1. ODBC interface for Remote Wireless Sensor Network
Jun Ma

2. What is Wireless Sensor Network
This wireless sensor is called a “mote”. It’s a small-scale computers with sensors, a microprocessor, RF communication and battery.
It is intended to be very small and very cheap so that it can be massively distributed.

3. What is Wireless Sensor Network
A number of wireless sensors forms an wireless adhoc network which provides functionality like message routing.
WSN can be used in a wide range of applications, including environmental monitoring, surveillance, smart buildings, health, traffic monitoring, and military systems.

4. What is Remote WSN
A wireless sensor network deployed at very remote locations.
Data is collected remotely through telephone network like GPRS or CDMA.

5. A Database for WSNs
TinyDB is a database system written in java for extracting information from a WSN.

6. Project Motivation
We can’t interface with WSN like a standard database.
WSN can be much easier to use if it could be used directly from the standard tools for programmatically interfacing with database.

7. Objective
Improve usability of WSN by providing a standard ODBC interface between TinyDB and most normally available database tools.
Map the sensor network to a database paradigm.
Make the whole sensor network looks like an standard database table.
Node ID
Temperature
Humidity
Light
Sound 1
21.5 13 67 34 2
22.2 14 56 40 3
23.8 12 77 21

9. Software platform An ODBC driver for Windows platform.
Wireless sensor runs TinyOS which is an open-source operating system designed specially for wireless embedded sensor networks.
GPRS modem runs Nut/OS which is an open-source operating system designed for Atmel microcontroller.
TinyDB which is a database engine for WSN.
TinyDB proxy which is a java application which translates SQL query into something motes can understand.
Programming language: C, C++ and Java

10. Driver Development An ODBC driver is a DLL on windows platform.
The driver implements functions specified in the ODBC standard.
The driver must make sure the ODBC functions are called in correct sequence.
Sending query to TinyDB Proxy server
Retrieving data from the XMLBlaster server.
Decoding TinyDB binary messages.
Mapping errors to ODBC SQLSTATEs.

11. Programming Considerations
Make the ODBC driver fully thread-safe, so that the driver can handle an ODBC call from any thread at any time .
The ODBC driver resides in the same memory space of the user application.
All the ODBC functions must be exported with its original name using a module-definition (.DEF) file instead of __declspec(dllexport).
A event logger is needed for debugging.

12. Research issues Supporting TinyDB specific SQL .
How effectively can a sensor network be mapped to database paradigm.
Balancing query latency vs. power consumption.

13. Supporting TinyDB specific SQL .
If a query contains TinyDB-Speicific SQL, the driver sends it to TinyDB proxy for processing.
A SAMPLE PERIOD is appended to SQL queries if it doesn’t exist.
Replace “*” in the query with a list of all available attributes in the sensor network.

14. Mapping sensor network to database paradigm
Step 1: Connect
SQLAllocHandle(ENV)
SQLSetEnvAttr
SQLAllocHandle(DBC)
SQLDriverConnect
SQLSetConnectAttr
SQLGetInfo
SQLGetFunctions
SQLAllocHandle(STMT)
SQLSetStmtAttr
Step 2: Building and Executing an SQL statement
SQLTables
SQLNumResultCols
SQLDescribeCol
SQLBindCol
SQLFetch
SQLExecuteDirect
Step 3: Fetch result
SQLNumResultCols
SQLDescribeCol
SQLBindCol
SQLFetch
SQLGetData

15. Balancing query latency vs. power consumption.
Polling instead of continuous sampling saves power.
Changing the schedule scheme to balance power consumption vs. latency.

16. Summary
With an standard ODBC interface, Wireless Sensor networks have greater usability, functionality, extensibility and ease of integration.
However some new restrictions like large latency and difficulties with event driven sampling are introduced.

17. Any Questions?

19. Function Sequence
Applications retrieve data from ODBC driver by calling functions in a certain sequence.

20. Decorated Name DEF file LIBRARY ODBCWSN EXPORTS ;SQLAllocConnect @1
EXPORTED FUNCTION
ORDINAL
DECORATED NAME
Prod 1
Sum 2
CMyClass::CMyClass() 3
CMyClass::~CMyClass() 4
CMyClass::operator= 5
CMyClass::SAbout() 6
CMyClass::SHowdy() 7
LIBRARY ODBCWSN
EXPORTS

21. TinyDB packet