Wiimote secrets explained with tiny springs

If you’re like me, then you marveled at the Wiimote as it controlled game play just by moving around in real space, and attributed it all to magic. Or pixie dust, like I also thought once upon a time about the iPod nano when it first came out. But, like I found out today, you’d be dead wrong — it’s all tiny springs!

“The technology behind motion-sensing has been around for a while, but recent technical advances have radically brought down the price — and the size. The new game controllers are the first gadgets that promise to bring the technology into the hands of millions of people, and manufacturers are now using motion sensors in other consumer products, including cell phones.

The technology is a wonder of miniaturization and precision. Here’s how Benedetto Vigna, head of the unit at Switzerland-based STMicroelectronics NV, which makes a motion-sensing chip for Nintendo, explains how it works:

When you wave around the new Nintendo controller, two tiny, flat pieces of silicon inside it, each weighing about a millionth of a gram, flex against silicon springs that hold them in place.

The movements are minute, or to put it another way, they’re on the scale of 10 to 100 hydrogen atoms stacked side by side.

But these tiny movements can be measured with incredible accuracy. A charge is applied between the moving pieces of silicon and two nearby sensors. Faint fluctuations in that charge, as small as that of 10 electrons, are picked up by a chip that translates it into an understanding of how the controller is moving.

The two moving weights, which fit together on an area less than a millimeter square, have different roles. One has two sets of springs, which allow it to move from side to side and back and forth. The other weight is a flat piece anchored almost like trampoline. It senses vertical movement. This way, the chip can distinguish motion in all three dimensions of space.”

There goes my miniature hamster wheel theory…