ArduinoScheduler documentation

Tasks

This module contains methods for Tasks, an attempt at concurrency:

• A Task is a combination of an action function and a closure function (both parameterless), and a Timer.
  • A Task triggers its action function after n amount of time, then triggers its closure function after m amount of time (from the time it was called): once, forever, or n times (excluding 0ms).

Using the module

To create a Task, you must first create an action function and its corresponding closure function (both parameterless) in the global scope, ex:

void turnOnRelay(void){
    ...
}
void turnOffRelay(void){
    ...
}

Then, you must create the corresponding Timer structure globally, ex:

...
TaskTimer relayTimer = {.f_ms=2000, .cf_ms=5000, .callTime=0, .ACTION=1, .REPEAT=-1};
...

or do it in setup, ex:

setup(){
  setTaskTimer(&relayTimer, 2000, 5000, -1);
  ...
}

where:

void setTaskTimer(TaskTimer *taskTimer, f_ms, cf_ms, REPEAT);

• f_ms refers to the interval of time before the action function is activated.

  • i.e how long does the Task stay inactive?

• cf_ms refers to the interval of time before the closure function is activated.

  • i.e how long does the Task stay active?

• REPEAT has the following options:

  • =n : Do this Task n times
  • =-1 : Repeat this Task forever.

Finally, you can enqueue the Task inside the Arduino loop():

void loop() {
  enqueueTask(turnOnRelay, turnOffRelay, &relayTimer);
  ...
}

NOTE: If you would like to use functions with parameters, then you need to apply the logic found in the enqueue functions manually.

WARNING: These methods are bound by the loop() iteration duration: If your Timer is set to 40s, but the iteration has a 50s delay after the method is called, then your Event/Task will be triggered after 50s, not 40s.

WARNING: The internal clock (milis) is an unsigned long int, thus it overflows at 4,294,967,295 (2^32 - 1, unsigned long max) (roughly 50 days) before rolling over to 0. This means that you should somewhat expect unexpected behaviour if you leave the Arduino on for that long.

Creating libraries for the Arduino & Usage

To create libraries, you must create a folder <Library> containing:

1. <Library>.h -> Your header file
2. <Library>.cpp -> Your code

Then you must place <Library> inside Documents/Arduino/libraries. You should then be able to load them inside the IDE with Sketch->Include Library

NOTE: The module must be in .cpp or else you must put the header file inside an ugly wrapper, check out https://stackoverflow.com/questions/19635007/arduino-c-undefined-reference-to-readarms for more info.