Touchscreen Using a Wii Remote

Touchscreen

Using a Wii Remote

Here’s a unique workshop on how you can convert any surface into a touch screen using a Nintendo Wii console remote.

By Francis D’Sa

Tablets and all-in-one PCs featuring a touchscreenenabled

display panel are convenient and fun to work

with. Wouldn’t you like to have a touchscreen for your

desktop or laptop too? But a touchscreen monitor would

cost a lot. Using a Wii remote (Wiimote) from the Nintendo

gaming console, you can make your regular monitor (LCD or

CRT) behave as a basic touch panel. Given below is a simple

workshop to convert almost any given surface (be it your LCD

monitor, table surface or a whiteboard along with a projector)

into a touch-enabled surface. All you would need is a Wiimote,

a simple utility available online, a Bluetooth dongle and an

infrared light source. This whole workshop has been inspired by

Johnny Lee from his website http://johnnylee.net.

Let’s Get Started

The IR pen: First, you will need to make yourself an IR

(infrared) pen. This pen is nothing but a simple IR LED powered

by a few batteries and controlled by a push/touch switch to

switch it on or off. The IR pen is required because the Wiimote

has a built-in IR camera which needs an IR light source for

detecting various points for operation. Building the IR pen is

pretty simple and can be built in a few minutes. All you need

is to figure out a way to mount the IR LED onto the tip of the

pen, power it using a battery and mount the switch. Here are

a few simple steps to build one. Remove and discard the refill

from the pen; we only need the housing. The part where the

refill’s nib exits the housing is where the IR LED needs to be

mounted. Cut, slice or do whatever needed to get the LED

fit snugly onto pen’s housing, but remember that the whole

LED should be visible on the exterior. If the LED is blocked or

covered by the pen’s housing, the IR light will not be visible for

the Wiimote to function. Once you have figured out how the

LED can be mounted, your next step is to mount the switch

and the battery. Finally, solder the wires to the switch, battery

holder and the IR LED and run the wires through the pen. Glue

everything in place after testing the pen.

How to test: Since IR light is not visible to the human eye,

you can test it by pointing the IR LED towards any camera

(video camera, digital camera, mobile phone camera or

webcam will do) and see the light glow on the display.

Have a look at the diagram for wiring ideas and a picture

of the IR pen we made. Now that the IR pen is ready, you have

completed 80 percent of the workshop. All you need now is to

connect the Wiimote to the PC, download a simple utility, and

calibrate the Wiimote with your screen.

Connecting the Wiimote to the PC: In order to connect

the Wiimote to the PC, turn on the Wiimote and the Bluetooth

hardware on your PC or laptop. Using the

pairing process of the Bluetooth, enable

the option to search for new devices

from the PC’s Bluetooth utility. On the

Wiimote, press the red ‘Sync’ button

located inside the battery compartment.

The Wiimote will then show up on your

Bluetooth utility as a game controller.

Select to pair the two without any pass

code. Let the operating system install

the necessary drivers on its own.

WIImote placement: Placement

of the Wiimote is very crucial for this

workshop to function. The Wiimote

should be able to see or identify the

glowing tip of the IR pen at all times.

For this, the Wiimote should be facing

the screen at all times. Basically, for the

Wiimote to identify the whole surface

and use it as a touchscreen, a 90-degree

angle (the Wiimote facing directly to the

screen) is the best option. But this is not

always possible as when using the pen,

you will tend to get in between the IR

pen and the Wiimote camera. This will

block the view for the Wiimote and not

work properly. Hence, you can place the

Wiimote at an angle of 45-degrees on

the left or top of the screen area. These

are the best angles if you are a righthanded

person. To place the Wiimote

on the left or top of the screen, you can

use a tripod stand and secure it in place

with a few rubber bands, or simply place

it at a proper angle on a flat and sturdy

surface. We have made a custom stand

using a dead Microsoft webcam’s mount

assembly (see image).

Note: Once you have placed the Wiimote

in a particular position, you should not

move it at all. If you do, you will need to

recalibrate the Wiimote all over again.

Calibrating the Wii mote: In

order to get this workshop working,

you'll need to download the simple

utility which basically is the Wiimote

driver and calibration tool. Once your

Wiimote is paired with your PC and

placed at the required angle, run the

‘WiimoteWhiteboard’ utility. If the

pairing of the Wiimote is functional, the

utility will run and a window with some

information about the Wiimote battery

status and tracking utilization will be

visible. Options for cursor control (to

enable or disable the Wiimote cursor),

a cursor smoothing slider (to smoothen

the cursor movement on the screen) and

a calibration button are available. The

next step is to click on the ‘Calibrate

Location (Wiimote A)’ button to start the

calibration process. You can also start

the calibration by pressing the ‘A’ button

on the Wiimote at this point or at any

time when using the IR pen to recalibrate

the points. However, we recommend

not using the button on the Wiimote as

this can tend to move the Wiimote from

its position. After clicking the button,

the screen will turn white and you will

notice a circle with a cross on the top

left corner. This circle is the beginning

of the calibration process. Using the IR

pen, touch the circle on the screen and

press the button (only once) on the pen.

The IR LED will illuminate and send a

signal to the Wiimote to detect the top

left corner of the screen. If the detection

is successful, you will see the circle

disappear and then move to the top right

corner. Continue with the same method

till you finish all four corners.

Note: if you accidentally click twice,

the circles will jump across and your

touchscreen will not be calibrated

properly. If this happens, you can simply

run the calibration once again.

After the calibration is done, the white

screen will disappear. Now minimize the

calibration utility and start using your

monitor as a touchscreen. The button

on the IR pen will act as the left-click of

the mouse. The mouse cursor will not

be visible during usage. A little practice

will help you learn the entire usability of

the interface. You can place the Wiimote

at different angles (at times even lower

than the 45-degree angle) to suit the

best possible position according to

your preference. The angle completely

depends upon the screen area, which

should be visible to the Wiimote at all

times. A very steep angle can cause

calibration errors.

Since you will be using the IR pen on

the surface of the LCD monitor, you run

the risk of scratching the surface of your

LCD screen. To overcome this, you can

use a screen guard over the LCD panel.

Since a screen guard of this size would

be very expensive, you can also use the

screen protector (the plastic sheet) that

came with monitor packaging to cover

the screen area. Alternatively, you can

use a transparency sheet that is large

enough to cover the screen area.

This workshop is best applicable

for whiteboard presentations and

handwriting inputs wherever necessary.

The utility is still under development and

will evolve and improve over time. You

can log on to Johnny Lee's website for

more details.

What you would need for this project

 A Nintendo Wiimote: You can use your existing console’s remote or

buy one from eBay for just around Rs 1,000.

A Bluetooth USB dongle: If your laptop or desktop doesn't feature

built-in Bluetooth, you can pick one up for as little as Rs 120.

An IR LED: This item can be sourced from your local electronics store

or can be ripped from any old or non-working IR remote controller

(TV, audio player, etc)

A push or touch switch: This switch can be ripped out from an old PC

case (the reset switch) or any non-working gadget which has a push

switch (for example, the volume control, power or reset switch).

A ball-point pen: Preferably a basic plastic-based pen as drilling

holes, making cuts or using super glue is easier with plastic.

Some really thin wires: Any wire thin enough to pass through the

pen’s housing should suffice.

Mercury batteries (button-sized): You can either use a regular

motherboard CMOS battery (3.2 V) or three watch cells (1.2 V each).

Ideally, we require around 3 to 4.5 volts to power up the IR LED of

the IR pen. The tiniest batteries would be ideal as they can be easily

housed inside the cap at the rear end of the pen.

Battery holder: The holder would depend on the battery type. In our

case, we ripped out the CMOS battery and its holder from a dead

motherboard.

Tools: This would involve standard tools such as a knife, soldering

iron, solder wire, super glue, electrical tape, etc.

WiimoteWhiteboard utility: This utility can be downloaded for free

from ‘http://johnnylee.net/projects/wii/WiimoteWhiteboardv03.zip’.

It is used for calibrating the Wiimote for the touchscreen and for the

entire working.