Ingenieria

Telos: Enabling Ultra-Low Power Wireless Research
Joseph Polastre, Robert Szewczyk, and David Culler
Computer Science Department
University of California, Berkeley
Berkeley, CA 94720
{polastre,szewczyk,culler}@cs.berkeley.edu

Abstract— We present Telos, an ultra low power wireless sensor module
(“mote”) for research and experimentation. Telos is the latest in a line
of motes developedby UC Berkeley to enable wireless sensor network
(WSN) research. It is a new mote design built from scratch based on experiences with previous mote generations. Telos’ new design consists of three
major goals to enable experimentation: minimal power consumption, easy
to use, and increased software and hardware robustness. We discuss how
hardware components are selected and integrated in orderto achieve
these goals. Using a Texas Instruments MSP430 microcontroller, Chipcon
IEEE 802.15.4-compliant radio, and USB, Telos’ power profile is almost
one-tenth the consumption of previous mote platforms while providing
greater performance and throughput. It eliminates programming and
support boards, while enabling experimentation with WSNs in both lab,
testbed, and deployment settings.I. I NTRODUCTION
Wireless sensor networks are ideally suited for long-lived applications deployed at large densities for low cost. Unfortunately, the
current WSN platforms built from commercial off-the-shelf (COTS)
components have a lifetime of no more than two years, communicate
through non-standard interfaces, are expensive, and are difficult to
use for experimentation, development, testing,and deployment.
In this paper, we introduce the design of Telos, the latest wireless
sensor device, or “mote”, from the University of California, Berkeley.
Telos (shown in Figure 1) is a new design to further research in sensor
networks with three major goals: lower power operation than previous
mote generations, easy to use, and robustness for experimentation
and deployment. The Telosdesign is based on the following low
duty cycle principle: the node is asleep for the majority of the time,
wakes up quickly on an event, processes, and returns to sleep. For
the lowest power consumption, the standby current and wakeup time
(time to transition from sleep to active mode) must be minimized [1]
since the the active portion of a sensor network application is
typically extremely small[2]. Telos offers more than just low power
operation through its integrated design. Integration of programming,
communication, storage, and sensing allows researchers to utilize
more functionality and develop more robust systems.
II. R ELATED W ORK
The lineage of current platforms can be traced back to a number
of devices called “COTS motes” built by the SmartDust project
and shown inFigure 2. These devices were built to approximate
the capabilities of an envisioned SmartDust node with off the shelf
components [3]. These designs used a small 8-bit microcontrollers (4
to 8 kB of flash, 512 bytes of RAM); a simple radio (OOK modulation
at 4kbps) and integrated sensors (magnetometers, accelerometers,
temperature, pressure, etc). Later designs (weC [4], and Ren´ )
e
exposed acustom sensor interface and allowed for the possibility
of remote reprogramming.
Mica [5], released in 2001, was carefully designed to serve
as a general purpose platform for WSN research. Compared with
preceding designs, it offered more memory (4kB of RAM and 128kB
of flash), extensive sensor interfaces (8 analog lines, several digital IO

Fig. 1. Telos ultra-low power wireless module(“mote”) with IEEE 802.15.4
wireless transceiver.

channels, dedicated serial busses), and a very flexible radio interface.
Mica used the RFM TR1000 and simple modulation techniques. The
radio’s primitive interfaces allowed low power operation and quick
turn-on times. The unbuffered, bit-level radio interface connected to
several IO pins, interrupts, and an SPI bus on the main microcontroller;...