How can I replace delay() by millis()? - c

Question

After a while, I get my final result I want but I can't use delay because I need different time for different strip, so I need to replace delay() by millis() in this code:
#include <FastLED.h>
#define NUM_LEDS1 10
#define NUM_LEDS2 6
#define DATA_PIN1 6
#define DATA_PIN2 7
CRGB leds1[NUM_LEDS1];
CRGB leds2[NUM_LEDS2];
void setup() {
FastLED.addLeds<NEOPIXEL, DATA_PIN1>(leds1, NUM_LEDS1);
FastLED.addLeds<NEOPIXEL, DATA_PIN2>(leds2, NUM_LEDS2);
}
int dot_delay1[ ] = { 100,200,300,400,500,600,700,800,900,1000 };
int dot_delay2[ ] = { 100,200,300,400,500,600 };
void loop() {
for(int dot = 0; dot < NUM_LEDS1; dot++)
for(int dot = 0; dot < NUM_LEDS2; dot++)
{
leds1[dot] = CRGB::Blue;
leds2[dot] = CRGB::Blue;
FastLED.show();
leds1[dot] = CRGB::Black;
leds2[dot] = CRGB::Black;
delay( dot_delay1[ dot ] );
// this is where I need to put the second delay,
// but I can't put more then 1 delay.
// I need to refactor my code with millis() function instead of delay()
}
}

Answer 1

You can use non-blocking code patterns, which are executed in special frequencies or times. In the following, I give you an short example how you can replace a delay(1000) and a delay(5000) without blocking the main loop. In addition, you can check stackoverflow for similar posts (e.g. Pause without Delay() arduino).
// 1 sec. frequency
unsigned long interval=1000; // the time we need to wait
unsigned long previousMillis=0; // millis() returns an unsigned long.
// 5 sec. frequency
unsigned long interval1=5000; // the time we need to wait
unsigned long previousMillis1=0; // millis() returns an unsigned long.
void setup() {
//...
}
void loop() {
// other CMD's...
// replace delay(1000)
if ((unsigned long)(millis() - previousMillis) >= interval) {
previousMillis = millis();
// every first second
// ...
}
// other CMD's...
// replace delay(5000)
if ((unsigned long)(millis() - previousMillis1) >= interval1) {
previousMillis1 = millis();
// every fifth second
// ...
}
// other CMD's...
}

Answer 2

I see you're using NeoPixels! It just so happens that Adafruit has some great tutorials on using millis() and micros() for timing purposes instead of delay(). They also include good material on interrupts, if you're feeling ambitious and want to separate your timing from your main function entirely (a worthwhile undertaking, if you have the time and resources).
Part 1 (basics of using millis()):
https://learn.adafruit.com/multi-tasking-the-arduino-part-1/overview
Part 2 (introduces interrupts):
https://learn.adafruit.com/multi-tasking-the-arduino-part-2/overview
Part 3 (puts everything together):
https://learn.adafruit.com/multi-tasking-the-arduino-part-3/overview
Edit 1:
Alright, I edited your code, adding in a loop that checks for both delay periods to be done using millis(). I attempted to stick to the variable naming conventions that you've been using, for easy readability. There were also some other issues with your code syntax that I cleaned up. Make sure to effectively comment your code so that it's understandable, for yourself and for others!
Hopefully this works the way you want it to!
/*The goal of the sketch is to run multiple strip where each dot could be
controlled on/off one after the others but with different times on/off between each
pixel on each strip. All be independent and separate and automated and structured
already like FastLED library recommendation.*/
// Library include
#include <FastLED.h>
#define NUM_LEDS1 10
#define NUM_LEDS2 6
// Define pin (each strip be connected on)
#define DATA_PIN1 5
#define DATA_PIN2 6
// Declare some strip name and attribute (number of led per strip)
CRGB leds1[NUM_LEDS1];
CRGB leds2[NUM_LEDS2];
void setup() {
FastLED.addLeds<NEOPIXEL, DATA_PIN1>(leds1, NUM_LEDS1);
FastLED.addLeds<NEOPIXEL, DATA_PIN2>(leds2, NUM_LEDS2);
}
int dot_delay1[] = {100, 200, 300, 400, 500, 600, 700, 800, 900, 1000};
int dot_delay2[] = {100, 200, 300, 400, 500, 600};
void loop() {
for (int dot1 = 0; dot1 < NUM_LEDS1; dot1++) {
for (int dot2 = 0; dot2 < NUM_LEDS2; dot2++) {
// LED turns blue
leds1[dot1] = CRGB::Blue;
leds2[dot2] = CRGB::Blue;
// Show LED status
FastLED.show();
// LED turns black
leds1[dot1] = CRGB::Black;
leds2[dot2] = CRGB::Black;
// Create timing variables
unsigned long previousMillis = millis();
unsigned long currentMillis = millis();
// Create boolean variables to monitor if the delays have triggered yet
bool delayFlag1 = false, delayFlag2 = false;
// Loop continuously
while (1) {
currentMillis = millis();
// If the first delay time has passed, delayFlag1 is true
if ((unsigned long)(millis() - previousMillis) >= dot_delay1[dot1]) {
delayFlag1 = true;
}
// If the second delay time has passed, delayFlag2 is true
if ((unsigned long)(millis() - previousMillis) >= dot_delay2[dot2]) {
delayFlag2 = true;
}
// If both delay times have passed (both delay flags are true), exit while loop
if ((delayFlag1 && delayFlag2) == true) {
break;
}
}
}
}
}
This new code should work, I've tested it and it works as expected on my machine.
As a side note, your original question was "How can I replace delay() by millis()?". This question has been answered both by myself and by the previous answer author, user3704293. In the future it may be helpful to separate your questions to get higher quality answers and to better serve those who are searching for answers to the same questions. Once your question is answered, as I hope this question is now, you should accept the answer that is the best for you.
Let me know if it all works out!
Edit 2:
To have LEDs change independently of each other, replace the loop() function in the previous code with this one.
void loop() {
// Create timing variable
unsigned long previousMillis = millis();
// Loop through all LEDs
for (int dot = 0; dot < NUM_LEDS1; dot++) {
// If the first delay time has passed, change first LED strip
if ((unsigned long)(millis() - previousMillis) >= dot_delay1[dot1]) {
leds1[dot - 1] = CRGB::Black;
leds1[dot] = CRGB::Blue;
}
// If the second delay time has passed, change second LED strip
if ((unsigned long)(millis() - previousMillis) >= dot_delay2[dot2]) {
leds2[dot - 1] = CRGB::Black;
leds2[dot] = CRGB::Blue;
}
// Show LEDs
FastLED.show();
}
// Turn last LED Black
leds1[9] = CRGB::Black;
}