MICA: A Wireless Platform for Deeply Embedded Networks

By Jason L. Hill, David E. Culler

Presented By Charuka Silva

Application Possibilities for Miniature Wireless Sensing

Devices• Road side traffic pattern and open parking

spot detection

• Individual plant monitoring for precession agriculture

• Advanced building security and automation

• To gauge the structural integrity of building and bridge after earthquakes and fires

Low Power Peer to Peer Ad-hoc Networks

• Local communication and application specific protocol drastically reduce size , cost and power use

• Peer-to-peer networking techniques provide flexible mesh like interconnect, which shuttles data between thousands of tiny embedded devices

Ad-hoc Wireless Embedded Network For Precession

Agriculture

Contd..• Sensors detect

– Temperature– Light Levels– Soil Measure at hundreds of points accrossed

the field

• New algorithms for data aggregation, ad-hoc routing and distributed signal processing for low power peer to peer ad-hoc networks

MICA Wireless Platform

• Measures 1.25 X 2.25 inches• Runs TinyOS operating system• Suited for self configuring multihop wireless

networks• Has sensing, communication and I/O capabilities• Simultaneously act as a data router, sensor

interface and control point.

Contd…• To explore novel systems approaches,

researchers can develop customized protocols tailored to their application; Mica does not require use of predefined protocols.

• provides a set of richly interconnected primitives (such as data serializers and timing extractors) to facilitate cross-layer optimizations.

Contd..

• Design of power and time efficient primitives improve key system capabilities including low power device startup, time synchronization, power aware routing and localization.

• The standby current for MICA’s components is few microamps; can run application several years on one battery.

Contd..

• Expansion bus connects to wide array of sensors improving experimental flexibility.

• Batch of sensor board include support for monitoring thermal temperature, barometric pressure, magnetic fields, light, passive infrared frequency, acceleration, vibration and acoustics

MICA Node

Wireless Design Comparison For Deeply Embedded Systems

1. Power consumption must be drastically reduced.

– Power consumption must average in the microamps range, requiring powering down most of the device much of the time

2. Many deeply embedded systems cannot rely on a predeployed, powerful infrastructure for support.

Contd..– In a peer-to-peer multihop network, typically,

only the last hop communicate with the base station

– most of the nodes would be located outside of the station’s direct communication range.

• Most wireless devices carry out a single, highly standardized function.– deeply embedded networks must be

suited to a wide variety of applications; requires a more general-purpose system design.

MICA Block Diagram

MICA Architecture Overview

• Consists of five major modules– Processing– Power Management– I/O Expansion– Secondary Storage

• Processor– The main microcontroller is Atmega 103L

– Normally programmed at manufacturing time, but MICA enables dynamic re-programming during routine use.

– Coprocessor handles wireless reprogramming.

• MICA Radio Module– RF Monolithics TR1000 transceiver and set of discrete

components

– Software can externally set the transmission radius ranging from inches to hundred feets

– Radio interface give direct control over the transmitted signal,allowing the modulation scheme, coding, framing and MAC protocol to be determined in software

• I/O Expansion– Use to interface variety of sensing and

programming boards.– Expansion connector can program and connect

to other devices. Eg. PC as a gateway– Can control or provide data to any RS-232

protocol based device.

• Power Management– Regulate system’s supply voltage– Operates with inexpensive alkaline batteries

• Storage– 4Mbit Atmel AT45DB041B serial flash is used– Stores sensor data logs and temporarily holds

program images received over the network interface.

Today’s MICA

• Many research groups in the US that are exploring deeply embedded sensor networking use MICA node as a foundation for their researches

• A single-chip version of the architecture is in development. It will generalize MICA architecture, provide additional accelerator and drastically reduce standby power consumption.

Thank you