Transcript SoftwareFreedomDay-S.. - The University of Sydney

SunSPOTs
At Sydney University
by Tim Dawborn
Agenda
What are SunSPOTs?
 What are we doing with them?
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 Corona
 SPOTCopter
What are SunSPOTs?
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A SunSPOT is a small electronic device
made by Sun Microsystems
They have a variety of sensors
attached to it
SunSPOTs are programmed in a Java
dialect, with the Java VM run on the
hardware itself
(“bare metal”)
What are SunSPOTs?
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Java “Squawk” VM
180 MHz 32bit ARM920T core
512K RAM
4Mb Flash Memory
2.4 GHz IEEE 802.15.4 radio
USB interface
2G/6G 3-axis accelerometer
Temperature, light, touch sensors
5 IO pins and 4 output only pins
What are SunSPOTs?
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SunSPOTs communicate wirelessly to
one another via the 802.15.4 “Zigbee”
protocol
Putting many of these SunSPOTs
together forms a Wireless Sensor
Network (WSN)
Wireless Sensor Networks
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“A wireless sensor network (WSN) is a
wireless network consisting of spatially
distributed autonomous devices using
sensors to cooperatively monitor physical
or environmental conditions, such as
temperature, sound, pressure, light,
motion or pollutants, at different
locations”[1]
Most WSN platforms are programmed in a
C dialect called nesC
[1] http://en.wikipedia.org/wiki/Wireless_sensor_network
What are we doing with them?
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Corona: SunSPOT Distributed Query
Processing System
 Project
started in 2006
 Being open sourced early in 2009
 A query processing platform for a
SunSPOT WSN
Corona
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Original Architects:
Raymes Khoury
 Tim Dawborn
 Edmund Tse
 Dr. Bernhard Scholz
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Core Developers:
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Raymes Khoury
Tim Dawborn
Other Important Contributors:
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Dr. Uwe Röhm
Saeed Attar
Khaled Almi'Ani
Glen Pink
Corona
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What is a distributed query processor?
 Make
the WSN act like a table in a
relational database
 Corona allows queries to be formulated in
an SQL-style syntax, which are fed to the
SunSPOT network to be executed, for
which a table of results is retrieved
 Example:
SELECT temp, light
FROM network
WHERE temp > 25
Corona
Corona
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Corona is a resource-aware system
 Resource
awareness is a key aspect of
WSN programming
 Using the wireless to communicate
between nodes is the most costly
operation on the SunSPOTs
 WSN nodes should be deployed once
and last a long time without having to
be physically altered
Corona
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Distributed relational database issues
 How
can you do relational operations
such as “AVERAGE(light)” in a
distributed environment?
 How can you do subqueries in a
distributed environment where network
transmission is very costly?
SELECT node, parent
WHERE light >
(SELECT MAX(light) GROUP BY temp)
Corona
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Resource-aware networking issues
 How
should you detect new nodes in the
mesh network when transmission is
costly?
 Being a “distributed database” system,
what should happen if a bridge node in
the network drops out in terms of the
data in the now isolated component of
the network graph?
What are we doing with them?
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SPOTCopter: Remote Control
Helicopters
 INFO1905
Advanced first year project
this semester
 Aim is to get the user to specify the
height to hover at from a desktop
computer, and to make the SunSPOT
mounted to the helicopter perform this
action
SPOTCopter
Flying a helicopter is easier said than
done – unstable system
 SunSPOT platform does not have
proper floating point numbers
 SunSPOTs have a slow clock speed
so solving differential equations of
motion in “real time” has issues
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SPOTCopter
SPOTCopter
SPOTCopter
A project still in the making
 By the end of the year there will be a
Youtube video of our SPOTCopter
flying
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Conclusion
SunSPOTs are a nice platform for
working with WSN technologies
partially due to using Java over nesC
 WSN is an new and exciting research
area
 WSN technologies have a lot of real
world applications
 http://www.it.usyd.edu.au/~wsn
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