How the Wii Balance Board Works

Jan. 4 2:24 PM by Alicia Ashby

So this neat video has been floating around the 'net for a few days. It's an official Japanese video that explains, more or less, how the Wii Balance Board that comes packed-in with Nintendo's Wii Fit is able to translate your movements on the board into gameplay data.

I was curious about the obviously technical information the video is meant to reveal to the viewer and got our moonspeak expert KouAidou to whip up a summary of what the video is supposed to tell us. Check it out behind the cut if you're as curious as I was, and do bear in mind this isn't a proper direct translation-- just a breakdown of the interesting parts.

This video asks the question "How does the Wii Balance Board work?"

The answer is the four sensors, one mounted in each corner of the board. They can detect your weight and the balance of your center of gravity.

The video interviews Akira Sato at Minebea Co. Ltd., the company that created the sensor. Its proper name is the Strain Gauge Force Sensor.

The Strain Gauge Force Sensor is a strip of metal with a sensor that measures force, known as a strain gauge, mounted on its surface. When force is applied to the metal from either direction, the metal will bend, stretching or compressing the foil on the strain gauge. From this, the sensor will determine the amount of force being applied.

The metal used in the Strain Gauge is duralumin, an aluminum alloy containing copper, manganese, and magnesium, which is used in airplanes.

The sensors can detect even the slightest variation in the bending of the metal that your eye wouldn't normally see. Applying 100 kg of force results in a bend of only 0.1 mm, but it can still accurately measure the bend created by a 500 gram weight.

The technology is used in bathroom scales and digital measuring devices, but also in devices to measure the weight of trucks and airplanes. It is also used in the legs of bipedal robots to allow for perfect balance.

Using this technology in the Wii Balance Board allows it to measure weight and balance accurately.