Embedded operating system

An embedded operating system is an OS for embedded computer systems.So that it is so small. Especially in sensor networks have sensor nodes whose memory and RAM is tiny.
How to small embedded operating system is a problem on air.

New year in Japan ^_^ 明けましておめでとう！！！

At present,I have been studying in Japan.So that this year is the first time I had a party new year overseas.Waiting for the new year 2010,playing the card game with my friend,sitting next to my girlfriend...I felt so happy.I wish my friend always happiness and success...wish my girlfriend always smiling, health and for getting new successes.

What is TinyOS?

When you see the "TinyOS" word, you think what is it? Maybe you're same with me. Because the "TinyOS" word consists of "OS", the first time I think it it a operating system like Windows OS,Mac OS...
TinyOS is an embedded operating system written in the NesC programming language.It is a free and open source component-based operating system and programming platform for WSN (wireless sensor networks).
TinyOS is started as a collaboration between Intel Research at University of California,Berkeley and Crossbow Technology,and has grown to be an international partnership,the TinyOS Alliance.

NesC is same C???

The first time I heard the "NesC" word from my senior I think NesC may seem C programming.But after searching and learning some examples of NesC,I think NesC is not same C except basic commands.
NesC is developed from C but Why NesC is not same C? NesC is used to build applications for the TinyOS platform and running on sensor nodes.It is built as an extension to the C programming language with components "wired".
If you are a newcomer in the NesC language,there are 2 conceptions I think you feel difficult to understand.They are "components" and "interfaces".

• Components: a NesC application consists of one or more components assembled or wired to form an application executable.A component provides and uses interfaces.
• Interfaces:a set of commands and a set of events

the detail explanation of above conceptions at address: TinyOS Documentation

Iris Mote

Do you know what is Mote? In dictionary mote means a small particle.In a WSN(wireless sensor networks) mote is a device takes a sensor and sends data from this sensor to a gateway.Like the definition of mote in dictionary the Mote in WSN is quit small.
The development of the mote is increasing integration as dictated by Moore's Law,is smaller,faster and more numerous.
I'm using Iris Mote,a famous mote in the world,so that I will show you the characteristic of Iris Mote below.
Iris Mote is developed by Crossbow Technology,built upon the IEEE 802.15.4 standard.It is regarded as the successor of MICAz,one of the most commonly used mote systems in the world.
The spec of Iris Mote:

• AtMega1281
• Program flash memory with 128K
• Using radio RF230 2.4GHz
• IEEE 802.15.4
• Output 3dBm

Supported by TinyOS 2.x,Xmesh(MoteWorks),SOS,LiteOS,Mantis and Contiki

-> Iris Mote -> Programming board mib 520


->Base Station (receives signal from motes and sends packets to computer)

Notes from my experience maybe is so useful for newcomers:

• Installing a program on iris mote: "make iris install mib520,serialport",for example if you use VMware, a command like "make iris install mib520,/dev/ttyUSB0"
• Let's use the Blink example as the first example.I think this example very useful for newcomers.

PS: "iris means an eye :D"
Thx for reading my blog ^_^

RSSI FingerPrinting and Localization in WSN

WSN(Wireless Sensor Network) is a network includes sensor nodes,gateways and communication between sensor nodes is radio.In a wireless sensor network,if you want to localize where a node is is so difficult because there are many sensor nodes wherefore Localization in WSN is a problem needs accurate solutions.
At present there are a lot of algorithms for how to localize for example classical algorithms (Triangulation,FingerPrinting...), recently algorithms(RFID...).In this post I will introduction FingerPrinting algorithms by using RSSI (so called RSSI Fingerprinting).
This algorithm is divided in 2 phases:

1. Creating Fingerprinting database(called offline phases): It means the RSS is measured at each predetermined location to create a database of RSS patterns.The database of RSS patterns is called a radio map.
   
2. Location estimation(called online phases):It means from received RSS will compare with the database of RSS patterns and use a positioning algorithm to estimate the location of the mobile station.

The advantage of this algorithm is that not require the mobile station to see at least three base station in order to determine the location.
The disadvantage of this algorithm is that it is very time-consuming to perform an exhaustive data collection.

PS:My english really is so bad...Thx for reading!