SLOVED, Sound in void loop with time?

Using Arduino Programming Questions
#1

Need me to change this code for sound make delay 5s without delay 5s to all void loop code?

if(battery_level < 6.1)
{
  if(sound)
     { 
       delay(250);
       digitalWrite(buzzer,HIGH);
       delay(250);
       digitalWrite(buzzer,LOW); 
       delay(5000);
    }
}

All void loop code stop working 5s, how to change this sound code to repeat every 5s without stop looping code?

#2

See the blink without delay example in the IDE examples:
File -> Examples -> Digital -> Blink without delay

#3

This code working perfect

const byte speakerPin=9;
unsigned long lastPeriodStart;
const int onDuration=1000;
const int periodDuration=6000;

void setup()
{}

void loop()
{
  if (millis()-lastPeriodStart>=periodDuration)
  {
    lastPeriodStart+=periodDuration;
    tone(speakerPin,550, onDuration); // play 550 Hz tone in background for 'onDuration'
  }
}
#4