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

after while, final result want can't use delay because need different time different strip, need replace delay() millis() in 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 ] );       // need put second delay,       // can't put more 1 delay.       // need refactor code millis() function instead of delay()     } } 

you can use non-blocking code patterns, executed in special frequencies or times. in following, give short example how can replace delay(1000) , delay(5000) without blocking main loop. in addition, can check stackoverflow similar posts (e.g. pause without delay() arduino).

// 1 sec. frequency unsigned long interval=1000;    // time need wait unsigned long previousmillis=0; // millis() returns unsigned long.  // 5 sec. frequency   unsigned long interval1=5000;    // time need wait unsigned long previousmillis1=0; // millis() returns 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... }