Development of Wearable Device by Kid’s
Friendly Design for Kid’s Safety
SeungHee Lee1, Jahee Sohn1, Atsushi Usami2, Masatoshi Hamanaka2,12

Graduate School of Comprehensive Human Sciences, University of Tsukuba ,Graduate School of Systems and Information Engineering, University of Tsukuba
1-1-1 Tennodai,Tsukuba, Japan1{lee, jahee80}@kansei.tsukuba.ac.jp, 2{usami, hamanaka}@iit.tsukuba.ac.jp

Abstract. In this study, we develop a wearable device for kids under 6 years whoare growing up so fast physically enough to face various experiences but low abilityto describe the events by language exactly what they have experienced at nursery or
kindergartens to share with their parents. This system will be linked with local safety
network to let somebody react real time when a kid faced to any inexperienced events.
We adapt biological information such as heart rates, physical information such as
body movements, GPS and camera on the device. The data from the device could beshared to parents or teachers in the kindergarten afterwards or real time. We focus on
designing the device has fascinated form giving, ease to wear and symbolic indicationof “Protected” by wearing on. To keep kids enjoy wearing the device as like apendant. In this paper, we introduce the user oriented development of the device
which has kid’s friendly design and useful function.
Keywords: Kid’s friendly design, areal network, shared information

1.

Introduction

In increasing crimes or accidents on kids, parents need to consider the way to protect
them and predict what are going to happen to them to know their habits of ordinary
behaviors or related people around them. In Japan, it is now very general to protect
the children from the crimes, most of the primary school children put security alarmbuzzer on their school bags. Some schools hand it out to the students as like textbooks.
But many of the children do not give attention to it and no useful function except tomake noses surround. No more security functions with the alarm buzzer but a simple
toy.
In many cities, increasing working mothers’ kids are being taken care bynurseries or kindergartens on their working days. They spend less than 3-4 hours with
their kids before and after working per day. And under 6 year kids they are growing
faster in physically but sometimes cannot describe their experiences by words to theirparents even though those were scary, happy, surprise or sad.

But the responsibility of kids’ security is on their own parents wherever,whenever or whatever. In this system, we construct a system which can help theparents can confirm their kids’ behavior or experiences through a small and charm
wearable device connected to social network with local support. This device candetect heart rates and behavioral movements of kids using heart rates detector andthree axis accelerometers. It also has a camera which turns on only when the kid got a
big change of heart rates or movements such as falling down or jumping down. And
the visual information on the camera can be browsed at home through a secured
program.

2.

Development of wearable device for Kids

The device is developed by reversed order compare to ordinary development process,such as, designing first and put the advanced technology in a box next. The reason
why designing first than the technology is, to make kids wear the device as their own
willing being fascinating by attractive form giving and ease to wear. We call it, ‘Kids
Friendly Design’.
For ‘Kid’s Friendly Design’, we first concern the weight and size of thedevice, and secondly about how and where to wear on kid’s body. Concerning
preferred graphical design for kids would be the last step.
2.1 Weight and size of the device
To fix the size of the device, we surveyed Kids’ body scale based on Research
institute of Human Engineering for quality life in Japan. They’ve reported all the sizeof average body scale of ages from 0 to 12 from Japanese kids since 2005 every year.
The chest size of 3 year old kids is 164mm and 5 year is 176mm. From the chest size,
the device should not be exceeded 100mm in any direction.
About the weight, we surveyed the toys which can be attached on kid’s neck,most of them are between 30 to 50 grams and which can be attached on their waist,
are less than 100 grams. And we also surveyed about the weight to mothers in thekindergarten, 75 percent of them answered under 100 grams can be applied to theirkids. For references, the alarm buzzer has 45~60 grams and kids mobile phones have130~150 grams.
2.2 How and where to wear the device
To attach on an appropriate position on kids’ body, we should concern that it is not tobother kids’ active movements. And at the same time, the camera on the device
should be keep positioning well focused even they move around. Here we show
examples of A and B on the figure 1 and 2.
2.3

Design development of the wearable devicea.

Necklace Type
Based on example A, we suggest necklace type of ideas and mock-ups(Fig.3) .

We build up the mock-ups by 3D Printer (Dimension 3D Printer BST).
This necklace type is not able to fix the camera focused and have apossibility to be fastened on kids’ neck by accident.

Fig.1 Example A (Clip type)

Fig.3

Fig. 2 Example B (Suspender type)

Necklace Type Design

b. Shoulder Sac Type
Based on example B on the figure 2, we suggested four kinds of ideas andmock-ups (Fig. 4). This shoulder sac type is more stable to put a camera on
the device and have a diversity of positioning the sensors. Those are wellattached on the body, so children feel lighter than a real weight. B-1 could bemade with fabrics or covered with soft rubbers. It fits on the body but thecamera position could be lower than other types. A kid’s chest is high as
grownups’ knee. If the camera placed lower position on the device, we needto do to control the direction of lens. B-3 is updated idea of B-1. A support
belt was added on the other side to improve the stability. B-2 has less space
attached on the body than B-3. It has three corners on the shape and eachcorner connected with belts. And B-4 is applied idea of B-2. It has four
corners to spread sensible weight better than others. Figure 4 shows thevarious shape of device design on kids around age of 4-5 body sizes.

Fig.4Development of various shape of wearable device design

2.4
Build-in mock-ups
From the shoulder sac types of design, we finally build the sensors based on the idea
B-3. The total weight of the sensors which should be built in, would be at least 90grams, the necklace type was rejected from the candidates, because it will be a big
burden on their neck. Among four ideas of shoulder types, it offers relatively highposition of camera and merit of ease to wear.
In detail, to decide the size of device, we made updated sketch of B-3(Fig.6)
and made a 3D mock-up by 3D printer. To put the sensors safely in a box, the layout
was decided after trials. On figure 7, solving the way to fix on the body, small
connection parts were created on the corners. We named it ‘Omusbi’ (Fig.10),
meaning of ‘Rice ball’ or ‘Connection’ in Japanese. ‘Rice ball’ is traditional snack forkids and any ages of people in Japan. ‘Connection’ is also meaningful function withthis study to share information not only between kids and parents but also with local
supports.
The on-off switch is on the back side in a tiny hole to turn with an originallydesigned stick only by their parents to prevent to be adjusted by somebody else.

Fig.5

Fig.7

Built-in Device

Design Sketches for final mock-up

3.

Discussion

3.1

Weight and size of the device

Fig.6

Updated Sketch of B-3

Fig.8

Prototype of Device(Omusbi)The goal of designing the devices in this paper, less than 100 grams and 100 mm inevery direction for kids between ages of 2-6 was achieved. The model having threecorners concluded as the final design for kids in this study. We adapted the sensors,
such as heart rates detector, GPS, three axis accelerometers, camera and micro
computer in the device and we still have a possibility that it could be lighter if thesensors we adapt will be lighter and smaller. The final prototype has 94 gram with outthe belt.
3.2

Position of wearing the device

To take heart rates, kids will attach a set of wireless detectors on their left side ofchest directly. Then the device should be positioned on the right side of chest onoutside. The ‘Omusbi’ device has three corners to fix on the chest so, it does notbother to get signals each other. Figure 9 shows how kids wear the device.

Fig.9Device attached
On Kid’s bodyFig.10Omusbi

3.3Graphical package for Kid’s Friendly Design

Graphical package of device will be also very important for kids to make them want
to wear the device by themselves. It will be also a symbolic indication of “UnderProtected” when they wear the device. With friendly animal graphics or originallycreated hero characters would be preferred by kids. Figure 11 show the examples ofgraphic packages on the device.

Fig.11

4.

Graphical package examples

Future Study

This study is under going to be linked with local safety network and usability test bykids in the kindergarten will be continued in the next stage. The design of Omusbi
will be upgraded to be lighter and more fancy at anytime when the better sensors aredeveloped. For user friendly design, various types of devices will be offered toparents. They can choose the functions on and off among the sensors to depends ontheir kids’ condition. Each of them will have different experiences and different
feeling on the events around them. The device will offer scenes of kids’ dailyexperiences only when they were stimulated by unexpected events, to the network bypictures when parents access on secure system. And also staffs of kindergarten or
nursery can also access when the kids got some changes on their physical conditions.
sAcknowledgement
This study is a 	  consignment project with SCOPE (Strategic Information andCommunications R&D Promotion Program) of Ministry of Internal affairs andCommunications in Japan.

References
1. Farringdon, J., Moore, A.J., Tilbury, N.,Church, J., Biemond, P.D.: Wearable Sensor Badgeand Sensor Jacket for Context Awareness. ISWC, pp.107 (1999)
2. Kern, N., Shiele B., Junker Holger, Lukowicz P., Troster G.: Wearable sensing to annotate
meeting recordings Euro-Par 2006. LNCS, vol.7, No.5, pp. 263-274. Springer, HeidelbergLondon (2003)
3. Wiklund M.,:Usability in practice: how companies develop user-friendly products.
Academic Press Professional, Inc. (1994)