Wiimote Whiteboard Lab

Sat, 24 Jan 2009 10:37:00 -0500

Having been very intrigued by the experiments of Johnny Lee using the Nintendo Wii remote, I decided to give one of them a try. I decided the experiment that would be most useful to me was the interactive whiteboard.

Following several instructions by different people online to build an infrared LED pen, I went to Radio Shack, spent about $10, and had a (somewhat) working version after about 5 hours worth of work. Had I known what I was doing, it should have only taken me about an hour, if that.

The first problems I ran into were due to a lack of understanding of some fundamental principles of electricity. Initially, I was using a battery housing that holds 3 AAA batteries (thinking that much power was needed) end-to-end outputting 4.5 volts (1.5 volts each). Each IR LED I used to complete the circuit ended up overloaded and burned out. Finally, with some advice from my father with a background in electricity, I learned that keeping the positive and negative ends of the batteries separated (laying them side-by-side instead of end-to-end), I could increase the output without increasing the voltage. Thereby powering the IR LED without burning it out.

That hurdle overcome, I started discovering that sometimes the IR LED was getting power, and sometimes it wasn't. Had I done some more research online, I could have saved myself a couple hours. I finally learned that with LEDs, polarity matters. In other words, the positive and negative charges had to be correctly paired with the tips of the LED. So, the cathode tip of the LED must be matched up with the positive charge of the battery. After discovering this, I learned that one AAA battery provided sufficient power for the LED, which made construction of my circuit much easier.

Finally, the last major problem I had was reading. Yes, reading the packaging on wire I bought to connect the components in the circuit. Had I read the package, I would have seen that the wire I bought was covered in a protective coating. So in order for it to conduct the electricity of the circuit, I had to scrape the coating off the tips to make a good contact with the battery and LED and other components.

Back to one of my earlier statements; I had it (somewhat) working. Was my IR LED pen able to "transmit" data to my Wiimote? Yes. Was it consistent? Somewhat. Was it as easy to use as a real whiteboard? No. It was quite difficult for me to find a position for my Wiimote where it could "see" the IR beam or reflection. This led me to believe that either the IR LED I purchased wasn't providing sufficient light to be seen by the Wiimote or that something about the circuit I constructed wasn't optimal. Either way, not being knowledgeable enough about the Wiimote's capabilities, the electrical circuit I was attempting to construct, or the properties and capabilities of the IR LED with which I was working, I just wasn't getting the expected results.

I decided that for my experiment I was at least successful even if my construction was not optimal. In the end I decided to purchase an inexpensive IR LED pen online that used the same brand and model of IR LED as originally recommended by Johnny Lee (NOT available at my local Radio Shack). It worked like a charm! I also found that using the Wiimote with the IR LED pen worked the best with a projector instead of on a computer monitor.

So, if you consider yourself anything of a hobbyist with some basic electrical knowledge, you should give this a shot yourself. If you just want to see and use a virtual whiteboard with a Nintendo Wiimote and infrared LED pen, save yourself some time and frustration, and buy one online!

GenuineJD - Wii

Wiimote Whiteboard Lab