## Accelerometers
* Input that detects movement and orientation; e.g. the wiimote
* Use 'relative' inputs as numbers
  * Acceleration along the x,y, and z axes up to 3g (gravity force, where 1 G = earth gravity)
  * For example: if pointed upwards, will have 1g along the Y axis, 0g along the z axis
  
## Common HID (Human Interface Device) code features
* Deadzones
* Analog input filtering
  * low-pass filter or running average
* Event detection
* button sequences (combos) or multi-button presses at the same time (chords)
* gesture detection
* multi-controller support
* Multi-platform abstraction 
  *cross platform support for different controller types
* Input remappiong
* Context-sensitive input
* Input disabling (e.g. for cutscenes)

## Button sequence detection (e.g. fighting game button combo)

* Keep a history of the last pressed button in the expected sequence
  and the time it was pressed
* When the next button in the sequence is pressed
  * If the button was pressed within the time limit, update the sequence
  * else reset the sequence to the beginning (sequence failed)