report on sensor networks
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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
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