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Apple Motion Sensor Driver (ams)

What is ams ?

ams is a Linux kernel driver for the motion sensor found on post February 2005 Apple Alu Powerbooks and newer IBooks.

The programming specifications for this device were obtained by Johannes Berg by reverse enginneering the Mac OSX driver, and are available here. This driver is implemented using a clean room approach from the above specifications.

The ams driver is not complete yet. It does not do anything special (except printing a message) when a shock or a free fall is detected (the OSX driver parks the hard disk drives when this is happenning).


Compile the driver and load the module.

In /sys/devices/ams you will find three files (x, y and z) which contain the sensor values for changes in each direction.

You can turn the ams driver into a mouse like input device by loading the module with the mouse option or at any time by writing 1 to /sys/devices/ams/mouse (writing 0 will disable the input device).


AMS reverse engineered specs
Some information about the AMS
Use the AMS as an input device (in OSX)

Filename Size Md5sum
ams-0.04.tar.bz2 4218 bytes 2058eb5497732d890284704e25efa30c
ams-0.03.tar.bz2 4230 bytes 39d38e36fc2475fb9d24e372fd602aa0
ams-0.02.tar.bz2 4228 bytes 78a19fe490356a062cf025ceb2051cc2
ams-0.01.tar.bz2 3688 bytes 46849cdfeb5cf75bd6bd151fb3478c5c

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Last modified: Wed May 24 11:21:12 CEST 2006 Valid HTML 4.01!