A Whole Lotta Shakin’ Goin’ On in Apple’s Newest Powerbooks

[This article was also posted to The Farm]

The latest generation of PowerBooks have an accelerometer whose


is park the hard drive’s heads in the case of sudden acceleration

(which typically happens when you drop it). Although this feature


new to laptops — some IBM laptops had this feature prior to Apple’s

incorporation of it — it took some PowerBook hackers to really take

advantage of it.

Photo: PowerBook rotation axes for it built-in accelerometer.

Amit Singh over at has a pretty complete page

describing the accelerometer, which Apple calls the AMS, short for

“Apple Motion Sensor”. Even better, he’s been

able to tap into it and

write applications that use the AMS’ data!

Screen shot:

  AMS Visualizer.


Visualizer is an app that uses OpenGL to render a 15″


hanging in space. The image in the window reflects the PowerBook’s

orientation: tilt the PowerBook to the left, and the image in the app

also tilts left; tip it back, and you’re treated to an underside view


Screen shot:

  Stable Window.



is an app that draws a window that stays level with respect to the

ground. If you tilt your Powerbook in one direction, the app tilts the

window an equal amount in the opposite direction.

Someone should bring an AMS-equipped PowerBook to the Santa Cruz Mystery Spot

and try this app out!

Screen shot:

  The Perturbed Desktop.

The Perturbed Desktop

is the aforementioned Stable Window taken to a silly extreme: it tilts

all the windows on your desktop based on a combination of factors

including the orientation of your PowerBook.

Matt Webb at took the approach even further and wrote, a

Python script that uses the accelerometer to control


This application lets you jump to the next track by tilting the


backwards and to the previous track by tilting it forwards. Don’t like

the current song? Give your PowerBook a light whack and you’ll skip to

the next one.

(This is a wonderful embodiment of Joey’s Rule of the Percussive

Maintenance of Machinery: “Hitting it once is maintenance; hitting it

twice is abuse.”)

One reply on “A Whole Lotta Shakin’ Goin’ On in Apple’s Newest Powerbooks”

Can you use this to make a PowerBook reboot if you turn it upside down and shake it?

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