#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>

#define DHTPIN PA1      // D1 on Blue Pill
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);

LiquidCrystal_I2C lcd(0x27, 16, 2);  // I2C address 0x27 or 0x3F; check with scanner

void setup() {
  Serial.begin(115200);
  Wire.begin();  // SDA PB7/D14, SCL PB6/D15
  lcd.init();
  lcd.backlight();
  lcd.clear();
  dht.begin();
  delay(2000);
}

void loop() {
  float h = dht.readHumidity();
  float t = dht.readTemperature();

  if (isnan(h) || isnan(t)) {
    Serial.println("Failed to read from DHT sensor!");
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("DHT Read Fail");
    delay(2000);
    return;
  }

  Serial.print("Humidity: "); Serial.print(h);
  Serial.print(" %\tTemperature: "); Serial.print(t); Serial.println(" *C");

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(t, 1);
  lcd.print(" C");

  lcd.setCursor(0, 1);
  lcd.print("RH: ");
  lcd.print(h, 1);
  lcd.print(" %");

  delay(2000);  // DHT11 needs 2s min
}