Accelerometers
Fremantle offers the possibility to play with accelerometers. There is a plan to offer a proper interface for accelerometers in Maemo, but if you want to try out before there are a couple of ways to do it.
See also the related thread in talk.maemo.org.
D-Bus
Thomas Thurman (marnanel) has put together a simple demo of an application using accelerometers using the D-Bus interface. You can find sources and .deb up at http://people.collabora.co.uk/~tthurman/sandcastle/
sysfs
Another way is to use the sysfs file information.
/sys/class/i2c-adapter/i2c-3/3-001d/coord
When reading that file you get 3 values X, Y and Z. Values are in mG (milli G). 1000 = 1 G
- On the table face up values are 0, 0, -1000 (face down would read 0, 0, 1000)
- On the table on botton side (landscape): 0, -1000, 0
- On the table on right side (portrait): -1000, 0, 0
- In any other position any mix of those 3 values.
These are theoretical values. In real life your mileage will vary.