Hello friends,
this topic is about sending data from an ESP32 to the application via WiFi in real time. To send the data we will use the Serial Monitor.
-
We will use and adapt the codes on this website:
https://circuits4you.com/2018/11/20/web-server-on-esp32-how-to-update-and-display-sensor-values/ -
It uses Ajax: AJAX is a technique for creating fast and dynamic web pages.
-
We could send random numbers automatically, also send increased numbers, ... but we will send the text that we write in the Serial Monitor.
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Here the code in file ESP32_realtime.ino
/*
* ESP32 AJAX Demo
* Updates and Gets data from webpage without page refresh
* https://circuits4you.com
*/
#include <WiFi.h>
#include <WiFiClient.h>
#include <WebServer.h>
#include "index.h" //Web page header file
WebServer server(80);
//Enter your SSID and PASSWORD
const char* ssid = "YOUR_NETWORK";
const char* password = "YOUR_PASSWORD";
char caracter = '0';
String texto = "";
String texto_send = "";
//===============================================================
// This routine is executed when you open its IP in browser
//===============================================================
void handleRoot() {
String s = MAIN_page; //Read HTML contents
server.send(200, "text/html", s); //Send web page
}
void handleADC() {
// int a = 0;
// a = analogRead(A0); // ORIGINAL CODE
// a = random(1,1023); // RANDOM NUMBER
// a = a + 1; // INCREASE
// if (a >= 1024){a = 0;}
// String adcValue = String(a);
String adcValue = texto_send; // SEND TEXT FROM SERIAL MONITOR.
server.send(200, "text/plane", adcValue); //Send ADC value only to client ajax request
}
//===============================================================
// Setup
//===============================================================
void setup(void){
Serial.begin(115200);
Serial.println();
Serial.println("Booting Sketch...");
/*
//ESP32 As access point
WiFi.mode(WIFI_AP); //Access Point mode
WiFi.softAP(ssid, password);
*/
//ESP32 connects to your wifi -----------------------------------
WiFi.mode(WIFI_STA); //Connectto your wifi
WiFi.begin(ssid, password);
Serial.println("Connecting to ");
Serial.print(ssid);
//Wait for WiFi to connect
while(WiFi.waitForConnectResult() != WL_CONNECTED){
Serial.print(".");
}
//If connection successful show IP address in serial monitor
Serial.println("");
Serial.print("Connected to ");
Serial.println(ssid);
Serial.print("IP address: ");
Serial.println(WiFi.localIP()); //IP address assigned to your ESP
//----------------------------------------------------------------
server.on("/", handleRoot); //This is display page
server.on("/readADC", handleADC);//To get update of ADC Value only
server.begin(); //Start server
Serial.println("HTTP server started");
}
//===============================================================
// This routine is executed when you open its IP in browser
//===============================================================
void loop(void){
server.handleClient();
//////////////// TEXT FROM SERIAL MONITOR ////////////
if (Serial.available() > 0) { // ¿Hay algún caracter?
caracter = Serial.read(); // Toma el caracter
texto += caracter;
if (caracter == '\n') {
texto_send = texto;
Serial.println("Write a text in Serial Monitor and 'Send'");
Serial.print(texto);
texto = "";
}
}
/////////////////////////////////////////////////////
}
- The code also needs to include another file: index.h
