Have you ever wondered how your iPhone knows up from down, or when you’re shaking it? It’s all because of the tiny accelerometer chip inside the device, but how does it work? It’s not like the iPhone’s got a metal ball bearing rolling between two points in there, so what gives?
As it turns out, there’s actually a lot of crazy cool tech in there.
Surprisingly, the way an accelerometer works is actually not that different from the ball bearing example above, as Bill Hammack the the Engineer Guy explains. It’s just a lot smaller scale.
Essentially, in every accelerometer, you have these extremely, springs made out of silicon, which oscillate back and forth between contact points. When they move according to the force of gravity, those contact points can measure the charge, and figure out which way the iPhone is pointing and how it’s moving.
These springs are tiny. So tiny that they’re about the size of a pencil tip. So how do you build a spring that small? That’s an even more fascinating story, involving tiny wafers of silicon covered in an interlacing series of masks which are impervious to a corrosive bath of potassium hydroxide.
That’s a lot of crazy super science packed into an iPhone chip that is estimated to only cost Apple sixty five cents.