iiBOARD

Development of a Low-Cost Interactive Whiteboard using the Wiimote Controller

Marco Silva

, Luís Paulo Reis

, Armando Sousa

, Brígida Mónica Faria

and A. Pedro Costa

FEUP/DEEC - Faculdade de Engenharia da Universidade do Porto, Dep. Engenharia Electrotécnica e de Computadores

LIACC – Laboratório de Inteligência Artificial e Ciência de Computadores da Universidade do Porto

Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal

FEUP/DEI - Faculdade de Engenharia da Universidade do Porto, Dep. Engenharia Informática

LIACC – Laboratório de Inteligência Artificial e Ciência de Computadores da Universidade do Porto

Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal

FEUP/DEEC - Faculdade de Engenharia da Universidade do Porto, Dep. Engenharia Electrotécnica e de Computadores

ISR-P – Instituto de Sistemas e Robótica do Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal

IPP/ESTSP – Instituto Politécnico do Porto, Escola Superior de Tecnologia da Saúde do Porto

Rua Valente Perfeito, 322,4400-330, V.N.Gaia, Portugal

UA/CIDTFF - Universidade de Aveiro, Dep. Didáctica e Tecnologia Educativa

Centro de Investigação Didáctica e Tecnologia na Formação de Formadores

Campus de Santiago, 3800-193 Aveiro, Portugal

Keywords: Human-Computer Interface, Interactive Whiteboard, WIIMote, WII Console, Infrared Camera.

Abstract: Interactive whiteboards are gaining importance in our society, both at a business level and, especially, at an

educational level. However, the products offered by the major manufacturers have a major barrier to their

acquisition: very high prices. There is an urgent need to use new technologies in order to provide solutions

that present the same performance levels than typical interactive whiteboards, but with a significantly

reduced cost. Throughout this paper the steps taken for the development of an innovative low-cost

interactive whiteboard are described. The proposed system is based on the Wii Remote command of the

Nintendo Wii video-game console. This command, although very inexpensive has an infrared camera, and

supports Bluetooth communication. The system control is based on a wireless device, based on infrared

emitters, which supports most of the mouse events. A complete whiteboard application was also developed

using Borland Delphi for Windows. This application may be used with either one or two Wiimotes and has

a very simple and efficient calibration method. The application also includes viewing capabilities of some of

the Wiimote characteristics, as well as a flexible Notebook to increase its range of possible uses. The results

obtained through a survey conducted to a small set of whiteboard users were very positive indicators about

the acceptance of the inexpensive solution proposed.

1 INTRODUCTION

The work described in this paper refers to the design

and implementation of an interactive whiteboard.

This type of equipment has gained increasing

importance in our society in the last few years. From

the business world to personal uses, through the

education system, the interactive whiteboards are

gaining a growing market in recent years. Today,

many solutions already exist in what concerns

interactive whiteboards. However, they still have

very high prices, corresponding to a large

investment that not everyone is willing to do. There

is an urgent need to find a solution that at least

maintains the same performance levels currently

proposed by commercial applications but making

them accessible by a more reasonable price.

Recently, some applications have emerged, that

can offer a relatively similar effect to that offered by

traditional interactive whiteboards, but are based on

devices with a much more moderate cost. One of

these applications is an interactive whiteboard based

on a pen with an infrared emitter used together with

the Wii Remote, command of the Nintendo Wii

console developed by Johnny Chung Lee (Johnny

Lee, 2008). The application has been widely

337

Silva M., Reis L., Sousa A., Faria B. and Costa A.

iiBOARD - Development of a Low-Cost Interactive Whiteboard using the Wiimote Controller.

DOI: 10.5220/0001806603370344

In Proceedings of the Fourth International Conference on Computer Graphics Theory and Applications (VISIGRAPP 2009), page

ISBN: 978-989-8111-67-8

disseminated on the Internet. However it still has

some major limitations, because it only emulates the

movement of the mouse together with the

corresponding action of the left click. However,

behind this application is a very interesting idea,

which may result in a well crafted application that

allows emulate the events of the mouse almost

entirely, and also contain some features offered by

the software usually provided in the purchase of a

more traditional interactive whiteboard, as a

notebook application, virtual keyboard, etc.

The objective of this work is to study the

operation of interactive whiteboards in general and

the Wii Remote controller and to design and

implement an interactive whiteboard based on the

use of that device together with infrared emitters.

This section is a brief introduction to the work

done, and the remaining sections of this paper are

described below. In section 2 a short overview about

what is currently offered in the interactive

whiteboards market is presented. Emphasis is given

to the technologies used and the prices of the final

product. Section 3 presents the Wiimote and its

characteristics as well as the protocol used for

sending and receiving information, especially

regarding the infrared camera. Section 4 states the

decisions taken in the draft of the control device for

the interactive whiteboard developed and illustrates

its final appearance. Section 5 deals with the design

and implementation of the computer application

developed. The calibration method and features of

the application are explained. The same section

presents the results obtained in a precision test and

accuracy of the calibration model. Finally some

results are analyzed by a statistical study carried out

from a survey having in mind examining the

acceptance of the interactive whiteboard developed.

The last section contains the general conclusions of

this work and some prospects for future

developments.

2 INTERACTIVE

WHITEBOARDS

An interactive whiteboard is a touch-sensitive board

which is connected to a computer and a digital

projector which projects images from the computer

screen onto the boards.

The interactive whiteboards in the market can

make use of different technologies to perform its

tasks. The type of projection may use three different

types: front, rear or the use of a flat panel. The

interactive whiteboards with front projection are

cheaper than those of rear projection, but have some

disadvantages, such as shadows caused by the

presence of the user in front of the board and the fact

that if the user is speaking to an audience be dazzled

by the projection. These boards usually do not bring

projector included. There have however appeared

interactive whiteboards using front projection with

projector included. It is placed on top of the board,

with an angle of projection about 45°, which almost

completely cancels the situations of shadows and

dazzle of the user. Obviously these boards have a

higher price. Boards of rear projection, usually, have

already incorporated the projector and the projection

is made on the back of the board, then there are not

the problems described above. However their main

drawbacks are an increased price and a larger

volume and therefore cannot be fixed to a wall,

unless the exception of being embedded in it. In the

use of a flat panel, there is no projection and the

technologies used are more limited, generally those

of infrared and/or ultrasound. The most common

technologies are resistive, capacitive,

electromagnetic, infrared and ultrasonic.

Interactive whiteboards are present in several

aspects of our society. Already at the beginning of

the 90’s they were used in business. More recently

there has been a great interest in education to insert

the interactive whiteboards on teaching methods. A

study dated of 2007 held in the UK (Kitchen, 2007)

indicates that the interactive whiteboards are used in

almost all schools, specifically in 98% of secondary

schools and 100% of primary schools in that

European region. In Portugal this implementation is

a little delayed, but this process is included in the

Technology Plan for Education from the Portuguese

Government (Ministério Educação, 2007). Some

manufacturers also create models of its interactive

whiteboards directly targeted at government and

military areas.

Almost all the interactive whiteboards need a

manual calibration, which usually is the selection of

nine points in the interactive area. Table 1 present

five models of some major manufacturers, such as

SMART Technologies (2006, 2008), InterWrite

(2008), Promethan (2008) and eBeam (2008). In this

table the main features as well as the price are

presented (Wedgwood, 2008).

In a study from Becta (2005), it is mentioned the

fact that students are motivated and learning is

enhanced during the early stages of the use of the

technology. The same study claims that if the

computer is an increasingly part of the everyday

armoury and ICT is regarded as a key skill

underpinning all subject areas. But use interactive

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338

Table 1: Comparison of features of five interactive whiteboards.

Model Wireless Taking notes Writing Recognition Projection Projector included Price

eBeam Integral 65 No Yes No Front No 790€

InterWrite 1071 Yes Yes Yes Front No 1142€

Activboard 95 studio Yes Yes Yes Front No 1890€

SMARTBoard ESP680-N Yes Yes Yes Front Yes 3390€

SMARTBoard 2000i Yes Yes Yes Rear Yes 7090€

whiteboards have positive aspects (Miller and

Glover, 2006; Smith et. al, 2006; Becta, 2005;

Cuthell, 2005) such as:

 Facilitate collaboration with colleagues and co-

workers;

 The visual information is more easily shared,

by using drawings that the class may visualize

together.

 The most widely claimed advantage is that it

motivates students because they enjoy

interacting physically with the board,

manipulating text and images, thereby

providing more opportunities for interaction

and discussion.

 Pedagogical advantages are also noticed such as

improved planning and preparation, marking

and assessment, storing and editing lessons,

teaching style, awareness of learning styles,

planning for cognitive development, clear

visual representation of concepts, activities

that encourage an active thinking approach.

 Engagement: Motivation, Credibility and

validity and Classroom focus.

 Socio-cultural aspects: Social interaction and

working together

 Technology: drag-and-drop, hide-and-reveal,

matching and using movement.

Further educational studies emphasise social

activities focused around the Interactive Whiteboard

as fundamental to subsequent knowledge transfer

(Convery et. al, 2006). The problem is not use the

interactive whiteboards, but the ways it is used.

The main problem with the interactive boards is

still its cost that prevents its general use. The

solution presented in the next sections intends to

help solving this problem in a very simple way.

3 WIIMOTE CONTROLLER

The Wii Remote is the command of the Nintendo

Wii, and is more commonly called a Wiimote. The

Wiimote can be connected to any computer via

Bluetooth as an ordinary cell phone. The decoding of

the Wiimote protocol requires much reverse

engineering (Wiibreew, 2008) and is still not

complete, and it is not yet possible to take complete

control of all its components. Among other features,

the command incorporates an infrared sensor, and

returns the data resulting from its reading as a frame

of 16 bytes. The command may take different types

of reports. The one we are interested in this project

is the 0x33 and is illustrated in Figure 1.

Figure 1: Data received at the 0x33 mode

The bytes BB contain information of the status of

the buttons, the AA bytes contain information about

the accelerometer and bytes II contain information

on the infrared camera.

The infrared camera, when properly initialized,

returns information up to four infrared points

hypothetically visible. As it can be seen in the figure

illustrated above, 12 bytes of information are

received from the camera. So we are 3 bytes per

infrared point. In Figure 2 is illustrated the

codification of the X and Y coordinates and the size

of each point in their 3 bytes.

As it is visible, it is relatively easily obtained in

the computer the coordinates of the infrared sensor

up to four points visible in space. The angles of

vision, horizontal and vertical, of the infrared

camera of the Wiimote are 42.8° and 31.2°,

respectively. These data was collected by carrying

out a test at various distances, which were 1, 2

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339

Figure 2: Codification of data from the infrared camera on

extended mode.

and 3 meters. Another feature that was duly noted

was the frequency of receipt of reports that was

around 100Hz. So it was cleared for 20 seconds the

number of reports received every second, and that

number was always around 100 reports per second.

4 CONTROL DEVICE

The control device is the element of the system that

allows the control of the interactive whiteboard. It

allows the emulation of the events of the mouse left

button and the right click. It has two infrared leds,

which may take different orientations in case of use

of two Wiimotes very far away from each other and

that the surface of interactive area is not reflective. If

the surface is reflective the infrared leds may take

the same orientation in order to increase the potency

of the signal. The device can operate in two modes,

the calibration mode or continuous operation mode.

In calibration mode, the infrared leds are turned on

when the left button is pressed. In continuous mode

the leds are turned on, by default, and linked to the

state of left and right buttons, the events are sent

when requested. A green led have a similar

behaviour then the infrared leds to give some

feedback to the use of their state. It was chosen to

base the construction of the control device using a

four AA batteries case, illustrated in Figure 3.

Figure 3: Support for four AA batteries.

The leds chosen to implement the control system

are high-brightness and small beam angle. Table 2

(RS – HIRL5020, 2008) is present the main features

of the led HIRL5020.

The generator of control signals chose is the

AtTiny85V, an 8-pin microcontroller from Atmel.

Table 3 (Atmel, 2008) presents the AtTiny85V main

features, including its unit price.

Table 2: Main features of HIRL5020.

Half intensity angle ±17°

Radian intensity 60mW/sr

Peak emission wavelength 940nm

Spectral bandwidth 50nm

Led diameter 5mm

Forward voltage 1.45V

Forward current 100mA

Power dissipation 170mW

Unit price 0.40€

The maximum current allowed by pin is below

the current drawn by the infrared emitters, which

will take some additional hardware that allows check

their state.

Table 3: Features of AtTiny85V microcontroller.

Number of timers 2

Number of bits of processor 8

Clock frequency 8MHz

Data memory (SRAM) 512 bytes

Program memory (FLASH) 8 Kbytes

Number of inputs / outputs 6

Number of pins 8

Output DC current per pin 40mA

Input DC current per pin 40mA

Operating voltage 1.8V – 5.5V

Unit price 1.95€

The power supply for the device is provided by

three AA batteries, and the vacancy left by a

possible fourth battery is completed by the printed

circuit board.

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340

4.1 Transmission of Mouse Events

In order to send the events generated by the mouse

buttons on the control device by a single led, it was

created a protocol for sending this data. The infrared

leds are, by default, turned on so the beginning of

the data is sent by a shutdown of them. Each event is

encrypted in 8 bits, with each bit corresponds to the

state of the led during spaces of 30ms. The events

implemented are described below and their frame of

coding are presented in Figure 4.

1. Left Button Pressed: This event is relative to a

pressure on the left button during 360ms.

2. Left Button Released: This event is relative to

the act of release the left button while he was

previously pressed and that his state is no

longer changed in 360ms following.

3. Left Click: This event is relative to a left click

on the control device, made in a maximum

range of 360ms.

4. Double Left Click: This event is relative to a

double click of the left button, made in a

maximum range of 360ms.

5. Right Click: This event is relative to a right

click on the control device.

Figure 4: Telegrams of the events implemented.

As shown, the telegrams are all quite different,

which prevents the execution of events undesirables

because of erroneous readings. Otherwise, sending a

significant number of bits in a relatively short period

of time prevents that the dazzle of the infrared leds

is wrongly interpreted as an event.

4.2 Implementation

The solution to control the infrared leds is to use a

Darlington transistor to have a sufficient gain of

current to the concrete situation. To view the current

level of supply voltage, it was made a sequence of

diodes and leds to view three possible states, like in

Figure 5, while they were the batteries are full, used

batteries and dead batteries. The circuit is powered

when a push-button is pressed, in order to reduce

consumption caused by this section of the control

device. The leds are red, yellow and green. The

green led is turned off to tensions below 4V and the

same applies to the yellow led to tensions below

3.3V, for which only the red led lights, then

suggesting the exchange of batteries.

Figure 5: Circuit for viewing of the batteries state.

In Figure 6 it is illustrated the final aspect of the

control device and its components.

Figure 6: Final control device and its components.

5 APPLICATIONS DEVELOPED

The application was developed in Delphi 7.0 and can

work with one or two Wiimotes at the same time.

The application includes a method of calibration

simple and efficient, receiving the events sent by the

control device and some extra features.

5.1 Calibration

In order to place the mouse cursor in the correct

position, it is necessary to transform the coordinates

provided by the Wiimote in coordinates of the

desktop of the computer. With the formulas (1) and

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Development of a Low-Cost Interactive Whiteboard using the Wiimote Controller

341

(2) it is possible to obtain the coordinates of a point

in a 2D plan, from the viewpoint from another 2D

plan.

111

+×+×

ybxa

cybxa

(1)

222

+×+×

ybxa

cybxa

(2)

During the calibration process it is requested to

the user the selection of four consecutive points

from the desktop such as illustrated in Figure 7.

Figure 7: The four calibration points.

With the X and Y coordinates of the four points

given by the Wiimote and knowing its location Xs

and Ys on the screen, and then we may get eight

equations with eight unknowns. Calculating then the

value of the unknown values a1, a2, a3, b1, b2, b3,

c1 and c2 get a model that relates the X and Y

coordinates given by the Wiimote infrared sensor

with the coordinates Xs and Ys where we must put

the mouse cursor.

It was made a test of the quality of calibration,

using one or two Wiimotes with different positions

and with two different types of leds, where the

maximum average error for the precision was 0.49%

and the maximum average error for accuracy was

0.38%, these values perfectly acceptable.

5.2 Reading the Mouse Events

To read the telegrams sent by the control device, it

was used the multimedia timer of Windows, because

the default timer of Delphi does not work well for

intervals of less than 1s. The process is that when the

infrared leds are turned off, the timer is launched

with an interval of 15ms. In the first interruption, the

interval is changed to 30ms and it is reading the state

of the leds. In the seven followed interruptions is

repeated the reading of the leds state, thus filling a

frame of 8 bits, as in Figure 8.

Figure 8: Reading of the 8 bits of a telegram.

Once the telegram filled it is compared to know

events, and if there is a match the respective event is

processed.

5.3 Features

The aspect of the application is illustrated in Figure

9, with one or two Wiimotes connected.

Figure 9: Application using one or two Wiimotes.

Different information is given about the state of

the Wiimote(s) as well as the calibration status. The

application contains a menu with shortcuts to

applications such as virtual keyboard, paint or

notepad, among others.

Figure 10: Example of use of the implemented Notebook.

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It was developed a notebook application that

allows taking notes on the desktop, with some tools

like a colour pen, shapes and an eraser. It is possible

to save the notes in the form of an image. In Figure

10 it is illustrated an example of use of the

implemented Notebook.

5.4 Survey Results

To analyze and evaluate the preference on the low

cost interactive whiteboard project using wii

controller a survey was conducted. The survey was

made to 21 people that after testing the solution with

complete freedom, managed to respond a

questionnaire. The methodology practiced followed

the general steps of research based on survey (Hill &

Hill, 2005), starting with the definition of the

objectives of the investigation, planning and doing a

general design of it.

The population on this study was formed by

users with good skills in Informatics and Computer

Science and the convenience and probabilistic

sample had 21 individuals that work in Portuguese

territory.

Some interesting conclusions were found after

analyzing the answers. The majority of the user

inquired (81%) considered the price of general

interactive whiteboards too high. On the other hand

95% stated that the quality/price relation of the new

solution (interactive whiteboard project using Wii

controller) was “Good” or “Very Good”. Finally in

the event of needing to acquire a whiteboard, over

90% of the inquired users prefered the presented

low-cost solution.

This work was complemented by analyzing two

kinds of situations for compare proportions. First,

one in two independent samples compares users with

and without experience on interactive whiteboard

and the second one was intended verifying opinions

before and after having experience with the

interactive whiteboard with the wii controller. To

test if there were statistical evidences to claim that

the kind of answers differed with the kind of user it

was applied the Fisher´s Test. For the knowledge

differences on the level of answers among users it

was applied the Mann-Whitney Test.

In fact for a level of significance of 0.05 it

wasn’t possible to affirm that the variables

experience with classical interactive whiteboards

and preference of the IIBoard solution are associated

(p_value ≈ 1,000) and there were statistical

evidences to claim that both groups prefer the low

cost whiteboard solution.

In conclusion, the results clarify that the low cost

interactive whiteboard project using Wii Controller

had good acceptance and could be an alternative

solution for the very expensive whiteboards

available on the market.

6 CONCLUSIONS AND FUTURE

WORK

In this paper the design and implementation of a

low-cost interactive whiteboard, based on the

Wiimote was presented. The most relevant aspects

concerning the practical application developed are:

• Construction of a control device that allows to

emulate almost all mouse events;

• Implementation of a calibration method of the

interactive whiteboard simple and efficient,

whose precision and accuracy have been

properly proved;

• Flexible application, which can be executed

with one or two Wiimotes, so as to reduce

cases of occlusion of the infrared emitters;

• Implementation of a Notebook application in

order to increase the usefulness of the main

application.

The IIBoard system developed is a prototype of a

very low cost interactive whiteboard, having

however the main features of such frameworks. The

preferences shown therefore by the users of IIBoard

enable us to conclude that it would not be difficult to

transform the prototype into a commercial solution.

There are several improvements that this project

could still suffer. The main ones are:

• Transmission of the events via Bluetooth, to

make its execution in almost real time and

limit the event losses, which would also

implement the events of the mouse entirety,

including scroll;

• Implementation of a Kalman Filter to

merge the information of two Wiimotes and

to estimate the position of the cursor when

occlusion of the infrared leds occurs;

• Development of a feature for the

conversion of written to digital text, subject

to a calibration of different writing for each

user. It could also use a dictionary that

would give suggestions according to the

letters that were already written;

• Implementation of the ability to use two

Wiimotes to further extend the board

interactive area. The board would have two

halves, each of them monitored by a

different Wiimote.

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Development of a Low-Cost Interactive Whiteboard using the Wiimote Controller

343

ACKNOWLEDGEMENTS

The authors which to acknowledge to LIACC –

Artificial Intelligence and Computer Science

Laboratory from the University of Porto for the

conditions to develop this work.

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