为什么红灯不亮？

Question

So I am very new to this IOT stuff and what I am trying to create here is somewhat like traffic violation and my idea is when the red light is on and if the PIR sensor detects the moment the buzzer/led goes high.

Here's the image:

Here's what the code looks like

int pir = 2;
int rojo = 12; 
int amarillo = 11;
int verde = 10;
int led = 7;

void setup()
{
  pinMode(pir, INPUT);
  pinMode(led, OUTPUT);
  Serial.begin(9600);
  pinMode(verde, OUTPUT); //It declares the green pin as output 
  pinMode(amarillo, OUTPUT);//It declares the yellow pin as output 
  pinMode(rojo, OUTPUT);
}
    
void loop()
{
  digitalWrite(verde, HIGH); //It turns on the green led 
  delay(15000); //wait 15 seconds 
  digitalWrite(verde, LOW); //It turns off the green led 
  delay(250); //wait 0.25 seconds
  
  digitalWrite(amarillo, HIGH); //It turns on the yellow led 
  delay(3000); //wait 3 seconds 
  digitalWrite(amarillo, LOW); //It turns off the yellow led 
  delay(250); //wait 0.25 seconds
  int val = digitalRead(pir);
  Serial.println(val);
    
  digitalWrite(rojo, HIGH); //It turns on the red led 
  delay(15000); //wait 15 seconds 
  digitalWrite(rojo, LOW);
  if (rojo == HIGH) {
    if (val == HIGH) {
      digitalWrite(led, HIGH);
    } else {
      digitalWrite(led, LOW); 
    }
    delay(10);
  }
}

Answer 1

The problem is here:

  digitalWrite(rojo, HIGH); //It turns on the red led 
  delay(15000); //wait 15 seconds 
  digitalWrite(rojo, LOW);
  if (rojo == HIGH) {
    if (val == HIGH) {
      digitalWrite(led, HIGH);
    } else {
      digitalWrite(led, LOW); 
    }
    delay(10);
  }

First of all, rojo is a pin number, not a value you want to use in this compare.

Second, during your delay delay(15000) , the code stops running, so movement is not detected during this time.

The only way to detect during the 15s delay is by using millis() for your timing and delay (or using an interrupt).

You could try something like this (untested):

digitalWrite(rojo, HIGH); //It turns on the red led 
unsigned long int redStartTime = millis();
while (millis() - redStartTime <= 15000) {
  delay(100);
  int val = digitalRead(pir);
  if (val == HIGH) {
    digitalWrite(led, HIGH);
  } else {
    digitalWrite(led, LOW); 
  }
}
digitalWrite(rojo, LOW);

I didn't test this, but I hope you get the idea.

Note that I don't know if the motion detector returns HIGH or LOW when something moves; you may need to change the code there.

Answer 2

You need to change the position of your if

int pir=2;
int rojo=12; 
int amarillo=11;
int verde=10;
int led=7;

void setup()
{
    pinMode(pir,INPUT);
    pinMode(led,OUTPUT);
    Serial.begin(9600);
    pinMode(verde,OUTPUT); //It declares the green pin as output 
    pinMode(amarillo,OUTPUT);//It declares the yellow pin as output 
    pinMode(rojo,OUTPUT);
}
    
void loop()
{
    digitalWrite(verde,HIGH); //It turns on the green led 
    delay(15000); //wait 15 seconds 
    digitalWrite(verde,LOW); //It turns off the green led 
    delay(250); //wait 0.25 seconds
    
    digitalWrite(amarillo,HIGH); //It turns on the yellow led 
    delay(3000); //wait 3 seconds 
    digitalWrite(amarillo,LOW); //It turns off the yellow led 
    delay(250); //wait 0.25 seconds
    int val = digitalRead(pir);
    Serial.println(val);
    
    digitalWrite(rojo,HIGH); //It turns the red led 
    if(val==HIGH){             //---> //I dont know if this value can be compared with HIGH, on my programm whe costum use numbers!
        digitalWrite(led,HIGH);
    }
    else{
        digitalWrite(led,LOW); 
    }
    delay(15000); //wait 15 seconds 
    digitalWrite(rojo,LOW);
    delay(10);
}