HC SR04 - detection 5 seconds

Other Hardware Sensors
1

I want to detect if an obstacle is for 5 seconds in front of my sensor then have to happen something... but i'm stuck... thanks for any help

int led = 12;
int trigger = 5;
int echo = 4;

void setup() {

  pinMode(led, OUTPUT);
  pinMode(trigger, OUTPUT);
  pinMode(echo, INPUT);


  // put your setup code here, to run once:

}

void loop() {

  unsigned long startTime = 0;

  digitalWrite(trigger, LOW);

  digitalWrite(trigger, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigger, LOW);

  long duration = pulseIn(echo, HIGH);
  long distance = 0.034 * duration / 2;

  if (distance > 10)
  {
    startTime = millis();
  }
  else {

    if (millis() - startTime >= 5000) 
    {
      ....
    }
  }
}
2

Assuming that you are trying to trigger something if distance stays below 10 for 5 seconds then your logic is basically OK- whatever you place in the "if (millis() - startTime >= 5000)" clause will get executed after 5 seconds. However as it looks now the clause will trigger continuously once 5 seconds has elapsed- if this is not what you want then add a flag or set starttime to be far in the future once you execute the trigger.

3

I have to find a way to detect an obstacle after 5 seconds that it's in front of sensor.
If put my hand in front of it and after 5 seconds play a song, after 10 seconds play another song, etc...

4

What is your code to play the song? Are you going to generate tones directly using the arduino tone() function or are you using the arduino to trigger something else?