/* y2. Esboçar um diagrama de ligações de Sonar e um Led (unicolor) 
ligado ao Arduino.
Implemente código arduino que faz com que uma distância [20,200] cm medida 
pelo sonar controla a frequência de ‘pisca’ intermitente do LED entre 1-80 Hz.
*/

#define echoPin 2 // attach pin D2 Arduino to pin Echo of HC-SR04
#define trigPin 3 //attach pin D3 Arduino to pin Trig of HC-SR04

// defines variables
long duration; // variable for the duration of sound wave travel
int distance; // variable for the distance measurement
float t, f;
int led = 4;

void setup() {
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an OUTPUT
  pinMode(echoPin, INPUT); // Sets the echoPin as an INPUT
  pinMode(led, OUTPUT);
  Serial.begin(9600); // // Serial Communication is starting with 9600 of baudrate speed
  Serial.println("Ultrasonic Sensor HC-SR04 Test"); // print some text in Serial Monitor
  Serial.println("with Arduino UNO R3");
}

void led_pisca() {
  digitalWrite(led, HIGH);
  Serial.print("Frequencia: ");
  Serial.println(f);
  delay(t);
  digitalWrite(led, LOW);
  delay(t);
}

void loop() {
  // Clears the trigPin condition
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin HIGH (ACTIVE) for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance = duration * 0.034 / 2; // Speed of sound wave divided by 2 (go and back)
  // Displays the distance on the Serial Monitor
  Serial.print("Distancia: ");
  Serial.print(distance);
  Serial.println(" cm");
  if(distance > 19 and distance < 201){
    f = map(distance, 20, 200, 1, 80);
    t = (1/f)*1000;
    led_pisca();
  } else {
    digitalWrite(led, LOW);
  }
  
}