ESP32 MQTT Sensor Dashboard

/*
 * ESP32 MQTT Dashboard — Advanced
 * Same hardware as intermediate; adds OTA + structured JSON for InfluxDB.
 * The Node-RED flow bridges MQTT → InfluxDB.
 * No code changes needed on the ESP32 side — only Node-RED configuration.
 *
 * InfluxDB Node-RED flow setup:
 *   1) Install: npm install node-red-contrib-influxdb
 *   2) Subscribe to "esp32engine/sensors/+/all" (wildcard for all rooms)
 *   3) JSON node → function node (add measurement name) → InfluxDB out node
 *
 * This sketch adds ArduinoOTA and a richer JSON payload with metadata.
 */
#include <WiFi.h>
#include <PubSubClient.h>
#include <ArduinoOTA.h>
#include <DHT.h>
#include <Wire.h>
#include <Adafruit_BMP280.h>
#include <time.h>

const char* SSID     = "YOUR_WIFI_SSID";
const char* PASSWORD = "YOUR_WIFI_PASSWORD";
const char* BROKER   = "192.168.1.100";
const char* DEV_ID   = "room1";
const char* LOCATION = "Living Room";

#define DHT_PIN 4
#define DHT_TYPE DHT22
#define MQ_PIN  34
#define PIR_PIN 27
#define LDR_PIN 35

DHT dht(DHT_PIN, DHT_TYPE);
Adafruit_BMP280 bmp;
WiFiClient net;
PubSubClient mqtt(net);

String topicAll  = String("esp32engine/sensors/") + DEV_ID + "/all";
String topicAvail= String("esp32engine/sensors/") + DEV_ID + "/availability";

void connectMQTT(){
  while(!mqtt.connected()){
    if(mqtt.connect(("esp32-"+String(DEV_ID)).c_str(),"","",
      topicAvail.c_str(),0,true,"offline")){
      mqtt.publish(topicAvail.c_str(),"online",true);
    } else delay(5000);
  }
}

void setup(){
  Serial.begin(115200);
  dht.begin(); Wire.begin(); bmp.begin(0x76);
  pinMode(PIR_PIN,INPUT);
  analogReadResolution(12);
  WiFi.begin(SSID,PASSWORD);
  while(WiFi.status()!=WL_CONNECTED) delay(400);
  configTime(0,0,"pool.ntp.org");
  ArduinoOTA.setHostname(("esp32-"+String(DEV_ID)).c_str());
  ArduinoOTA.begin();
  mqtt.setServer(BROKER,1883);
  connectMQTT();
}

void loop(){
  ArduinoOTA.handle();
  if(!mqtt.connected()) connectMQTT();
  mqtt.loop();

  static unsigned long last=0;
  if(millis()-last>=30000){
    last=millis();
    float t=dht.readTemperature(),h=dht.readHumidity();
    float p=bmp.readPressure()/100.0f;
    char ts[25]=""; struct tm ti;
    if(getLocalTime(&ti)) strftime(ts,sizeof(ts),"%Y-%m-%dT%H:%M:%SZ",&ti);

    // Enriched JSON: add device_id, location, and ISO8601 timestamp
    // InfluxDB line protocol can be generated in Node-RED from these fields
    String j = "{"device":""+String(DEV_ID)+"","
               ""location":""+String(LOCATION)+"","
               ""temperature":"+String(t,2)+","
               ""humidity":"+String(h,2)+","
               ""pressure":"+String(p,1)+","
               ""air_quality":"+String(analogRead(MQ_PIN))+","
               ""light":"+String(analogRead(LDR_PIN))+","
               ""motion":"+String(digitalRead(PIR_PIN))+","
               ""ts":""+ts+""}";
    mqtt.publish(topicAll.c_str(),j.c_str(),true);
    Serial.println(j);
  }
}