Special Feature

Stick-on Communicator and Its Broadband Applications—A Compact Wireless Device
with a Built-in Sensor and Actuator Connecting the Real World and the Network
Shin’ichiro Mutoh†, Fumiharu Morisawa, Jun Terada,
Yasuhiro Sato, and Yuichi Kado
Abstract
The Stick-on Communicator (StiC) is a compact wireless device with a built-in sensor and actuatorthat can be attached to any real-world object including a person. It has an adaptive sensing function thatenables control of processing parameters for sensing to be controlled via the network and a precise location-detection function using infrared light. These functions enables flexible value-added sensing services that faithfully reflect real-world situations. New broadband + ubiquitous services provided by combining real video images with information obtained from StiCs will lead to an advanced communicationstyle that enables easy and natural access to remote objects.

1. Introduction
As the broadband network continues to expand
through the introduction of ADSL (asymmetric digital subscriber line), FTTH (fiber to the home), andother types of connections, a diverse array of largecapacity, high-speed video delivery services isbecoming available. However, these services are limited to the delivery of video data in only one direc† NTT Microsystem Integration Laboratories
Atsugi-shi, 243-0198 Japan
E-mail: mutoh@aecl.ntt.co.jp

Broadband services

tion, such as the delivery of stored video content,
video from Web cameras, and live video of music
concerts. In short, the inherent bidirectional nature ofnetworks has not yet been used to advantage. Meanwhile, there has been heightened anticipation for
ubiquitous services in recent years as more attention
is placed on the customer through anytime/anywhere“context-aware” services. The aim here is to provide
optimal services for each and every person by determining and analyzing the current state, behavior, andpreferences of people and/or things via a large number of sensors connected to the network. As shown inFig. 1, the convergence of ubiquitous features with
Ubiquitous services

Sensor network
Wearable sensing
RF-ID application
Mobile computing services reflectinguser’s “presence” information

Stored-content delivery
Web camera
Live broadcasting

Large capacity, high speed

Anytime/anywhere, context-aware

New services combining broadband + ubiquitous features

Fig. 1. New-service directions.

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Special Feature

2. Stick-on communicator

Antenna

NetworkRadio circuitControl circuit

Radio circuit

The Stick-on Communicator (StiC) is a compact
wireless device with a built-in sensor and actuatorthat can be attached to any real-world object including a person. It features an adaptive sensing function,
which enables processing parameters for sensing tobe controlled via the network, and a precise-locationdetection function using infrared light. These functions enable flexible value-added sensing servicesthat faithfully reflect real-world situations. This article introduces the concept of “touching remoteobjects” by delivering information obtained by StiCs
along with real video images, which is one way thatubiquitous technologies can contribute to the promotion of broadband services. By “touching” we mean i)
obtaining sensing data that could not be obtained
from only video images and ii) interacting with actual people and things in a physical manner. The idea
here is not simply to enable remote video viewing ofactual objects located elsewhere, but to enable someone to communicate with any of them bi-directionally via a network.
The StiC acts as a network sensor and/or an actuator. As a sensor, it can obtain the current state of theobject to which it is affixed and that of the object’s
surroundings in real time. As an actuator, it enables
physical interaction with that object.

2.1 StiC configuration
Figure 2(a) shows the basic StiC configuration. A
StiC consists of a sensor or an actuator as desired, aradio circuit for communicating with other StiCs anda control circuit for controlling all operations. For
low-power consumption, it uses a 315-MHz radio
unit, which uses a lower frequency band than wirelessLANs and Bluetooth. The radio unit communicateswith access points on a TCP/IP network using a wireless-communications protocol that we developed,
and it exchanges data with personal computers andother devices on the network. A StiC therefore makes
it possible to acquire information about persons orthings to which it is attached and information about
the objects’ surroundings, and it sends the information to the network.
Figure 2(b) shows a StiC system configuration for
greater adaptability to various usage scenarios. Most
network-sensor applications to date perform somekind of sensing by a predetermined fixed operationand send the sensing results to pre-determined users.
In the coming ubiquitous era, however, we can envision the use of many sensors by many users for various purposes. In this environment, it will become
increasingly important that the sensing operation is
not fixed but is adaptive to current conditions andneeds. As shown in the figure, this StiC configuration
allows important processing parameters for sensing(e.g., amplification and sampling frequency in analog-to-digital conversion) to be set over the networkin real time. In short, StiCs make it possible to set
optimal, real-world sensing conditions in real time inaccordance with peripheral conditions and/or userneeds. This capability enables the provision of flexible sensing services that reflect the real world via thenetwork.

Control circuit

existing broadband services suggests the possibilityof “broadband + ubiquitous” services that go beyond
the conventional unidirectional video-delivery framework. Such services could provide a high level ofinteraction between the customer and service
provider and reflect the tastes and desires of individual users in a natural manner.

AcADC

Filter

VGASensor

AcADC

Filter

VGASensor

Programmable
logic circuit
SensorActuator(a) Basic configuration

SensorSensor

VGA: variable gain amplifier
Ac-ADC: adaptive-cyclic analog-to-digital converter(b) Network-adaptive configuration

Fig. 2. Stick-on Communicator configurations.

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3. Concept of a video service using StiC

manner.

3.1 System overview
This section introduces the “touching remoteobjects” system (Fig. 3) as an example of a broadband + ubiquitous service using StiCs. This systemprovides the user with the means of communicatingbidirectionally with remote objects in the real world.
First, the system detects the presence of StiCs
attached to real objects and delivers information
about those objects via the network together with areal video image. The user can simply “click” on themarker corresponding to an object of interest in thevideo image displayed on the touch panel. This simple operation displays previously registered information or real-time sensing information about thatobject, or interacts with the actuator in the StiC. In
this way, the system enables even users unfamiliar
with computer operations to interact with remoteobjects in the real world in a straightforward intuitive

3.2 Location detection function
To overlay clickable markers on objects in thevideo display, the system needs the coordinates ofeach real object in the camera’s field of vision. Thislocation-detection function is outlined in Fig. 4. The
infrared camera detects infrared light emitted fromthe StiC having the ID number of interest. Then,
using the output signal from the image sensor in thecamera, it computes the coordinates of the light-emitting point from the received-light intensity andextracts the location of the person or thing in the camera’s field of vision in real time. Some conventional
image-filtering techniques are used to suppress theinfluence of noise caused by infrared from sunlight,
remote control units, and so on.
This function can perform high-speed recognition
at a rate of about 50 IDs per second (including moving objects) and it is possible to detect the location ofInfrared (location detection)+ video camera

Check the state of real-world
objects like people and things

Simply touching a marked person or thing in the video image
displays information about that object or accesses it.

NetworkStiCs

Touch-panel display
StiC access point

Displaysinformation

Real video

Objectinformation

Vibrates StiC to
get person’s
attention“Click”
User display

ID, location, sensing value,
actuator * control

Real world* A device such as a light-emitting diode, speaker, or vibrator that provides physical interaction when an electrical signal is applied.

Fig. 3. A configuration of the “touching remote objects” system.

StiC(location-recognition section)µP

Infrared camera

Image sensor

Infraredemission(x,y)

StiC emits Infrared light.

Calculates coordinatesof light-emitting point(= location of person/thingin camera’s visual field)
from intensity

Camera captures StiC
space and detects location.

Fig. 4. Outline of the location-detection function.

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Special Feature

Stic(3) Information Display
ID:10012: Sunflowers-Artist: Vincent van Gogh
-Notes: impressionist-Description #1: born in 1853 in The
Netherlands. Died at the age of 37
leaving more than 2000 works-Description #2: “Sunflowers” is awork of van Gogh’s Arles period
during which time he lived withPaul Gauguin.

Clicking on the marker vibrates theStiC and gets the person’s attention.

Stic(3) Information Display
˚C Temperature sensor value
403020.9˚C

20
100Time

Clicking on the marker displays information.

Fig. 5. Demonstration scene.

about 100 real objects within the field of vision. Thesystem can therefore obtain detailed information
about almost all objects in a room, including anobject’s whereabouts and the history of its movement.
3.3 Demonstration example
Figure 5 shows a demonstration of the “touchingremote objects” system, where the system is delivering real video of a remote scene over the network anddisplaying that video in real time on the touch-panel
display for the user. At the remote location shown,
StiCs are attached to various objects including paintings hanging from the wall, soft-drink bottles andcans on the table, and a human being. The system displays a marker over each of those objects on the display. As shown in Fig. 6, clicking on a marker candisplay attribute information about that person orthing, provide sensing values, or trigger the actuator.
In the scene shown in Fig. 5, the user has clicked on
the marker corresponding to a painting, resulting in
the display of attribute information (a description ofthe painting). The user has also clicked on a bottle’s
get-sensing-value tag, resulting in the display of realtime temperature information. The user could also
click on the marker near the man’s shoulder to get hisattention, just like saying “excuse me” in real life.
The actuator on his StiC activates a vibrator. Thus, thesystem effectively lets you call out to a person
appearing in the video.
3.4 Potential application fields
Figure 7 shows two examples of application fields
envisioned for the StiC. Figure 7(a) shows how StiCs
could be applied to art galleries, museums, and aquariums to enable remote browsing of works in an exhib56

Display previously registered information

Other

Display real-time sensing values

Trigger actuator in real time

Fig. 6. Example of marker operation.

it and the creation of a remote study program linkedto those works. Figure 7(b) shows an example of aremote nursing/care system in which the user is able
to determine current room conditions and even operate electrical appliances in the room.
In addition, by linking an object’s attribute information with information in product tags (such asRFID tags) used for tracing and delivering that information together with video images, we envision theapplication of StiCs to advanced quality-controlprocesses. In the distribution of fresh food, for example, a user could obtain changes in storage conditions
from sensors together with a video feed in real time
while referencing product information stored in theproduct tags of that food.
4. Conclusion
StiC is a compact device that connects the realworld with the network. It features adaptive sensing
and precise-location-detection functions. It supports
the concept of new broadband + ubiquitous services
obtained by combining real video images and theNTT Technical Review

Special Feature

Adjust airconditioner
temperature

Turn offTVThis
painting
is . . .

(a) Remote art gallery

Bloodpressure
is normal.

(b) Remote nursing/care system

Fig. 7. Application examples.

information obtained from StiCs. The keys to making
StiCs practical in everyday life are a compact device
configuration and long-term operation. NTT
Microsystem Integration Laboratories will researchand develop ways of reducing StiC power consumption first by introducing low-voltage circuit technologies and power-management techniques and then by
investigating the use of natural energy sources, suchas light, heat, and vibration.

Vol. 2 No. 2 Feb. 2004

References
[1]

[2]

[3]

Y. Kado, Y. Matsuya, and T. Tsukahara, “Low-power Circuit Technology for Ultra-compact Network Appliances,” NTT TechnicalJournal, Vol. 14, No. 6, pp. 35-39, 2002 (in Japanese).
J. Terada, Y. Sato, F. Morisawa, S. Mutoh, K. Fujii, and Y. Kado, “A
Wireless Sensor-Network System with a Dynamically Programmable
Sensor Interface,” IEEE Sensors, Abst. pp. 202-203, Oct. 2003.
F. Morisawa, J. Terada, Y. Sato, S. Mutoh, and Y. Kado, “Touching
Remote Objects,” Proceedings of Interaction 2003, Japan, pp. 223224, Mar. 2003 (in Japanese).

57Special Feature

Shin’ichiro Mutoh

Yasuhiro SatoGroup Leader, Low-voltage Circuits ResearchGroup, Smart Device Laboratory, NTT
Microsystem Integration Laboratories.
He received the B.E. and M.E. degrees in electronic engineering from Chiba University, Chiba
in 1986 and 1988, respectively. He joined NTTin 1988. Since then he has been engaged in R&Dof 1-V operating logic and memory circuit technology. He received the Young Engineer Award
from the Institute of Electronics, Information andCommunication Engineers (IEICE). His current
interests are small-size ubiquitous devices suchas low-power sensor nodes and their network
applications to the sharing of real-world information on networks. He is a member of IEEE andIEICE.

Senior Research Engineer, Supervisor, Smart
Devices Laboratory, NTT Microsystem Integration Laboratories.
He received the B.S. and M.S. degrees inchemistry from the University of Tokyo, Tokyoin 1987 and 1989, respectively. In 1989, hejoined NTT LSI Laboratories, Atsugi, Japan. He
has been engaged in R&D of LSI interconnection
technology, ultra-thin-film CMOS/SOI process
and device technology, and low power communication appliances. He is a member of the Japan
Society of Applied Physics, IEICE, and IEEE.

Fumiharu Morisawa
Low-voltage Circuits Research Group, Smart
Devices Laboratory, NTT Microsystem Integration Laboratories.
He received the B.E. and M.E. degrees in computer science from Keio University, Yokohama
in 1997 and 1999, respectively. He joined NTT
Telecommunications Energy Laboratories, Atsugi, Japan in 1999. He has been engaged in R&Dof StiC and its applications. His current interests
are very low power consumption active tag systems. He is a member of the Information Processing Society of Japan (IPSJ), IEICE, andIEEE.

Jun Terada

Yuichi Kado
Executive Manager, Smart Device Laboratory,
NTT Microsystem Integration Laboratories.
He received the M.E. and Ph. D. degrees inelectronics from Tohoku University, Sendai,
Miyagi in 1983 and 1998, respectively. In 1983,
he joined NTT Electrical Communications Laboratories, where he engaged in research on SOI
structure formation by heteroepitaxial growth.
From 1989 to 1998, he worked on the development of fully-depleted CMOS/SIMOX LSIs andultralow-power CMOS circuits. From 1999, heengaged in R&D on compact network appliances
using ultralow-power CMOS circuit technologies for ubiquitous communications. He hasserved as a program committee member of theISSCC (International Solid-State Circuits Conference) since 1999 and a technical committee
member of IEEE Computer Elements since 2003.
He is a member of IEEE and IEICE.

Research Engineer, Smart Devices Laboratory,NTT Microsystem Integration Laboratories.
He received the B.E. degree in electrical engineering and M.S. degree in computer sciencefrom Keio University, Yokohama, in 1993 and1995, respectively. In 1995, he joined NTT LSILaboratories to study analog LSIs, especially
A/D and D/A converters. Since 1999 he has been
researching a system for achieving ubiquitousservices in NTT Microsystem Integration Laboratories. He is a member of IEEE and IPSJ.

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