USB Wii Sensor Bar


Ok, so any search for "Wii wireless sensor bar hack" returns a number of links to the 9V IR bar, or one of several future 3rd-party products. However, after seeing the GlovePIE script for the IR capabilities of the Wiimote, I wanted to build a sensor bar that I could use with my laptop. And since I have plenty of USB ports, I figured why would I want that bulky 9V PCB sensor bar?

Gathering the Parts

I absolutely needed to do some research on this project first. Having checked Google for info about USB specifications, how to wire LED's, and determining the best course of action, I headed out to Radio Shack for some parts. First up I needed 4 of the High Output Infrared LED's, part # 276-143. I also needed something to hold them in place, so I got a 5-pack of the LED snap-in holders. The total for those parts was about $9. I already had a USB cable that I planned to cut apart, so no costs there. But I did need to go to Home Depot to pick up something to use as a casing. I ended up getting a small 3/4" PEX pipe from the plumbing section (this pipe seemed lighter than PVC)--so $3 there.

Research and Information

Just to note, I have quite a bit of knowledge of DC wiring, and can do anything so long as it doesn't require resistors, capacitors, or other components. And since I wasn't entirely sure of how to build this circuit, I needed to get some info before I started soldering bits together. First up, an LED has two terminals, a cathode (-) and an anode (+). The cathode is usually the shorter side, and is on the side of the LED with a flat edge (on the little neck around its base). For wiring this circuit, you'd want to connect the red wire (+5VDC) from the USB cable to the anode (A) of the first LED, and the black wire (-5VDC) to the cathode of the last LED. In between you'll connect the LED's in series: positive wire to anode of LED1, cathode of LED1 to anode of LED2, and so on (ending with cathode of LED4 to negative wire).

This is a simple diagram of the circuit in plain text: (+5VDC)--(A-C)--(A-C)--(A-C)--(A-C)--(-5VDC)

And here's the same in a more graphic form:

Putting it Together

First I cut up my USB cable and got a voltage reading off my USB ports--everything was correct according to the standard USB specs (good thing, otherwise I'd be calling Dell support). So I grabbed a wall wart that could output the same voltage and amps (just in case I wired something up wrong I didn't want to fry my laptop). Next I wanted to make sure my wiring scheme would work, so I setup the circuit without soldering anything. According to most sources (circuit diagrams, resistance calculators, and notes from other modders), you should use a resistor in the circuit to make up for any extra voltage not used by the LED's. But in my case the LEDs' voltage ends up nearly matching the output from the USB port (4.8vdc), and any extra is still well within the stated limits of the LED's. So basically the circuit is extremely simple--just 4 LED's wired in series (NOT parallel). Once I knew the circuit would work, I cut the holes in the pipe to fit the LED's, spray-painted the pipe, let it dry, then inserted the LED holders. Next I placed the LED's in the holders in reverse (upside down, outside of the pipe) so that when I soldered all the connections, I knew that they would fit exactly within the holes I drilled. I then covered all the solder joints with electrical tape (just to be safe) and inserted the assembly inside the pipe. The fit was tight, but that's what I wanted. I pushed the LED's from the inside (using a long screwdriver), and carefully snapped them into the holders. I then tested the whole assembly to ensure I didn't knock anything loose--everything looked good. I then sealed up the ends of the pipe with hot glue, which also kept the USB cable in place.

The Finished Product

And as stated, the whole purpose was to be able to use the IR abilities of the Wiimote on my laptop, but without using the sensor bar from the Wii to do it. And without having to add batteries and other extra weight, this whole setup is extremely small and light (though not as compact as the real sensor bar). And best of all, I don't need to worry about extra batteries or bulk--just a small tube with a USB cable.

View the entire project album here: USB Wii Sensor Bar

The only thing I'm (obviously) not happy with is the paint job. Every time I thought the paint was dry, I ended up smudging it or scratching it off. Probably that's due to the plastic in the PEX pipe that is causing the paint to not bond well (normally I don't have problems when using PVC pipe in my projects).