[This article was also posted to The Farm]
The latest generation of PowerBooks have an accelerometer whose
purpose
is park the hard drive’s heads in the case of sudden acceleration
(which typically happens when you drop it). Although this feature
isn’t
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.
Amit Singh over at Kernelthread.com 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!
The AMS
Visualizer is an app that uses OpenGL to render a 15″
PowerBook
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
onscreen.
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!
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 Interconnected.org took the approach even further and wrote bumptunes.py, a
Python script that uses the accelerometer to control
iTunes.
This application lets you jump to the next track by tilting the
machine
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.”)
