Keep on Rockin in the Wii World (Wii Whiteboard - Part 6)

Brett Favre, I understand. Looks like I had to go back on a previous decision, too. Tracking down an IR LED light source when time was a factor was not easy. So, with some help from Bryan at Radio Shack in Troy, NY, I decided that it was now or never. I was going to build one.

Supply List for the Infrared L.E.D. Device (all scored at Radio Shack)

• Lithium Ion Batter - Power Source
• Power Source Holder
• Soldering Gun
• Solder
• Wire
• IR LED Bulb
• Casing
• On/Off Switch
• Project Casing

It seemed easy enough to do. Drill two holes in the project casing, one for the push button and one for the LED. light bulb. Put the Lithium Ion battery in its casing and then, using the 20 gauge wire, solder, and the soldering pen, solder one wire from the end of the bulb to the positive battery lead. After that, solder the negative battery lead to the one of the switch leads, and then the other switch lead to the second end of the bulb.

It might sound complex, but it was actually pretty easy –and I had never soldered anything before. The only problem is that I couldn't test it until I made it work. And that is when the fun began.

It's Go Time

Realizing that GlobalSpec had put some generous funds behind me in this quest, I fired up the computer, synced the Wiimote (with dying batteries – I learned that the hard way) using the Bluetooth adapter, and opened the Wii Whiteboard program. All of the software was working perfectly with the Wiimote. Excited, I clicked the button to calibrate my infrared device, pictured above, and pointed the device at the screen. I pushed the red button, ready to have an interactive desktop…nothing. You knew it couldn't be that easy.

I took the IR device apart and checked the wires. I took out the battery and placed it right between the wires on the bulb and pointed it at the screen. It looked like I was getting something, so what was the deal? The problem was that there is a positive and negative on an LED DC powered light bulb (despite hearing otherwise from a reliable source). When I flipped the battery around, it worked. Sort of. I noticed I was getting bizarre infrared reads on calibration and eventually, after turning the computer and sensor in all different directions, realized that it had to do with the Nintendo Wii sensor that was in the room (which is really a series of infrared LED itself). Even with that eliminated, the best I could get was 17% calibration efficiency (CE). Most noted that 50% CE is very good and that it is almost impossible to have 100% CE.

Giving it a Swirl

As soon as I realized that it was working, I opened Microsoft Paint to see what I could do – which at 17% CE, was not much. Not to mention, I have horrible artistic skill to begin with.

I was enthused, though, because it worked. I could move the IR device and the mouse would follow. It was not without its problems, because it didn't track well at such a low CE, so my new goal was set: improve calibration through practice and see if moving away from another IR source didn't improve the problem.

It turns out that it did – somewhat. Even with calibration only at 8%, by backing up from the screen and with no interfering IR LED around, I was able to get much more precise control. At this point, not sure of where to go to improve any further, I called in the big guns, FrankD20 of Workbench Creations, to see if I was doing something wrong.

Next Blog: Rethinking the IR LED