#include <WiFi.h>
#include <PubSubClient.h>

char clientID[50];
WiFiClient espClient;
PubSubClient client(espClient);

static char strDistance[10];
int ecoPin = 5;
int trigPin = 15;
int distance;
unsigned long time;

void setup() {
  WiFi.mode(WIFI_STA);

  WiFi.begin("your_wifi_ssid", "your_wifi_password");

  client.setServer("your_mqtt_server_address", 1883);

  pinMode(ecoPin, INPUT);

  pinMode(trigPin, OUTPUT);

  Serial.begin(9600);
}

void mqttReconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection…");
    if (client.connect(clientID)) {
      Serial.println("connected");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void loop() {
  if (!client.connected()) {
    mqttReconnect();
  }
  client.loop();

  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  time = pulseIn(ecoPin, HIGH);
  distance = time * 0.0341 / 2;
  Serial.println(distance);

  sprintf(strDistance, "%d", distance);
  client.publish("topicName/pir", strDistance);
  delay(1000);
}