“open source platform for wireless sensor networks” p. papageorgas 1 technological education...

“Open Source Platform for Wireless Sensor Networks”

P. Papageorgas1

Technological Education Institute of Piraeus

1ElectronicsDepartment

eRA6 September 20-21 2011 Piraeus

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“Open Source Platform for Wireless Sensor Networks ”

Aims of this Research Proposal

«For the forthcoming years, a revolution is expected following the continuous convergence of Internet technologies with embedded system technology, creating what experts are referencing as the “Internet of things”» (Sifakis J.- [1])

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The development of an integrated wireless sensor node platform will be performed, targeting to the research through experimentation and education in the associated scientific fields of embedded systems and WSNs.

During the last decade, the rapid evolution in the fields of wireless communications and computing, enabled the development of systems on chip with embedded microcontrollers, wireless modems and sophisticated power management capabilities. The envisagement of “smart dust” and “internet of things” can be realized today with the introduction of advanced CMOS system on-chip wireless nodes, building “ad hoc” Wireless Sensor Networks (WSNs).

A review of the commercial available platforms for wireless sensor networks will be presented focusing in the open source available realizations that are also suitable for higher education in the associated scientific fields.

Aims of this Research Proposal

OPEN SOURCE INITIATIVE

Mission

Open source is a development method for software that harnesses the power of distributed peer review and transparency of process. The promise of open source is better quality, higher reliability, more flexibility, lower cost, and an end to predatory vendor lock-in.

The Open Source Initiative (OSI) is a non-profit corporation with global scope formed to educate about and advocate for the benefits of open source and to build bridges among different constituencies in the open source community.

One of our most important activities is as a standards body, maintaining the Open Source Definition for the good of the community. The Open Source Initiative Approved License trademark and program creates a nexus of trust around which developers, users, corporations and governments can organize open source cooperation.

Open source hardware (OSHW) consists of physical artifacts of technology designed and offered in the same manner as free and open source software (FOSS). Open source hardware is part of the open source culture movement and applies a like concept to a variety of components. The term usually means that information about the hardware is easily discerned. Hardware design (i.e. mechanical drawings, schematics, bill of materials, PCB layout data, HDL source code and integrated circuit layout data) in addition to the software that drives the hardware are all released with the FOSS approach.

Open-source hardwareFrom Wikipedia, the free encyclopedia

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(MCU)Microcontroller

Power Supply, e-metering and Energy Harvesting Circuits

ΤΕΙP_WSN - Node

Interconnection and Debugging

Circuits

UARTs

JTAG

USB

SPI bus

I2C bus

1-Wire

Sensors Signal Conditioning & Interface

Acceleration

Temperature

Ambient Light

Humidity

Current

Voltage

Sensors RF Modem

Interconnection Circuits Digital I/O

Electronic Load DriversExternal Non- Volatile

Memory

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The interconnection of the proposed Wireless Sensor Network with other data networks via the network’s gateway


TEIP_WSN

Node #2

TEIP_WSN

Node #5

TEIP_WSN

Node #4

TEIP_WSN

Node #n

TEIP_WSN

Node #3

TEIP_WSN

Node #1

Gateway

Wireless Sensors Network

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start


Open source WSN platforms & Open Standards

• Cost

• Interoperability

• Customization

• Vendor selection independence

• Continuity

• Community support

• Transparency/Security

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start


Advantages of Open source WSN platforms & Open Standards

Cost :

The hardware design files are freely available, so, one can choose the vendor that will fabricate the designs

This has shown a variaty of prices even for the same product.

Interoperability :

Also aimed by the IEEE 1451 standard.

A WSN platform is a project that must endure the new technologies when they are released.

Open source makes it easy for our platform to adapt a new technology or to be adapted by it.

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start



Customization :

By default, open source platforms are free to customize, to explore their capabilities and to make improvements.

Vendor selection independence :

Open source gives independence from a single producer and the choice of a preferred vendor.

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Continuity :

People can start an open source project based on another open source project. Every useful technology most probably will be used.

Community support :

Dedicated contributors help at the development of the project.Anyone can give feedback.Open source redefines the relationship of the user with the platform

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Transparency/Security :

Everyone knows how the data are processed, where they are going and whether they are safe or not.

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Work performed so far….from first submission…. • State of the art in WSNs, Trends in

Hardware (MCUs, RF modems, Communication protocols in WSNs, OS)

• A first attempt in designing a WSN versatile node

• Arduino an open source platform for WSNs. It’s use for monitoring PVs

• Embedded networking. A Case Study of monitoring a Humidity sensor with an open-source WSN platform and an Embedded Networking platform (Embedded WEB Gateway).

A sensor network is a computer accessible network of many, spatially distributed devices using sensors to monitor conditions at different locations, such as temperature, sound, vibration, pressure, motion or pollutants.

A Sensor Web refers to web accessible sensor networks and archived sensor data that can be discovered and accessed using standard protocols and application program interfaces (APIs). Sensor Web Enablement (SWE) presents many opportunities for adding a real-time sensor dimension to the Internet and the Web. This has extraordinary significance for science, environmental monitoring, transportation management, public safety, facility security, disaster management, utilities' Supervisory Control And Data Acquisition (SCADA) operations, industrial controls, facilities management and many other domains of activity. [2]

..therefore the widespread use of web-enabled wireless sensor networks is mandatory!

Sensor Web

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Trends of Technology

Sensor Web Concept [2]


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IEEE 1451 What is IEEE 1451 ?Standard ways to connect sensors and actuators to networks and systems that facilitate Interoperability

•1451 is a set of network-neutral and vendor-independent transducer interfaces for connecting sensors to networks and instrumentation systems. It aims to facilitate sensor and data interoperability and allows users to get access to sensor data and information seamlessly in both wired or wireless networks and instrumentation systems. It specifies a set of standardized Transducer Electronic Data Sheets (TEDS) format for sensors and actuators. The TEDS contains manufacture-related data for self-identification and self-description.[3]

..so Networking (wired or wireless) of smart sensors can be easy…..



IEEE 1451 Block Diagram (from Smart Sensor Systems)

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IEEE 1451

•Research– Well developed field with many degrees of freedom– Complex, large-scale, resource constrained systems – Focus is on intra network communications

•Development– Solutions are tailored to specific application requirements– Standard compliance (interoperability) – Focus is on communication between WSN and Internet, to facilitate IoT/WoT

•Business– Slowly taking off (evolving standards, endless proprietary solutions multi-vendor interoperability)– Interference and congestion in ISM bands– Huge savings are promised (e.g. smart grids)

A Platform for the Sensor as a Service Concept [10] 7


Current state in WSN

General characteristics and requirements:

•adaptable (diverse application requirements)•periodical, external event triggered and/or on request measurements•asymmetric & directional information flow (centralized, distributed, hybrid data aggregation and network control)•energy efficient (long lifetime, all layers)•scalable (huge number of nodes)•robust (long runtime)•secure (data confidentiality)

A Platform for the Sensor as a Service Concept [10]

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IEEE1451 wireless versions. Zigbee Mesh Network, WiFi, Bluetooth, and 6LowPANare specified under the IEEE 1451.5 standard

(IEEE 1451.4 or Dot 4) DOT 4 – TEDS ONLY VERSIONAnother option is a simplified TEDS onlyversion The Dot 4

Wireless Sensor with Dot 4 TEDS [7]

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Sensor node basic building structure– Power supply– Processing unit– Programming / debugging– Sensors / actuators– Memory storage– Communication interface

Overview of existing sensor nodes [7]

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Power supply• constant power supply (AC-DC, DC-DC, USB)• energy storage devices– rechargeable batteries, non-rechargeable batteries,capacitors, super capacitors, ultracapacitors, fuell cells,etc.• energy harvesting– solar, thermal, wind, vibration, electromagnetic, kinetic,etc.


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Processing unit• Microcontrollers• Field-Programmable Gate Arrays (FPGAs)• Digital Signal Processors (DSPs)• 8 bit, 16 bit, 24 bit or 32bit architecture• Texas Instruments, Atmel, PIC, ARM etc.


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Programming /debugging• JTAG• Serial• Parallel• Over the air


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Sensors / actuators• Sensors: temperature, humidity, light, pressure, etc.Others ???• Actuators: relays, speakers, etc.

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Memory storage• Memory:– Internal / external– Volatile / non-volatile

• if large capacity is needed– Compact Flash, SD, mini SD, micro SD, PCMCIA, etc.

• If smaller capacity is needed– FLASH, SDRAM, EEPROM, etc.

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Communication interfaces• Wired communication interfaces– RS232, Ethernet, I2C, SPI, etc.

• Wireless– RF interfaces (ISM band - interference)• Sensor networks dedicated• GSM/GPRS• etc.– optical interfaces (sensitive to atmospheric conditions)– ultrasound (underwater)

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Operating systems for embedded hardware

• TinyOS

• Contiki OS

• BertOS

• uClinux

• Android

Operating systems designed specifically for WSN applications with hardware limited resources (computing power, energy consumption):

All are free & open sourceWe choose depending to our

needs ..and resource limitations

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Operating systems for embedded hardware

The selected OS must have features like:

•Low power consumption

•Multithreading/Multitasking design

•I/O handling

•Networking (IPv4/IPv6)•Small MEMORY footprint….

Nodes roles and their estimated capabilities according to standards [7]

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General gatewaybasic building structure [7]

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Hardware analysis procedure• > 125 sensor nodes identified [7]

– processing units (number, type, clock, FLASH, ROM, RAM, SRAM, EEPROM),– power consumption– wakeup times,– communication standards/technologies,– communication interfaces– external memory units– programming interfaces – sensors/actuatorspower supply, USB, energy harvesting, batteries),– year of development,– developers and/or manufacturers.

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SOC MCU and RF modem [Texas Instruments]

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Data-rates– high data-rates (i.e. > 1000 bps)• IEEE 802.11 units– adapted general-purpose computers (Wi-Fi routers)» usually constant power supply– adapted general-purpose computers (smartphones) and embedded sensor nodes» rapidly consume battery power

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Results – communication interfaces [7]

Data-rates– medium data-rates (i.e. ~1000 bps)• Bluetooth radios– usually do not require constant power supply and can last on battery power for a while– low data-rates (i.e. ~100-250 bps) data-rates < 100 bps data-rates of only few bps (SpotON, PC 104+, etc.)• dedicated RF interfacesShould be interpreted as real “low-data rates”.

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• 13 % SoC (processing unit/radio) chips operating as RF units • 5 % more than one communication unit• 13 % produced in various hardware versions with various RF units• 44 % external antenna (whip)• 36 % onboard antennas (PCB, chip)• 17 % both antenna types supported • 3 % of the nodes do not have antenna, but are equipped with optical or wired communication interfaces

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start

front view

rear view

WSN-Node• 2.4GHz

• 100m Distance Range

• Low Power Consumption

• Small Form-Factor

ZigBee Interfacing (A first successful attempt in TEIP… (Pyromalis et.al.)


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Arduino Electronics prototyping platform (hardware is using Atmega328)

Free and Open source software and hardware

Community-based project

Arduino Shields - extention boards (Ethernet, Xbee)

Zigbee coordinator node : retrieves measurement data from end devices of the PV array

Internet Client for Pachube via Ethernet

Simple means coding faster (compile with GNU toolchain and AVR Libc)

Syntax and libraries in Wiring language (based on C++)

COTS WSN Gateway Platform (Open Source)


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Examples of applications with Arduino


o Wearable/Stichable applications (with Lillypad Arduino)

o Medical monitoring

o House wireless automations

o Sensors and actuators communication (ThingSpeak, Pachube)

o Sensor data routing (Arduino as a standalone server)

o ...Radiation data sharing (used in recent Fukushima disaster)

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• Internet of things (e.g. sensors)

• Sharing and storing data (energy/sensor/environment data) in applications (pc or mobile, with use of applications or in maps)

• Ease-of-use, security & scalability

Remote monitoring and control by any system

• Multiple features : log, Triggers, Geo-location, Augmented reality view, SMS alerts

• Request per minute limit : 3 minutes (depenting on account type)

WEB-Based Data Monitoring and Control


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WEB-Based Data Monitoring and Control


ThingSpeak is yet another fully open source solution:

The user can setup his own server to collect/log, visualise his sensor data and handle actuators.

Source code available on GitHub.

Both Pachube and ThingSpeak communicate with Arduino using RESTful design(only GET, PUT, POST, DELETE)

• Low Power: a TI proprietary low-power RF network protocol

• Low Cost: uses < 8K FLASH, 1K RAM depending on configuration

• Flexible: simple star w/ extender and/or p2p communication

• Simple: Utilizes a very basic core API

• Low Power: Supports sleeping devices

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SimpliciTI Interfacing. An open-source WSN platform

SimpliciTI™


An Embedded WEB server for Humidity sensing using open-source platforms

[POULIZOS M. and P. PAPAGEORGAS 2011 Master Thesis\

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SimpliciTI Network topologywireless sensing application


• Range can be

extended through

repeaters.

• The circles

represent range

of gateway and

extended range of

repeaters.

3

SimpliciTI Architectural Overview


Network Support

init

ping

link / linklisten

Layers

MRFI (“minimal RF

interface”)

NWK

nwk applications (modules)

customer applications

nwk mgmt

send / receive

I/O

• CC2500 - 2.4 GHz, ISM band multi-channel low power transceiver

•2 LEDs

•1 pushbutton

•Supports development with some 2xx Spy Bi-Wire devices

•Supports MSP430 Application UART allowing serial communication to PC

•Supports eZ430-T2012 and eZ430-RF2500T target boards

•Removable USB stick enclosure

•SimpliciTI, low power network stack

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MSP430 Wireless Development Tool eZ430-RF2500


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Internet Enabled Embedded SystemEmbedded System for Data Retrieval over WSN


• WSN End Device

with Sensirion

temperature and

humidity sensor

• WSN Access

Point

• Internet Gateway

based on

iMCU7100 EVB

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Internet Enabled Embedded SystemEnd Device – Sensirion Sensor SHT21 - Digital Humidity Sensor


•Output: I2C digital, PWM and SDM/analog Volt

interface

•Energy consumption: 3.2uW (at 8 bit, 1

measurement / s)

•RH operating range: 0 – 100% RH

•T operating range: -40 – +125°C (-40 – +257°F)

•RH response time: 8 sec (tau63%)

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Internet Enabled Embedded SystemApplication Development - KEIL μVision4 IDE


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Internet Enabled Embedded SystemApplication Development - IAR Embedded Workbench


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Demonstration Applications described in the project proposal

•Preventive monitoring of PV panels Development of all the necessary hardware extension modules and the appropriate web-based tools for data communication and publishing with remote computers. In this demonstration application a miniature data-acquisition system will be integrated to the platform with an appropriate electronic load for PV panel characterization [6].

•e-metering of home appliances power consumption.


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Results expected from the project

• The basic hardware and software platform for the wireless sensor node with the associated documentation and Application Programming Interface description.

• The documentation concerning the programming of the gateway platform based on a COTS system.

• The documentation for the data transfer, publishing and remote management of the WSN using an open source web-based data transfer platform.

• Demonstrator application documentation for the remote monitoring of a distributed power generator as a PV panel, using the developed WSN node and the associated gateway and web-publishing platforms.

• Demonstrator application documentation for the remote monitoring of an electronic metering module for electric power consumption using the platform developed.

• The documentation for a set of laboratory exercises for programming of embedded microcontrollers and wireless sensor networks, as well as the remote management and monitoring of WSNs.


State of the Art (Google….)Google Sky Map for the open-source OS Android

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GOOGLE’S Android@Home [9]

• Google Earth Google Sky Google Sky Map for Android. You just point your phone at the sky to see annotations associated with the stars, planets, constellations, and more…

• Android@Home WSN and SNAP. The idea is that, in the not-so-distant future, the entire home will be seen as a network of accessories that can be discovered and communicated with by Android Apps running on an Android device like a smartphone or a tablet computer.

•Synapse’s technology, SNAP, was possibly the most overlooked actor in the Hollywood blockbuster film Tron: Legacy. Tron, noted for its stunning visuals, used SNAP to control the lighting of the actors’ signature suits.

• Google has already mentioned their plans to come up with an open source WSN platform and Google says that they will make this platform available, free of charge, to hardware manufacturers of wireless home network devices, just as they did with the Android platform to handset manufacturers. This can open up a huge business opportunity for Google to repeat the “App Store” model for WSN/IoT (“Internet of Things”) • Google is now officially jumping into the home automation market, what is also interesting to us is the news that Google is developing a “new wireless mesh network” technology (i.e. Wireless Sensor Network – WSN) [SOURCE: 17 JULY 2011] http://blog.millennialnet.com/2011/07/13/where-is-google-going-with-the-android-home-initiative/


Graphical representation of a

Graphical representation of a Low-power Wireless Area Network (LoWPAN)

open standard known as 6LoWPAN to connectInternet-level networks with LoWPANs

Graphical representation of the difference between ZigBee and a SNAP-based wireless node. [8]

ZigBee is NOT OPEN

SNAP-enhanced 6LoWPAN platform [8]

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eRA6 September 20-21 2011 Piraeus 17

Acknowledgements

This research has been supported through the Operational Program "Education and Lifelong Learning" and is co-financed by the European Union (European Social Fund) and Greek national funds.


eRA6 September 20-21 2011 Piraeus 17

References

1. Sifakis J., “The Internet of Things” – Turing price in Information Technology, Eleutherotypia -14/03/2009

2. Mike Botts, George Percivall, Carl Reed, John Davidson “Sensor Web Enablement: Overview And High Level Architecture” Open Geospatial Consortium Inc. White Paper, Ref. number: OGC 07-165, 2007

3. Kang Lee “Enabling the Smart Sensor Revolution - IEEE 1451 Standards” Session: An Open Standards Infrastructure For Homeland Security For Sensor Network Interoperability, SensorsGov Expo/Conference, Dec 6-8, 2005, Hampton, VA

4. IEEE 1451 information http://ieee1451.nist.gov5. Darold Wobschall, “IEEE 1451 -- A UNIVERSAL TRANSDUCER PROTOCOL

STANDARD”6. http://era.teipir.gr/era5/era5_pro.doc7. Marko Pesko “Overview of existing sensor nodes” Agrosense 19/10/20108. Clive Maxfield “IPv4, IPv6, The Internet of Things, 6LoWPAN, and lots of other “Stuff”

EETIMES 7/7/20119. Clive Maxfield “Rumors abound with regard to Google’s Android@Home” 6/20/201110. Miha Smolnikar “Versatile Sensor Node. A Platform for the Sensor as a Service

Concept “Wireless sensor networks & Small medium enterprises (WSN-SME): ProSense workshop, May 2010


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Thank You!

eRA6 September 20-21 2011 Piraeus


“open source platform for wireless sensor networks” p. papageorgas 1 technological education...

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