Action sequences are a way of defining a sequential actions that the library will execute to move the vehicle (ie, a 'recipe' for movement). They save time in not having to program common combinations of actions and monitoring each completion in the application sketch. The library executes the action sequence in the background freeing the application to run other higher priority tasks.

An simple example is when a front bump switch detects a collision, triggering the evasive action defined by:

stop the vehicle
pause a short while
reverse away from the obstacle
pause a short while
spin to another direction
resume normal vehicle motion

These actions can be defined in a list of actions to be performed and passed to the library for execution:

static const PROGMEM MD_SmartCar::actionItem_t seq[] =
{
  { MD_SmartCar::STOP },
  { MD_SmartCar::PAUSE, 300 },
  { MD_SmartCar::MOVE,  -PI, -PI },
  { MD_SmartCar::PAUSE, 300 },
  { MD_SmartCar::SPIN,  -25 },
  { MD_SmartCar::END }
};

The action sequence is defined as an array of MD_SmartCar::actionItem_t records. Each record contains the action to be performed and the parameters relevant to that action (summarized in the table below). The last record in the array must always be the END action or the library will continue reading random memory beyond the end of the sequence.

Sequences may be completely predefined, allowing them to be stored in static (PROGMEM) memory to preserve dynamic RAM, or they may be built and/or modified 'on the fly' in RAM.

The list of actions that can be defined an actionItem_t are listed given by the enumerated type MD_SmartCar::actionId_t.

ActionId_t	Comment	Parameter 0	Parameter 1
MD_SmartCar::DRIVE	executes drive()	Linear Velocity	Angular Velocity
MD_SmartCar::MOVE	executes move()	Left rotate	Right rotate
MD_SmartCar::SPIN	executes spin()	Spin percentage	Not used
MD_SmartCar::PAUSE	executes pause	Milliseconds	Not used
MD_SmartCar::STOP	executes stop()	Not used	Not used
MD_SmartCar::END	marks seq end	Not used	Not used