Introduction

This is a port of Johnny Chung Lee's Whiteboard app for the actual Wii. Kudos & thanks to Johnny Lee, Team Twiizers, svpe, shagku and para.

What you need

To use this application, you need the following:

A Wii with some method to run homebrew on it, e.g. the Twilight Hack
Two Wiimotes. Wiimote 1 is for interaction, Wiimote 2 should be positioned somewhere where it can see your entire screen, but not much more. It shouldn't be moved after you have started the calibration.
An infrared Light Pen, very easily soldered according to this schematic.

How to use the application

Please see this video for an introduction:

http://www.youtube.com/watch?v=MOa3HHblfEg

What to do if something doesn't work

Use a LED with a large opening angle

IR LEDs vary in many things. One of them is their opening angle. As you can see in the video, I'm holding my pen kind of sideways. That is because my LED only has a 90° opening angle. So if I point it directly to the screen, all the light will go to the screen and none to the Wiimote. Try to get an LED with as large an opening angle as possible.

Make sure your LED gets enough voltage

Another reason can be that the Wiiimote doesn't get enough voltage. Most LEDs require 1.3V-1.5V. A rechargeable battery only outputs 1.2V! Use a "real" battery, which outputs 1.5V when full.

Due to the resistance of the wires, you will still not get the entire 1.5V to the LED. It should be enough, but if it isn't, you can use two batteries in a row. This will result in 2.4V if you use rechargeable batteries or 3V wiith regular batteries. That is too much for the LED, but it will still work for a while (especially since the LED is only on for small amounts of time).

Comment by azeazezar, May 21, 2008

A simple tv remote seems to work fine here, as long as you aim for the wiimote. Good enough for testing this program anyway.

Nice work!

Comment by bjo...@giesler.de, May 21, 2008

@azeazezar: Good idea! Probably depends on the remote's modulation rate, though; if that is too low, you'd get lots of on/off cycles when you hold down one button.