Wiimote Whiteboard Adventures

Inspired by Doug Belshaw's post over here, I was finally inspired to try and build my own wii IWB system.

I'm not the most practical person (I'm still very proud of my D+ in woodwork at school) and I have never soldered anything in my life. But undaunted by this I trecked off my local Maplins electronic store and bought a few bits and pieces, as outlined by Doug.

Namely

An infra red LED
A microswitch
An AAA battery holder
some wire
Soldering iron and wire
A small plastic box

Stupidly I forgot to buy batteries so I had to liberate one from the pile of remote controls under the coffee table.

Putting the kit together wasn't too difficult. I had never soldered before, and an electronics wizard would probably freak at my technique, but the wires are held in place firmly so no problems there. I used a dremel to cut a few holes in a plastic box I was going to use as a holder and with a copious amount of sellotape, fixed everything in place.



The first big problem is that being as how the human eye is not able to pick up infra red, there was no way for me to know if the LED was working. I just had to assume it was.



I downloaded the Wiimote software, connected the wiimote via bluetooth to my laptop and.... well.. nothing happened. I was convinced there might be a bluetooth error (its been playing up in Vista) so I installed the BlueSoleil bluetooth driver... and promptly broke my bluetooth - the only blue I got was a blue screen of death....

I then spent the next few hours trying to get bluesoleil uninstalled and my old bluetooth working again! Once fixed I decided to leave Vista alone and try it on an old XP laptop instead.

This morning I wondered if the fault lay with the LED system. In my haste yesterday I completely forgot that the D in LED stood for Diode, which meant it had to be connected in a specific kind of way (hey look, I'm a biologist, OK?). Checking the connections I found that I had connected it correctly, but more through luck than judgement.

That left the switch. There are three terminals on the switch, and I had soldered the wires to the middle one and took a guess on which end to connect it to. So I cut the switch out of the circuit and just connected the wires together.

It was then I remembered reading somewhere that some digital cameras can detect infra red light. So I tried my N95 camera and pointed it at the LED. And success! You could see that the LED had come on. So the fault lay in the way I'd connected up the switch. I can rectify that later.

I then tried to detect the LED with the wiimote and again it worked more or less OK. The only issues are

1) getting the correct angle and range for the wiimote. I didn't get the exact LED I wanted and I dont know if this is as powerful. Range is pretty limited.
2) The plastic box shields a lot of the IR from the LED... Although I have the LED poking out through a hole in the end of the case it doesn't get picked up by the wiimote too well.

I need to redesign my LED pen a little. I may take a leaf out of Dougs book and get a large drywipe pen and embed the LED in that. I also have another LED on order from Maplin mail order that hopefully will work better.

So at the moment, no cool video of me using my wiimote on the wall. Hopefully I can rig something better up when I get a chance next week and my components arrive from Maplins.

Watch this space.

Update: Another good tutorial on building an IWB wiimote lightpen can be found here: http://www.teacheronlinetraining.com/wiimote/wiimotesteps.html