Non-blocking led loop

Projects Programming
1

Hi guys, im looking for some help getting the function airStrobe() to be non-blocking. I get the concept but I just carn't seem to get my head around this nested non-blocking code. Below is the original code with delays, and also my attempt at making it non-blocking. Thanks

Code with delays:

void airStrobe(int t) {
  static unsigned long previousUpdateTime;
  if(millis()-previousUpdateTime > t){
    previousUpdateTime = millis();
    digitalWrite(ledPins[0], HIGH);
    digitalWrite(ledPins[1], HIGH);
    delay(50);   
    digitalWrite(ledPins[0], LOW);
    digitalWrite(ledPins[1], LOW);
    delay(100);   
    digitalWrite(ledPins[0], HIGH);
    digitalWrite(ledPins[1], HIGH);
    delay(50);
    digitalWrite(ledPins[0], LOW);
    digitalWrite(ledPins[1], LOW);
    delay(10);
    digitalWrite(ledPins[2], HIGH);
    digitalWrite(ledPins[3], HIGH);
    delay(50);   
    digitalWrite(ledPins[2], LOW);
    digitalWrite(ledPins[3], LOW);
    delay(100);   
    digitalWrite(ledPins[2], HIGH);
    digitalWrite(ledPins[3], HIGH);
    delay(50);
    digitalWrite(ledPins[2], LOW);
    digitalWrite(ledPins[3], LOW);
  }
}

Attempt at non-blocking code:

const int pinCount = 4;
static unsigned long previousUpdateTime;

void setup()  {   
  for (int thisPin = 0; thisPin < pinCount; thisPin++)  {
    pinMode(ledPins[thisPin], OUTPUT);  
  }
} 

void loop()  {
  airStrobe(3000);
}

void airStrobe(int t) {
  if(millis()-previousUpdateTime > t){
  
    static unsigned long updateDelay;    
    static unsigned long blinkDelay = millis()-updateDelay; // non-blocking var
    
    if(blinkDelay < 50) {
      previousUpdateTime = millis();
      digitalWrite(ledPins[0], HIGH);
      digitalWrite(ledPins[1], HIGH); 
    } else if(blinkDelay >= 50 && blinkDelay < 150)  { //delay(50);  
      digitalWrite(ledPins[0], LOW);
      digitalWrite(ledPins[1], LOW);
    } else if(blinkDelay >= 150 && blinkDelay < 200) { //delay(100);
      digitalWrite(ledPins[0], HIGH);
      digitalWrite(ledPins[1], HIGH);
    } else if(blinkDelay >= 200 && blinkDelay < 210) { //delay(50);
      digitalWrite(ledPins[0], LOW);
      digitalWrite(ledPins[1], LOW);
    } else if(blinkDelay >= 210 && blinkDelay < 260) { //delay(10);
      digitalWrite(ledPins[2], HIGH);
      digitalWrite(ledPins[3], HIGH);      
    } else if(blinkDelay >= 260 && blinkDelay < 310) { //delay(50);
      digitalWrite(ledPins[2], LOW);
      digitalWrite(ledPins[3], LOW);
    } else if(blinkDelay >= 310 && blinkDelay < 410) { //delay(100);
      digitalWrite(ledPins[2], HIGH);
      digitalWrite(ledPins[3], HIGH);
    } else if(blinkDelay >= 410 && blinkDelay < 460) { //delay(50);
      digitalWrite(ledPins[2], LOW);
      digitalWrite(ledPins[3], LOW);
    } else if(blinkDelay >= 460) {
      updateDelay = millis();
    }
    
  }
}
2
3

You declare a variable blinkDelay, but never assign it a value.

4

Arrch:
You declare a variable blinkDelay, but never assign it a value.

Is this any better ?

void airStrobe(int t) {
  if(millis()-previousUpdateTime > t){
  
    static unsigned long blinkDelay = millis(); // non-blocking var
    
    if(blinkDelay < 50) {
      previousUpdateTime = millis();
      digitalWrite(ledPins[0], HIGH);
      digitalWrite(ledPins[1], HIGH); 
      Serial.println("airStrobe: 1");    
    } else if(blinkDelay >= 50 && blinkDelay < 150)  { //delay(50);  
      digitalWrite(ledPins[0], LOW);
      digitalWrite(ledPins[1], LOW);
      Serial.println("airStrobe: 2");   
    } else if(blinkDelay >= 150 && blinkDelay < 200) { //delay(100);
      digitalWrite(ledPins[0], HIGH);
      digitalWrite(ledPins[1], HIGH);
      Serial.println("airStrobe: 3");    
    } else if(blinkDelay >= 200 && blinkDelay < 210) { //delay(50);
      digitalWrite(ledPins[0], LOW);
      digitalWrite(ledPins[1], LOW);
      Serial.println("airStrobe: 4");
    } else if(blinkDelay >= 210 && blinkDelay < 260) { //delay(10);
      digitalWrite(ledPins[2], HIGH);
      digitalWrite(ledPins[3], HIGH);      
      Serial.println("airStrobe: 5");
    } else if(blinkDelay >= 260 && blinkDelay < 310) { //delay(50);
      digitalWrite(ledPins[2], LOW);
      digitalWrite(ledPins[3], LOW);
      Serial.println("airStrobe: 6");
    } else if(blinkDelay >= 310 && blinkDelay < 410) { //delay(100);
      digitalWrite(ledPins[2], HIGH);
      digitalWrite(ledPins[3], HIGH);
      Serial.println("airStrobe: 7");
    } else if(blinkDelay >= 410 && blinkDelay < 460) { //delay(50);
      digitalWrite(ledPins[2], LOW);
      digitalWrite(ledPins[3], LOW);
      Serial.println("airStrobe: 8");
    } else if(blinkDelay >= 460) {
      blinkDelay = 0;
    }
    
  }
}
5

It has a value, but it never changes:

    static unsigned long blinkDelay = millis()-updateDelay; // non-blocking var

Using "static" means it is only computed once. Try removing "static".

6

Now it is only ever set to 0.

7

Try using not led but printing on serial monitor.
on setup:

void setup()  
{ delay(1000);
  Serial.begin(9600);
  ...

First time only okay, after it reach 9 no restart:

void airStrobe(int t) {
  if(millis()-previousUpdateTime > t)
  { static unsigned long updateDelay=millis();    
    static unsigned long blinkDelay=0; // non-blocking var
    
    blinkDelay=millis()-updateDelay;
    Serial.print(blinkDelay); Serial.print("="); Serial.print(millis()); Serial.print("-"); Serial.println(updateDelay);
    if(blinkDelay < 50) {
      Serial.println("1");
    } else if(blinkDelay >= 50 && blinkDelay < 150)  { //delay(50);  
      Serial.println("2");
    } else if(blinkDelay >= 150 && blinkDelay < 200) { //delay(100);
      Serial.println("3");
    } else if(blinkDelay >= 200 && blinkDelay < 210) { //delay(50);
      Serial.println("4");
    } else if(blinkDelay >= 210 && blinkDelay < 260) { //delay(10);
      Serial.println("5");
    } else if(blinkDelay >= 260 && blinkDelay < 310) { //delay(50);
      Serial.println("6");
    } else if(blinkDelay >= 310 && blinkDelay < 410) { //delay(100);
      Serial.println("7");
    } else if(blinkDelay >= 410 && blinkDelay < 460) { //delay(50);
      Serial.println("8");
    } else if(blinkDelay >= 460) {
      Serial.println("9");
      updateDelay = millis();
      previousUpdateTime=millis();
    }
  }
}

because "static unsigned long updateDelay=..." is executed only first time.

8 
static unsigned long updateDelay=millis();

You totally decided to ignore my suggestion.

9

Not true. We need to remember previous value, so static seem to be useful.
I think it's not possible to find a solution follow this method. But I suggest @driz to use Serial.print to debug.

10

Now it seem to function:

const byte pinCount = 4;
unsigned long previousUpdateTime;

void setup()  {   
  delay(1000);
  Serial.begin(9600);
  //for (int thisPin = 0; thisPin < pinCount; thisPin++)  {
  //  pinMode(ledPins[thisPin], OUTPUT);  
  //}
} 

void loop()  {
  airStrobe(3000);
}

void airStrobe(int t) {
  if(millis()-previousUpdateTime > t)
  { static unsigned long updateDelay;    
    static unsigned long blinkDelay; // non-blocking var
    static boolean start=false;
    if(!start) 
    { start=true;
      updateDelay=millis();
    }   
    blinkDelay=millis()-updateDelay;
    Serial.print(blinkDelay); Serial.print("="); Serial.print(millis()); Serial.print("-"); Serial.println(updateDelay);
    if(blinkDelay < 50) {
      Serial.println("1");
    } else if(blinkDelay >= 50 && blinkDelay < 150)  { //delay(50);  
      Serial.println("2");
    } else if(blinkDelay >= 150 && blinkDelay < 200) { //delay(100);
      Serial.println("3");
    } else if(blinkDelay >= 200 && blinkDelay < 210) { //delay(50);
      Serial.println("4");
    } else if(blinkDelay >= 210 && blinkDelay < 260) { //delay(10);
      Serial.println("5");
    } else if(blinkDelay >= 260 && blinkDelay < 310) { //delay(50);
      Serial.println("6");
    } else if(blinkDelay >= 310 && blinkDelay < 410) { //delay(100);
      Serial.println("7");
    } else if(blinkDelay >= 410 && blinkDelay < 460) { //delay(50);
      Serial.println("8");
    } else if(blinkDelay >= 460) {
      Serial.println("9");
      updateDelay = millis();
      previousUpdateTime=millis();
      start=false;
    }
  }
}
11

nid69ita:
Not true. We need to remember previous value, so static seem to be useful.
I think it's not possible to find a solution follow this method. But I suggest @driz to use Serial.print to debug.

An assignment done on a "static" variable is done once. If you want to preserve the variable make the declaration one line, and the assignment another line.

12

Sorry Nick, I did try your suggestion but could not get it to work. However thank you for explaining to me what a static variable does

Thank you very much nid69ita ! your solution seems to work as intended and I will be using it :slight_smile:

You guys really are awesome and I appreciate your input very much. This truly is a great forum with some very helpful people and ideas.