If you have a recent MacBook or MacBook Pro, chances are good that you have a built-in seismograph — an instrument that measures shaking. These are the things that are used to measure earthquakes.
What you have in your laptop is actually a Sudden Motion Sensor. This is a cute little device that tries to determine if your laptop has been dropped or otherwise jolted. If so, it parks the hard drive, hopefully preventing damage. That’s pretty cool on it’s own, but what’s even cooler is that there’s a way for applications to read the sensor and use it’s data.
Enter SeisMac and iSeismograph. Both programs display, in real time, the data from the Sudden Motion Sensor. The chip measures the acceleration in all three dimensions. In particular that means the vertical axis will always report 1 “g” of acceleration, as long as the computer is level. If you’re like me, that’s a dangerous thing to know, because you will then be tempted to find out if your laptop can achieve free-fall. (It turns out the answer is “yes”.) With iSeismograph (which seems to be the one with a lot more bells and whistles) you can also make a 2 dimentional plot of, say, the X axis versus the Y axis, and then try to use it as an Etch a Scetch.
Is this useful? Possibly. There’s an idea to use this to report seismic events to get better resolution earthquake data, SETI@HOME-style. Each computer would report seismic events to a central database, where detailed analysis could be done. The Quake-Catcher Network is actually doing this. They’ve made some good progress solving the obvious problems of how to determine the computers location, and how to tell an earthquake apart from a cat. The press release for iSeismograph also mentions a number of other good educational applications.
Mainly, though, it’s just really cool.
How recent is recent? This is dangerous knowledge… my MacBook might not appreciate this very much. ๐
At least you’ve already tested free fall, so I don’t have to. ๐
According to Apple, they started using the sensors in 2005, so not that recent in computer-years.
It’s definitely dangerous. At some point I was shaking the computer around, and I suddenly though, “Here’s my computer, on which is stored an amazingly large number of important things, and which I depend on to connect to the rest of the world, and I’m shaking it vigorously and dropping it to make a little line move around on the screen.”
I want to say something like, “The things we do for science”; but really, it’s just about making a little line move around the screen.
Ah, then my MacBook should have this as well.
Must resist clicking the links… because goodness knows you’ll find me shaking my computer around too.
Um yes, all in the name of science… right? Or we’re just easily amused. Either way… ๐
There is certainly no limit to the ease with which I am amused, or the… oh! what’s that?