Report onSensor Networks

By

Ganesh Godavari

Tuesday, Feb 17, 2004

Sensor Networks

• Basic Subsystems of Motes– Power: sensor motes don’t have the ability to monitor

an environment for unlimited time as they only have limited energy.

– Computation: Sensor motes are required to process sensor data and communicate with others. Their computation power of the motes is very less compared to any desktop.

– Sensors: sensor motes have the basic sensors for sensing the environment like temperature, pressure, humidity, sound, acceleration.

– Communication: communication must be possible between the motes separated by a range of few meters.

Focus of our project

• Goals of First Responder Sensor Network (FRSN)– Information Gathering : get information about

temperature from each mote and display information

– Tracking : ability to monitor movement of motes

Equipment Used

• Stargate: XScale Network Interface and Single Board Computer used as gateway.

• Wireless Measurement System – Mica2– Micadot

Stargate MICA2 MICA2DOT

Contd..

• Programming Interfaces Available– MIB500 – Parallel Port Programming Interface

Board – MIB510 – Serial Port Programming Interface

Board

Stargate

• Operating System : Linux 2.4.19-rmk7-pxa1

• Network Interfaces : wired Ethernet 10/100 Base-T port

Information Gathering

• Application must have – Ability to form a network dynamically

(ADHOC)– provide information to the Gateway

• Role of Gateway– Must gather information – Send information to a set of Wired/wireless

clients

Existing applications/libraries

• TinyOS-1.1 provides adhoc routing libraries which use– Shortest Path First algorithm– Active two-way link estimation– Example Surge Application– Limitations : higher message frequency can

lead to data congestion

Contd..

• Application – SerialForwarder : read data from the serial

port – Listen: connects to the SerialForwarder and

displays the information– Surge: displays information in GUI format for

better visualization

Applications Stargate

• Stargate came with– “Hello World” Application– Networking Application– File System Application– Webcam video-capture application– Mote Application

• Missing is the forwarder application.

Current work

• Working on writing a forwarder application that forwards data received on the serial port.

• Did preliminary analysis on the working of serialforwarder.

• Failed to port wonka jvm onto stargate.

• http://wonka.acunia.com/ doesn’t seem to be right.

Message structure TOS_Msg

typedef struct TOS_Msg{uint16_t addr; uint8_t type; uint8_t group; uint8_t length; int8_t data[TOSH_DATA_LENGTH]; uint16_t crc;} TOS_Msg;

Message Structure TOS_MHopMsg

typedef struct MultihopMsg {

uint16_t sourceaddr;

uint16_t originaddr;

int16_t seqno;

uint8_t hopcount;

uint8_t data[(TOSH_DATA_LENGTH - 7)];

} TOS_MHopMsg

Captured data analysisCaptured a multihop message of surge

7E 42 7D 5E 0 11 33 C 0 0 0 0 0 0 0 0 EC 0 7D 5E 0 13 6C 7E

7E indicates the beginning of the frame42 indicates A data packet that does not require a subsequent ACK packet

(tinyos documentation)7D indicates that the preceding byte needs to escaped i.e preceding byte

needs to be xor with 0x20 and is not counted5E 5E xor 20 = 7E // beginning of the tos packet 0 00 the second part of the tinyos message11 decimal value 17 indicates its a multi hop packet33 group idc decimal value 12 is the length of the dataso the data is

Contd..

0 0 source address of the multihop message

0 0 original address of the multihop message

0 0 sequence number

0 hop count

0 EC 0 7D 5E data part of the multihop message

0 13 is the CRC of the tinyos message

6C 7E is the part of the frame

stargate and Java Virtual Machine (JVM)

• open wonka jvm– acunia technologies– can run on the arm architecture machines.– Wonka

• fsroot directory– contains important classes for the system.

• wonka bin file – wonka reads all classes inside the fsroot directory

installing SerialForwarder on stargate

• Serial forwarder application– tools/java/net/tinyos/sf directory.– copy the class files in net directory and its

subdirectory in to fsroot directory– Remove the ‘(‘, ‘)’ braces in device.config file

for the serial devices you are going to use for both attach-serial-device, and register-serial-device line.

– wonka <serialforwarder filename>

Displaying data on host/remote pc

• Environment variable – “MOTECOM” – Tells where the serial forwarder is running– export

MOTECOM=sf@testABC.domainname:9001

Current activities

• Looking into the tracking

References

• http://cs.uccs.edu/~frsn/docs/nisscReport.doc