Measurement range: 0° 360° • Measurement accuracy: 2° • 4 batteries size “C” • Absorption during measurement 2mA • Stand-by absorption 100A • Average absorption including radio • module 0,4mA • Working autonomy superior to 12 months ICT and Civil Protection Senigallia, 18-19 June 2007
- Rainfall sensor- • Registration of the single tip and of the tipping • Instant. • Measures compensation algorithm due to the • rain intensity. • Measurement range: 0 a 300mm/h • Measurement accuracy: 3% • 4 batteries size “C” • Working autonomy superior to 12 months ICT and Civil Protection Senigallia, 18-19 June 2007
- Ultrasonic level sensor - • Acquisition of water level every • 2 minutes. • Validation, through apposite algorithm, • of the acquired values. • Maximum and minimum values calculation, • in the record interval. • Measurement range: 1cm • Measurement accuracy: 0,5m 6m • 4 batteries size “D” • Absorption during measurement 50mA • Stand-by absorption 100A • Average absorption including radio • module 2mA • Working autonomy superior to 6 months ICT and Civil Protection Senigallia, 18-19 June 2007
- LWU (local web unit) - • The LWU picks up the data sent via radio from the sensors and through a web server. It sends the data via GPRS or UHF radio module, with a 9600bit/s modem to the center. • The power for Rx/Tx devices and the Web server it is given by a battery and a solar panel. • Composition of the LWU: • Tx/Rx ISM module for the sensors connection • Web server • Radio device for the connection with the • “Access point” • Average absorption of ISM module during the • connection with the sensor: ≤ 50mA ICT and Civil Protection Senigallia, 18-19 June 2007
- LWU - • Average absorption of the radio device during the connection with the “Access Point”: ≤ 800mA • Average absorption of the system: ≤ 65mA • Autonomy without sunstroke: >30gg • The alternative modules to the radio are: • GPRS module • Trasmitter receiver in UHF band with data • speed trasmission 9600bit/s (GP340 data) ICT and Civil Protection Senigallia, 18-19 June 2007