ESP8266 NodeMCU Access Point (AP) for Web Server With DT11 Temperature Sensor and Printing Temperature & Humidity in Browser

1x ESP 8266 Nodemcu :




1x DHT11 :

1x breadboard :. :

Few jumpers :

From my previous instructables i am gonna modify the webserver code of this instructables :

https://www.instructables.com/id/ESP8266-Nodemcu-T...

And turn it into access point webserver code.


Please copy the code provided below :

#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";
const char* password = "password";

#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(






ESP8266 DHT Server

Temperature
%TEMPERATURE%
°C

Humidity
%HUMIDITY%
%

)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);
}
}
}



Before you upload the code make sure you put following things :

const char* ssid = "ESP8266"; // whatever ssid of wifi you want
const char* password = "password"; //pass to connect to above ssid



Set The ESP8266 as an Access Point :
To set esp8266 as an access point we will be using softAP command as shown below ; to create a access point.

WiFi.softAP(ssid, password);
There are also other optional parameters you can pass to the softAP() method. Here’s all the parameters:

If youbopen the serial monitor you can see the IP of access point. Which is done by following part of the code .

IPAddress IP = WiFi.softAPIP();
Serial.print("AP IP address: ");
Serial.println(IP);
By default Ip address is : 192.168.4.1