Intially, I thought the sensor bar is a sophisticated piece of hardware that acts as the receiver of signals emitted from the Wii-mote and transmitts these signals into the Wii-console for processing. In that case, one would need to hack the Wii-console in order to pull motion tracking information from the device. Later, I realized that this is far from the truth. In fact, it’s the exact opposite – the sensor bar is actually the emitter of signals, and it is the wii-mote that is doing all the magic! For more information about the inner workings of Wii, check out the “Wii: Demythified” section.
To recreate the sensor bar, all you need is the following: two IR-LEDs, some wires, and a battery (can be any battery from 1.5V to 9V, although for larger batteries, you will need some resistors). Follow the following schematic diagram to build your sensor bar.
To save soldering, I used a piece of bread-board for connecting the components together. For durability, stability and asthetics, you should do the soldering and preferably mount it on a nice looking case, but that’s all optional. Here is what my final product look like:
I plan to make a video to show you how this is done. Stay tuned.
Update: I actually found a pretty good video on YouTube that teaches you how to do what I explained above to create a sensor bar (without wires) for the Wii itself.
[youtube hdxJt9UNqxE Sensor bar explanation]
Despite our sensor bar is extremely simple as a piece of hardware, we still need to test it to make sure we have connected or soldered everything correctly. If the IR LEDS are actually visible, this test would have been very simple – connect the battery and see if the lights would actually turn on. Unfortunately, IR lights are not visible to the human eyes. However, they are visible through a webcam. Connect a webcam to your PC and record a video of the sensor as we plug in and then the battery. If everything’s working, we should see the lights come up and then off through the view of the webcam.