DHT11/DHT22 Temperature and Humidity Web Server(AP)

Code

/*********

  Rui Santos

  Complete project details at https://randomnerdtutorials.com/esp8266-nodemcu-access-point-ap-web-server/

  Permission is hereby granted, free of charge, to any person obtaining a copy

  of this software and associated documentation files.

  The above copyright notice and this permission notice shall be included in all

  copies or substantial portions of the Software.

*********/

// Import required libraries

#include <Arduino.h>

#include <ESP8266WiFi.h>

#include <Hash.h>

#include <ESPAsyncTCP.h>

#include <ESPAsyncWebServer.h>

#include <Adafruit_Sensor.h>

#include <DHT.h>

const char* ssid     = "ESP8266-Access-Point";

const char* password = "123456789";

#define DHTPIN 5     // Digital pin connected to the DHT sensor

// Uncomment the type of sensor in use:

//#define DHTTYPE    DHT11     // DHT 11

#define DHTTYPE    DHT22     // DHT 22 (AM2302)

//#define DHTTYPE    DHT21     // DHT 21 (AM2301)

DHT dht(DHTPIN, DHTTYPE);

// current temperature & humidity, updated in loop()

float t = 0.0;

float h = 0.0;

// Create AsyncWebServer object on port 80

AsyncWebServer server(80);

// Generally, you should use "unsigned long" for variables that hold time

// The value will quickly become too large for an int to store

unsigned long previousMillis = 0;    // will store last time DHT was updated

// Updates DHT readings every 10 seconds

const long interval = 10000;

const char index_html[] PROGMEM = R"rawliteral(

<!DOCTYPE HTML><html>

<head>

  <meta name="viewport" content="width=device-width, initial-scale=1">

  <style>

    html {

     font-family: Arial;

     display: inline-block;

     margin: 0px auto;

     text-align: center;

    h2 { font-size: 3.0rem; }

    p { font-size: 3.0rem; }

    .units { font-size: 1.2rem; }

    .dht-labels{

      font-size: 1.5rem;

      vertical-align:middle;

      padding-bottom: 15px;

  </style>

</head>

<body>

  <h2>ESP8266 DHT Server</h2>

<p>

    <span class="dht-labels">Temperature</span>

    <span id="temperature">%TEMPERATURE%</span>

    <sup class="units">&deg;C</sup>

  </p>

<p>

    <span class="dht-labels">Humidity</span>

    <span id="humidity">%HUMIDITY%</span>

    <sup class="units">%</sup>

  </p>

</body>

<script>

setInterval(function ( ) {

  var xhttp = new XMLHttpRequest();

  xhttp.onreadystatechange = function() {

    if (this.readyState == 4 && this.status == 200) {

      document.getElementById("temperature").innerHTML = this.responseText;

};

  xhttp.open("GET", "/temperature", true);

  xhttp.send();

}, 10000 ) ;

setInterval(function ( ) {

  var xhttp = new XMLHttpRequest();

  xhttp.onreadystatechange = function() {

    if (this.readyState == 4 && this.status == 200) {

      document.getElementById("humidity").innerHTML = this.responseText;

};

  xhttp.open("GET", "/humidity", true);

  xhttp.send();

}, 10000 ) ;

</script>

</html>)rawliteral";

// Replaces placeholder with DHT values

String processor(const String& var){

  //Serial.println(var);

  if(var == "TEMPERATURE"){

    return String(t);

  else if(var == "HUMIDITY"){

    return String(h);

  return String();

void setup(){

  // Serial port for debugging purposes

  Serial.begin(115200);

  dht.begin();

  Serial.print("Setting AP (Access Point)…");

  // Remove the password parameter, if you want the AP (Access Point) to be open

  WiFi.softAP(ssid, password);

  IPAddress IP = WiFi.softAPIP();

  Serial.print("AP IP address: ");

  Serial.println(IP);

  // Print ESP8266 Local IP Address

  Serial.println(WiFi.localIP());

  // Route for root / web page

  server.on("/", HTTP_GET, [](AsyncWebServerRequest *request){

    request->send_P(200, "text/html", index_html, processor);

});

  server.on("/temperature", HTTP_GET, [](AsyncWebServerRequest *request){

    request->send_P(200, "text/plain", String(t).c_str());

});

  server.on("/humidity", HTTP_GET, [](AsyncWebServerRequest *request){

    request->send_P(200, "text/plain", String(h).c_str());

});

  // Start server

  server.begin();

void loop(){

  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {

    // save the last time you updated the DHT values

    previousMillis = currentMillis;

    // Read temperature as Celsius (the default)

    float newT = dht.readTemperature();

    // Read temperature as Fahrenheit (isFahrenheit = true)

    //float newT = dht.readTemperature(true);

    // if temperature read failed, don't change t value

    if (isnan(newT)) {

      Serial.println("Failed to read from DHT sensor!");

    else {

      t = newT;

      Serial.println(t);

    // Read Humidity

    float newH = dht.readHumidity();

    // if humidity read failed, don't change h value

    if (isnan(newH)) {

      Serial.println("Failed to read from DHT sensor!");

    else {

      h = newH;

      Serial.println(h);

อ้างอิง

https://randomnerdtutorials.com/esp8266-nodemcu-access-point-ap-web-server/

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