The DS Motion Card is a three-dimensional montion sensor for the Nintendo DS.

“The DS Motion Card contains a Kionix tri-axis accelerometer and single-axis gyroscope that communicate with the DS using SPI (Serial Peripheral Interface) on the DS card.

The accelerometer measures acceleration in all directions (both gravitational acceleration and acceleration caused by a change in velocity). The gyroscope measures angular rotation rate (speed of rotation) around an axis perpendicular to the bottom screen of the DS.

Custom software turns the sensors on, reads the accelerations and angular rate, and controls the display based on the sensor readings. Functions to communicate with the sensors have already been written and are simple to integrate into any existing or new projects.”

The motion sensor fits tightly into the DS and allows you to play ‘physical driven games’, for example ball games or similar things. Unfortunatelly only homebrew is supported, because the device is not supported for official Nintendo stuff. There is also a similar device for the Game Boy Advance available, called GBAccelerometer. Unfortunatelly I don’t know if this device is also supported for the GBA-Slot in the Nintendo DS.