A simple http server to get temperature and humidity with DHT-11 sensor and esp8266

esp8266-dh11-sensor-wifi-http-server.ino

#include <ESP8266WiFi.h>
#include "DHT.h"

#define DHTTYPE DHT11

const char* ssid = "xxx";
const char* password = "xxx";

WiFiServer server(80);

const int DHTPin = D8;

static char celsiusTemp[7];
static char humidityTemp[7];

DHT dht(DHTPin, DHTTYPE);

bool started = false;

void setup() 
{
  Serial.begin(9600);
  
  delay(10);

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

  Serial.println(WiFi.localIP());
}
  
void loop() 
{
  if (started == false) {
    delay(500);
    dht.begin();
    delay(500);
    started = true;
  }
 
  WiFiClient client = server.available();
  if (!client) {
    return;
  }
  
  while(!client.available()){
    delay(1);
  }

  float h = dht.readHumidity();
  float t = dht.readTemperature();
  if (isnan(h) || isnan(t)) {
    // we can't read the values for some reason
    strcpy(celsiusTemp,"false");
    strcpy(humidityTemp, "false");
  } else {
    float hic = dht.computeHeatIndex(t, h, false);
    dtostrf(hic, 6, 2, celsiusTemp);
    dtostrf(h, 6, 2, humidityTemp);
  }

  // Return JSON result to the client
  client.print("HTTP/1.1 200 OK\r\nContent-Type: application/json\r\n\r\n{\"temp\":");
  client.print(celsiusTemp);
  client.print(", \"humidity\": ");
  client.print(humidityTemp);
  client.println("}");
    
  client.flush();
  delay(1);
}