R1-D1-ESP-HOMEASSISTANT-ARDUINO.ino

#include <ESP8266WiFi.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <ArduinoHA.h>

const char* mqttHost = "homeassistant.local";
const char* ssid     = "";
const char* password = "";
const char* mqttUser = "";
const char* mqttPass = "";

byte mac[]   = {0x00, 0x10, 0xFA, 0x6E, 0x38, 0x4A};

#define ONE_WIRE_BUS 4          // DS18B20 on GPIO4 (D2)
#define PHOTO_PIN    A0         // photo-resistor voltage divider on ADC0

OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

HADevice device(mac, sizeof(mac));
WiFiClient wifiClient;
HAMqtt mqtt(wifiClient, device);

HASensorNumber ambientTemp("ambient_temp", HASensorNumber::PrecisionP2);
HASensorNumber lightLevel ("light_lvl",   HASensorNumber::PrecisionP0);

void setup() {
  Serial.begin(9600);
  sensors.begin();

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) { delay(500); }

  device.setName("TempLightController");   // rename if you like

  ambientTemp.setUnitOfMeasurement("°C");
  lightLevel .setUnitOfMeasurement("%");

  ambientTemp.

  mqtt.begin(mqttHost, 1883, mqttUser, mqttPass);
}

void loop() {
  mqtt.loop();

  static uint32_t last = 0;
  if (millis() - last > 5000) {          // every 5 s
    last = millis();

    /* --- ambient temperature --- */
    sensors.requestTemperatures();
    float tempC = sensors.getTempCByIndex(0);
    ambientTemp.setValue(tempC);
    Serial.print("Temp °C: ");
    Serial.println(tempC);

    /* --- light level --- */
    int raw = analogRead(PHOTO_PIN);     // 0–1023
    float pct = (raw / 1023.0) * 100.0;  // 0–100 %
    lightLevel.setValue(pct);
    Serial.print("Light %: ");
    Serial.println(pct);
  }
}