I was fairly gobsmacked when I came across Johnny Chung Lee’s video of how to create an Interactive Whiteboard using a Nintendo WiiMote and infra-red light pen. It came courtesy of a blog post by Mr Platts (inexplicably down at the time of writing – cached version here). The video by Johnny, a PhD student at Carnegie Mellon University, is here:

Suitably inspired, I went promptly to HMV after school and bought a Nintendo WiiMote. You can get these pretty much anywhere – mine cost £32.99 but you can find them cheaper.

The other thing you need is an infra-red lightpen. These do exist commercially, but I couldn’t find one a) cheap enough, and b) readily available in small enough quantities (i.e. no minimum order). So I decided to make my own. It’s a basic circuit: all you need is an infra-red LED, a small switch, and a battery. I got mine from Maplin Electronics:

• High-power Infra-red Emitting Diode (YH70 – £0.79)
• 1xAAA Battery Box (JY45 – £0.43)
• 7/0.2 Wire 10M Red (BL07 – £1.69)
• Microswitch (GW67 – £1.29) (I chose this because of its size – you don’t actually need 3 poles on your microswitch, but if you do just solder wires to middle and one of outside poles)

I also bought a 30W soldering iron for £2.99, some AAA batteries, and some solder wire but obviously you don’t need these if you’ve already got them!

To make my IR pen easy to hold and on the eye, I decided to take apart a standard Berol DryWipe marker pen used on standard whiteboards. I’m no DIY expert, yet found it easy to take the pen apart and remove the necessary sections with a hacksaw. If I’d had a Dremel, it would have been even easier!

The finished pictures of the finished pen and the circuit it contains can be found in this Flickr set and also below:
Created with Admarket’s flickrSLiDR.

Finally, you can use the WiiMote/IR light pen combo for pretty much anything. The following video shows me turning my standard Macbook screen into a ‘touchscreen’. I’m using the WiiMote Whiteboard software under Mac OSX Leopard, but there is a Windows version too…

You may find the del.icio.us links I’ve collected along the way with the tag wiimote handy!