Generic Sensor Platform for Networked Sensors

Haywood Ho

August 7, 2002 Wireless Sensor Networks

Introduction

• Smart Dust• TinyOS• Generic Sensor

August 7, 2002 Wireless Sensor Networks

‘Smart Dust’

• MICA• ATMEL

ATMEGA103 4MHz processor

• 512 KB flash memory, 4 KB RAM

• A/D converter• Network

reprogramming• Battery• Radio (916 MHz)

August 7, 2002 Wireless Sensor Networks

August 7, 2002 Wireless Sensor Networks

Overview of TinyOS

• Tiny, Microthreaded, Operating System

• Designed specifically to meet constraints of sensor networks– Robust operation– Low computational power– Low power– Little memory

August 7, 2002 Wireless Sensor Networks

Tiny OS – The Software• Component based model• Abstracts hardware specifics from

application programmer• Capable of maintaining high levels of

concurrency• Services Provided Include:

– RF messaging protocols.– Periodic Timer Events.– Asynchronous access to UART data transfers.– Mechanism for Static, Persistent Storage.

• Complete applications fit in 4KB of ROM and 256B RAM

August 7, 2002 Wireless Sensor Networks

Generic Sensor Platform

• Currently, three types of messages

• A “network discovery” packet• Data packets• Generic Sensor command packets

August 7, 2002 Wireless Sensor Networks

Generic Sensor: Overview

• Matlab front-end to allow application developers to control motes

• Integrates many pre-existing applications to allow motes to be programmed with Matlab instead of TinyOS code (abstraction)

• No need for network reprogramming• Library of data analysis tools in Matlab

August 7, 2002 Wireless Sensor Networks

Architecture

OSCOPE LEDS RADIO LOGGER SLEEP

COMMAND OSCOPE

BCAST AM_ROUTE

GENERIC_COMM

OSCOPE LEDS RADIO

COMMAND

GENERIC_COMM

August 7, 2002 Wireless Sensor Networks

Network Discovery: Radio Cells

August 7, 2002 Wireless Sensor Networks

Network Discovery

August 7, 2002 Wireless Sensor Networks

Network Discovery

• Simple routing algorithm to form routing tree

• No cycles• Over rebroadcasts

August 7, 2002 Wireless Sensor Networks

OSCOPE Data Packets

• Routed back to the base station using stored route from network discovery

• Data can then be captured and visualized in real-time in the Matlab environment

August 7, 2002 Wireless Sensor Networks

Demonstration

August 7, 2002 Wireless Sensor Networks

Conclusions

• Generic Sensor platform allows faster deployment of sensor networks

• Allows application programmers to abstract away from lower-level details of TinyOS

August 7, 2002 Wireless Sensor Networks

Further Work

• Log and Sleep• Simultaneous sensing from different d

ata channels• Time synchronization issues between

motes• Robustness• Alternative ad-hoc routing alogirthms