Wiimote Whiteboard IR Saber

Create an awesome IR pen from a toy light sword and control your computer with gestures.

Written by James McLain

Time Required: 1 Hour

Cost: $10–$15

Command your “smartboard” with an elegant weapon for a civilized age,

Materials

» Toy laser sword such as Amazon #B00345MQ8W. I love the style and length of this one.

» Speaker wire, 2-conductor, 24 gauge, 31"

» Resistor, 33Ω, ¼W

» LED, infrared, 940nm such as Vishay Electronics #TSAL 6400

» Electrical tape, white, 12"

» Push button, momentary

» Wire, solid

Tools

» Wire cutters/strippers

» Pliers, needlenose

» Screwdriver

» Utility knife

» Drill and or ³/₁₆" bit

» Soldering iron and solder

» Hot glue gun and glue

» Small organizer box to store parts while you work

MINORITY REPORT AND IRON MAN-TYPE INTERFACES ARE ALREADY HERE. With an easy hack, you can interact with a projection of your computer’s display just by waving a wand in midair. The setup is amazingly affordable, just needing a Wii Remote and an infrared (IR) light pen. How do you get an IR pen? You make it!

In 2007, Johnny Chung Lee invented the Wiimote whiteboard. As Lee explained in his runaway YouTube video (makezine.com/wiimotewhiteboard), every Wiimote has a high-resolution IR camera. To turn it into a mouse or an interactive whiteboard, we connect it to a computer, fix it in one place, and use movable IR pens within view of its camera.

An IR pen is a simple device — basically a flashlight with a momentary push button and a high-power IR LED like you find in TV remote controls. Most people use a dried-up dry-erase marker as the body, but performance is spotty because the LED points out the end of the pen, not straight at the Wiimote camera.

So I designed a big IR pen with the LED pointing out the side, and turned it into a small business. It’s the longest IR pen in the world!

Build Your IR Saber

1. Wire the IR LED. Split and strip both ends of the 2-conductor speaker wire. Trim the LED leads evenly and solder them to one end, taking note of which conductor goes to the positive lead, and which to negative. Insulate all connections with electrical tape or heat-shrink tubing.

2. Tear down the toy saber. Remove all screws, then take out the batteries, battery connectors, internal switch, and external button, and separate the handle shells from the “blade.”

3. Install the IR LED. Drill a hole in the side of the blade, near the tip. Cut a small flap to open up the hole, then feed the speaker wire down the hole until it emerges from the far end. Mount the IR LED in the hole with hot glue, then push the flap back down.

4. Replace the internal switch. Desolder the saber’s original toggle switch and positive battery connector (save the original string of LEDs for another project). Solder your momentary push button to the positive battery connector and the positive wire from the IR LED, wiring it in the “normally off” mode.

Depending on your saber, you might need to support your push button with a little wire bridge or hot glue so that it fits right. I also add a small gob of hot glue to extend the original external button so it will reach the new push button inside.

5. Add the resistor. Solder the 33Ω resistor between the negative battery connector (the one with the spring) and the negative wire from the IR LED.

6. Reassemble and test. Insert the batteries and close up the halves of the handle, snipping off any bits of hot glue or plastic that interfere with the new switch arrangement.

Press the button. You can’t see infrared light with the naked eye, so look at it through a digital camera, like the one in your cellphone. You should see the LED glow a bluish color in your camera!

7. Finishing touch. Neatly cover the slit in the top of the saber with white electrical tape. You can use a paper hole punch to make a hole in the tape to fit the LED.

Going Further

What can you do with your IR saber? Anything your computer can do, except bigger, better, and more badass. Create a free PC theremin, play chess or solitaire on your wall, or browse family photos and internet videos. Have a fake laser battle with your kids, teach a class, or give a presentation. You can even build two IR sabers and do multipoint whiteboard control.

I show how to set up my Smoothboard system in my videos at youtube.com/user/Shakespeare1612, and there are lots of tutorials and software online for similar “Wiimote whiteboard” setups. Enjoy!