[VicPiMakers Projects] Make class out of functions

[Mark G.]

Hi George,

Here's a quick outline of an ActionTimer class.  What
do you make of it?

Mark


On 2020-11-15 6:07 p.m., George Bowden wrote:
> I have two "identical" functions for time slicing the Arduino loop.  One 
> function is called to see if it is time to toggle the LED every second, 
> and the other "identical" function is called to see if it is time to 
> send a post to the website every few minutes.  These functions seem good 
> candidates for a single C++ class, and I'm looking for some 
> advice, never having coded a class before.  Maybe it's a coding 
> challenge? I'm using Arduinos millis() which increments continuously and 
> the modulus of that, with a different period value passed to the 
> functions, to determine when to act.  When the modulus remainder is 
> smaller than the last time through the loop, it is time to take action. 
> (the vertical line in the stairs)
> 
> image.png
> 
> 
> 
> Each instance of the class needs its own static variable for the value 
> of mod'ed millis() last time through the loop.   I would like to write a 
> class which I instantiate with NEW for each different period, ....  I 
> would like to put these in a library that I could include in any of my 
> projects that need time sliced
> 
>   Here is how I have coded it as functions:
> 
> unsigned long lastPostMillis=0;  // the value of the modulus last time 
> through the loop.
> unsigned long lastBlinkMillis=0;
> 
> bool isPostTime(unsigned long int period){
>    if(millis() % period > lastPostMillis) {
>      lastPostMillis = millis()% period;
>      return true;
>    }
>    else {
>      lastPostMillis = millis() % period;
>      return false;
>    }
> }
> bool isBlinkTime(unsigned long int period){
>    int blinkPeriod = 500;
>    if(millis() % blinkPeriod > lastBlinkMillis) {
>      lastBlinkMillis = millis()% period;
>      return true;
>    }
>    else {
>      lastBlinkMillis = millis()% period;
>      return false;
>    }
> }
> void setup() {...
> }
> void loop() {
>    if (isPostTime(minutesBetweenPosts*60000)) { //time to send a Post to 
> the website
>    ...
>    if(isBlinkTime(500)){
>      toggle builtin led}
> } // end loop
> -- 
> George Bowden, 250-893-7423
> gtbowdeng at gmail.com
> <mailto:gtbowdeng at gmail.com>
> 
-------------- next part --------------

#include "action_timer.h"

const long int milliseconds_per_minute = 60000;
const long int post_period_minutes = 5; 
const long int post_period = post_period_minutes * milliseconds_per_minute;

const long int blink_period = 500;  // milliseconds

ActionTimer poster(post_period);
ActionTimer blinker(blink_period);

void setup() {...
}


void loop() {
    if (blinker.is_action_time()) {
        toggle built in led;
    } 
    if (poster.is_action_time()) {
        post action;
    } 
} // end loop

-------------- next part --------------
#ifndef ACTION_TIMER_H
#define ACTION_TIMER_H

/* Declarations for action timer class.  
 * Mark G. 2020-11-15
 */

const long int default_millis = 1000; // 1 sec

class ActionTimer {
  public:

    ActionTimer() { period = default_millis; }
    ActionTimer(long int period_millis) { period = period_millis; }

    bool is_action_time();

    void set_period(long int p) { period = p; };
    long int get_period() { return period; }

  private:
    long int period = 0;  // milliseconds
    long int last_action_millis = 0;

};

#endif
-------------- next part --------------

/* Definitions for an action timer class.  
 * Mark G. 2020-11-15
 */

#include "action_timer.h"

bool ActionTimer::is_action_time() 
{
  if(millis() % period > last_action_millis) {
    last_action_millis = millis() % period;
    return true;
  }
  else {
    last_action_millis = millis() % period;
    return false;
  }
}