TouchscreenUsing a Wii Remote
By hackoooo.blogspot.in
Here’s a unique workshop on how you can convert any surface into a touch screen using a Nintendo Wii console remote.
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.
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