How to: Convert any surface into a touchscreen with a Wiimote

Tablets and all-in-one PCs featuring a touchscreen-enabled display are convenient and fun to work with. But a touchscreen monitor isn’t quite affordable for most just yet. Using a Wii remote (Wiimote) from Nintendo’s 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 (or wall) along with a projector) into a touch-enabled surface. All you would need is a Wiimote, a simple utility from the internet, a Bluetooth dongle and an infrared light source. This whole workshop has been inspired by Johnny Lee from his website ‘http://johnnylee.net’.

The Nintendo Wiimote can be purchased separately

What you would need for this project:  

 - A Nintendo Wiimote: You can use your existing console’s remote or buy one from eBay for about Rs. 1,000. You might also consider   borrowing one from a friend to test this out first.

- A Bluetooth USB dongle: Unless your laptop or desktop features built-in Bluetooth, you can pick up one of these for as little as Rs. 120. 
- An IR LED: This item can be bought from your local electronics store or can be ripped from any old or non-working IR remote controller you  might have laying around.
 - A push or touch switch: This switch can be ripped from an old PC case (the reset switch) or any non-working gadget which has a push switch   for example the volume control, power, reset button etc.
- A ball-point pen: Preferably a basic plastic-based pen - drilling holes, making cuts or using super glue is easier on plastic.
- Some really thin wires: Any wire slim 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,  you require around 3 volts – 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 holder from a dead  motherboard.
- Tools: This would involve standard tools such as knife, soldering iron, solder wire, super glue, electricians tape, etc.

- WiimoteWhiteboard utility: This utility can be downloaded for free from here. The utility is used for calibrating the Wiimote for the touchscreen  and for the entire working of this project.

Let’s get started -
The IR pen:
First, you will need to make yourself an IR (infrared) pen. This pen is nothing more than an 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.

We made this IR pen using a basic plastic pen and mounted the battery and holder from an old dead motherboard

Building the IR pen is pretty simple will take just a few minutes. All you need is to figure out a way to mount the IR LED onto the tip of the pen and power it using a battery and mount the switch. To build one, here are a few simple steps -

Remove and discard the refill from the pen—we need just 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 is needed to get the LED to 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.

Since IR light is invisible, you can test it by pointing the IR LED towards any available camera (video camera, digital camera, mobile camera or webcam), pressing a button and you should see the LED glow via the viewfinder.

Have a look at the diagram for the wiring idea 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.

The circuitry for the IR Pen is shown here. If you are not confident with soldering, we suggest you take help from a friend