Report on Sensor 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 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. 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 analysis Captured a multihop message of surge 7E 42 7D 5E C EC 0 7D 5E C 7E 7E indicates the beginning of the frame 42 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 counted 5E 5E xor 20 = 7E // beginning of the tos packet 0 00 the second part of the tinyos message 11 decimal value 17 indicates its a multi hop packet 33 group id c decimal value 12 is the length of the data so the data is

Contd 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

Displaying data on host/remote pc Environment variable –“MOTECOM” –Tells where the serial forwarder is running –export

Current activities Looking into the tracking

References doc