From Sensors to … … Sensor Networks · PerLab Wireless Sensor Networks Giuseppe Anastasi 3 Overview Sensors Passive Sensors Semi-passive Sensors Sensor Nodes Sensor Platforms

From Sensors to …

… Sensor Networks

From Sensors to …

… Sensor Networks

Giuseppe AnastasiHead of Department

Dept. of Information Engineering, University of Pisa

E-mail: [email protected]

Website: www.iet.unipi.it/g.anastasi/

PerLab

Wireless Sensor Networks Giuseppe Anastasi 2

Introduction

This demonstration class is part of my course

(graduate) course on

Networked Embedded Systems

This course is intended to provide the theoretical background and the basic

methodologies for developing networked embedded systems and applications.

It enables students to design and implement applications, based on networked

embedded devices, in several application domains, such as smart cities, smart

mobility, smart buildings, smart energy, etc.

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Overview

Sensors

Passive Sensors

Semi-passive Sensors

Sensor Nodes

Sensor Platforms

Wireless Sensor Networks

Networking Issues

SensorsSensors

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Passive Sensors

RFID

Semi-passive Sensors

Data loggers

Active Sensors

Sensor nodes

iBeacons

Sensors: Classification

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Sensors: Classification

Temperature

Humidity

Light intensity

Infrared (Presence)

Sound (Noise)

Accelerometer

Compass (direction)

Speed

Pressure

Seismic

Chemical Sensors

Optical Sensors

Pollution

CO, CO2 , NO2 , O3, Benzene

PM10, PM2.5, PM1

Smart Meters

Power Consumption

Energy Consumption

Gas Consumption

Water Consumption

…

Passive TagsRFID, QR-codes

Passive TagsRFID, QR-codes

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QR codes

Quick Response (QR) CodeTwo dimensional barcode that stores information in black

and white dots (data pixels or “QR code modules”)

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QR code generation

Many online generators available

e.g., http://goqr.me/

URL (Website)

Text

Vcard

Sms

Phone Call

Geolocation

Event

E-mail

WiFi

http://www.iet.unipi.it/g.anastasi/

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Using RFID

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Application Areas

Supply chain management

Baggage/Animal tagging

Library information systems

Parcel tracking (postal services)

Smart cities

Access control

Ticketing (public transport, parking, etc.)

Parking area management

Augmented reality

...

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Supply Chair Management

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Baggage Tagging

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Animal Tagging

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Smart Cities

Automatic Access/Tolling

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Augmented Reality

Points of interest in the city (touristic point of interest, shops and public

places) can be tagged through RFIDs or QR codes

Information about the tagged point are made available to the user

(tourist, citizen, …)

Smart Cities

Active TagsBeacons

Active TagsBeacons

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Introduction

iBeacon is a technology originally developed by

Apple

iBeacon-compatible hardware transmitters - typically called

Beacons - available also for non-Apple devices

Enables devices to perform actions when in close

proximity to a Beacon

Beacons emit periodic signals

Mobile devices understand their location

based on the received signal

and perform a specific action

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iBeacon uses Bluetooth Low Energy (BLE) to transmit

Advertisement (ADV) messages

The ADV message is received by a smartphone and forwarded

to a server (e.g., on the cloud)

The server localizes the device (user) and sends appropriate

information to the smartphone

Basic Idea

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How BLE works

BLE communication mainly consists in

Advertisement (ADV) messages

small data packets broadcast at a regular interval by

enabled devices via radio waves

one-way communication

Typical parameter values for iBeacons

Broadcast interval of 100 ms

Broadcast range of up to 100 meters

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Beacon Advertisement Message

UUID (Universal Unique IDentifier) 16 byte string used to differentiate a large group of related Beacons

In its canonical form, a UUID is represented by 32 lowercase hexadecimal digits,

displayed in five groups separated by hyphens, in the form 8-4-4-4-12 for a total

of 36 characters

E.g., ebefd083-70a2-47c8-9837-e7b5634df524

Major 2-byte string distinguishing a subset of Beacons within the larger group

Minor 2-byte string used to identify individual Beacons

Tx Power Used to determine proximity (distance) from the beacon

TX power is defined as the strength of the signal at exactly 1 meter from the device.

This has to be calibrated and hardcoded in advance. Devices can then use this as a baseline to

give a rough distance estimate.

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Application for locating people within the

University of Pisa

UUID (Universal Unique IDentifier) Allows to recognize that ADV messages are emitted from

Beacons belonging to the University of Pisa

Major Identifies ADV messages emitted from Beacons inside a specific

building belonging to the University of Pisa (e.g., Building F)

Minor Identifies a specific room in that Building (e.g., Room F02)

Example

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Application Areas

Localization in Buildings

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Retails: coupons delivered via Beacons to customer

phone (e.g., special offers)

Application Areas

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Tracking: locate museum artworks, shop products,

or cargo containers

Application Areas

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Indoor Navigation: path discover inside a building

and user localization

Applications Areas

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Smart Tagging: allows to give more information

about artworks (also in many languages)

Application Areas

Semi-Passive SensorsSemi-Passive Sensors

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Semi Passive Sensors

Also called data loggers

Powered by a battery

Measures and stores physical quantities

Temperature

Humidity

Shock

…

Can be attached to goods to track their history

Low-cost solution

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System Architecture

Semi-passive Tag

Reader

Server

Data manager

Tag management

Data retrieval and archival

Data visualization

Table, plots

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Application Areas

Ice cream, Frozen Products Distribution

Temperature monitoring

Wine Transport

Temperature monitoring

Shock tracking

Blood Bags Transport

Bag Identification

Temperature tracking

…

Sensor NodesSensor Nodes

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Sensor Node Architecture

Battery powered devices

Batteries cannot be changed nor recharged

Usually negligible

power consumption

Local data processing

and data storage

Short range wireless communication

Radio is the most power hungry component

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Zolertia FireFly

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Telos/Tmote Sky Mote

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Mica Motes

Mica2 Mica2dot

Sensor Board for Micalight, temperature, accelerometer, magnetometer, microphone, tone

detector, 4.5 Khz sounder

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The TinyOS Operating System

Specifically targeted to WSNs

Component-based architecture

Event-based concurrency

Split-phase operation

http://www.tinyos.net/

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TinyOS development environment

nesC language extension to the C language

definition of interfaces

abstraction between definition and composition of components

nesC compiler and OS source composition of the component graph (at compilation time)

TinyOS computational model (additional checks)

TOSSIM simulator same code runs in actual nodes and simulator

flexible models for radio and sensors

scripting (Tython), graphical interface (TinyViz)

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Tutorials on TinyOS Programming Environment

TinyOS/TOSSIM Tutorial,

http://docs.tinyos.net/index.php/TinyOS_Tutorials

TinyOS Reference Manual, http://www.tinyos.net/tinyos-

2.x/doc/pdf/tinyos-programming.pdf

D. Gay et al., "The nesC Language: A Holistic Approach to

Networked Embedded Systems", 2002.

nesC Reference Manual, http://www.tinyos.net/dist-

2.0.0/tinyos-2.0.0beta1/doc/nesc/ref.pdf

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Contiki Operating System

Limited Memory Footprint

Event-driven Kernel

Portability

Many different platform supported

Tmote Sky, Zolertia, RedBee, etc

C Programming

Academic and Industrial support

Cisco and Atmel are part of the Contiki project

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Contiki Operating System

Protothread (optional multi-threading)

Dynamic Memory Allocation

TCP/IP stack (uIP)

Both IPV4 and IPv6

Power profiling

Dynamic loading and over-the-air programming

IPsec

On-node database Antelope

Coffee file system

…

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References

A. Dunkels, B. Gronvall, T. Voigt, “Contiki - a lightweight and flexible operating

system for tiny networked sensors”, IEEE International Conference on

Local Computer Networks, 16-18 November 2004

Contiki: The Open Source OS for the Internet of Things, http://www.contiki-

os.org/

http://en.wikipedia.org/wiki/Contiki

Contiki, Processes. Available Online at:

https://github.com/contiki-os/contiki/wiki/Processes

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Application Areas

Environmental Monitoring

Temperature, Humidity, Light Intensity, …

Presence Detection

Home security systems

Energy efficiency in buildings

Location Detection

Anti-theft systems

Activity Detection

Fall detection

Athlete monitoring

…

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Very Special Sensor Nodes

N. Lane, E. Miluzzo, H. Lu, D. Peebles, T. Choudhury, A. Campbell, A Survey of Mobile Phone Sensing, IEEE Communication Magazine,

Sept. 2010.

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Mobile Phone Sensing Applications

Personal Sensing

personal tracking

Sensing surrounding noise

E-health Fall detection, Activity detection

Well-being support

CenceMe Captures what the user is doing and the information on their surrounding

context (collectively called sensing presence)

Pushes collected information to social networks

EyePhone Allows to activates your mobile phone using only your eyes

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Citizens utilize their mobile phones to send

physical sensing information to a data collection

center

Sensing information can be used for various

applications

Participatory Sensing

Wireless Sensor NetworksWireless Sensor Networks

From Sensors to Sensor Networks 47

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Wireless Sensor Networks (WSNs)

A large number of tiny sensor nodes

deployed over a geographical area

Sensor nodes integrate three different capabilities

Sensing, computing, and wireless communication

Distributed Sensing Infrastructure

Sensor nodes sense physical information …

e.g., temperature, pressure, vibrations, pollution level

… process the data locally …

… and/or send them to one or more collection points

Sink nodes or base stations

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Architecture: Flat Multi-hop

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WSN Application Areas

Military Applications


Precision Agriculture

Location/Tracking

Industrial applications

Health Monitoring

Smart Buildings

Smart Grid

Smart Cities

Smart *

…

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Military Applications

Monitoring

friendly forces,

equipment, ammunition

Battlefield surveillance

Reconnaissance of opposite

forces

sniper detection

Targeting

Battle damage assessment

Attack detection

nuclear, biological, chemical

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Temperature, humidity, pollution level

Habitat monitoring

monitoring of petrel habitat (Great Duck Island project)

Microclimate monitoring

Berkeley botanical garden

Alert systems

fire detection

flood detection

seismic events

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Precision Agriculture

Temperature

Humidity

Wind Speed and Direction

Soil moisture

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Location/Tracking

Location/Tracking of moving objects

Surveillance

Presence assessment

Animals’ movements

Inventory Control

easy localization of items

smart management of items

Vehicles

tracking and detection

car theft detection

remote monitoring of parking places

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Remote monitoring

chronicle patients

physiological data monitoring

elderly people

fall detection

Hospital

monitoring of patients

tracking of doctors and attendants

drug administration

minimize adverse drug events (e.g., allergies to a specific medicine)

E-Health

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Smart Factory

Distributed Intelligent Sensing System for

Factory automation

Process Control

Real-time monitoring of machinery’s health

Detection of liquid/gas leakage

Remote monitoring of contaminated areas

Real time inventory management

…

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Smart Buildings

Building Automation

temperature and air flow control

light level control

energy efficiency

Smart Home

Smart appliances

sensors and actuators inside appliances

easy management of home devices

both local and remote

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Smart Cities


Temperature, Noise, Pollution

Parks and Gardens Irrigation

Parking Area Management

Guidance to free Parking Slots

Traffic Intensity Monitoring

Intelligent traffic management

Mobile Environmental Monitoring

Better coverage than static monitoring

…

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Measured Parameters

Temperature

Light

Noise

CO

…

Light intensity can be used for

smart lighting

If some critical parameters goes

above a threshold the system

sends an alarm.


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Sensors deployed in strategic

(fixed) points

Crosses, bus stops, homes, schools,

…

Measured Parameters

Temperature

Humidity

Air Pollution (PM10, CO, O3, NO2)

Data collection through

mobile elements

public buses, taxis

people

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Sensors deployed also on mobile carriers

public buses, police cars, taxis

people

robots

Measured Parameters

Temperature

Humidity

Air Pollution (PM10, CO, O3, NO2)

Better coverage in a more efficient way


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Goal

to control and make more

efficient the irrigation in

certain parks and gardens

Sensors

Anemometer, pluviometer.

Atmospheric pressure, solar

radiation, air humidity and

temperature sensors.

Soil temperature and humidity

sensors.

Evaluation of water

consumption sensor

Parks and Gardens Irrigation

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Parking areas equipped with

sensors

based on ferromagnetic

technology

buried under the asphalt in

the main parking areas.

provided with one transceiver

send their parking state (free

or occupied), to a gateway

through the repeaters.

Parking Area Management

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Data collected from parking sensors are used to guide drivers towards free

slots, using an architecture divides in two parts:

Panel: Receives information from the Central Station and shows the

number of places available in a determined parking zone.

Central Station: It receives, from the Portal Server, all data retrieved

by the sensors already deployed to detect parking lots availability.

Guidance to Free Parking Slots

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Sensors buried under the asphalt

at the main entrance of the city

Measure traffic parameters:

− Traffic volumes

− Vehicle Speed

− Queue length

Architecture:

− Traffic Sensors

− Repeaters

− Gateway

Traffic Intensity Monitoring

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Readings

P. Baronti, P. Pillai, V. Chook, S. Chessa, A. Gotta, Y. Hu, Wireless sensor

networks: A survey on the state of the art and the 802.15.4 and ZigBee

standards, Computer Communications, Vol. 30 (2007), pp. 1655–1695.

http://www.sciencedirect.com/science/article/pii/S0140366406004749

QuestionsQuestions

From Sensors to Sensor Networks 67

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From Sensors to … … Sensor Networks · PerLab Wireless Sensor Networks Giuseppe Anastasi 3 Overview Sensors Passive Sensors Semi-passive Sensors Sensor Nodes Sensor Platforms