ESP32-OTA (Over the air) programming

ESP32-OTA (Over the air) programming

Aim:

Turn ON and OFF an LED after Particular delay using OTA web server

Description:

Turn To learn how to connect LED to digital pins of an ESP32 Microcontroller and program to blink an LED using OTA web server.

Hardware required:

ESP32-Microcontroller development board.

Pin connection:

Pin Mapping:

LED	ESP32
LED	I04

Procedure:

1. When you install the ESP32 add-on for the Arduino IDE, it will automatically install the      

    Arduino OTA library.

2. Go to File > Examples > ArduinoOTA > OTAWebUpdater.

3. The following code should load.

#include <WiFi.h>

#include <WiFiClient.h> 

#include <WebServer.h> 

#include <ESPmDNS.h> 

#include <Update.h>

const char* host = "esp32"; const char* ssid = "ssid";

const char* password = "password";

WebServer server(80);

/*

* Login page

*/

const char* loginIndex = "<form name='loginForm'>"

"<table width='20%' bgcolor='A09F9F' align='center'>" 

   "<tr>"

"<td colspan=2>"

"<center><font size=4><b>ESP32 Login Page</b></font></center>" 

"<br>"

"</td>" 

"<br>"

"<br>"

"</tr>"

"<td>Username:</td>"

"<td><input type='text' size=25 name='userid'><br></td>" 

"</tr>"

"<br>"

"<br>"

"<tr>"

"<td>Password:</td>"

"<td><input type='Password' size=25 name='pwd'><br></td>" 

"<br>"

"<br>" 

"</tr>"

"<tr>"

"<td><input type='submit' onclick='check(this.form)' value='Login'></td>" 

"</tr>"

"</table>"

"</form>"

"<script>"

"function check(form)" 

"{"

"if(form.userid.value=='admin' && form.pwd.value=='admin')" 

"{"

"window.open('/serverIndex')" 

"}"

"else" 

 "{"

" alert('Error Password or Username')/*displays error message*/" 

"}"

"}"

"</script>";

/*

* Server Index Page

*/

const char* serverIndex =

"<script src='https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js'></script>" 

"<form method='POST' action='#' enctype='multipart/form-data' id='upload_form'>"

"<input type='file' name='update'>" 

"<input type='submit' value='Update'>"

"</form>"

"<div id='prg'>progress: 0%</div>" 

"<script>" 

"$('form').submit(function(e){" "e.preventDefault();"

"var form = $('#upload_form')[0];" "var data = new FormData(form);" " $.ajax({"

"url: '/update',"

"type: 'POST',"

"data: data," "contentType: false," "processData:false," "xhr: function() {"

"var xhr = new window.XMLHttpRequest();" "xhr.upload.addEventListener('progress', function(evt) {" "if (evt.lengthComputable) {"

"var per = evt.loaded / evt.total;"

"$('#prg').html('progress: ' + Math.round(per*100) + '%');" 

"}"

"}, false);"  

"return xhr;" 

"},"

"success:function(d, s) {" "console.log('success!')" 

"},"

"error: function (a, b, c) {" "}"

"});"

"});"

"</script>";

/*

* setup function

*/

void setup(void) {

Serial.begin(115200);

// Connect to WiFi network

WiFi.begin(ssid, password);

Serial.println("");

// Wait for connection

while (WiFi.status() != WL_CONNECTED) { delay(500);

Serial.print(".");

}

Serial.println(""); Serial.print("Connected to "); Serial.println(ssid); Serial.print("IP address: "); Serial.println(WiFi.localIP());

/*use mdns for host name resolution*/

if (!MDNS.begin(host)) { //http://esp32.local Serial.println("Error setting up MDNS responder!"); 

while (1) {

delay(1000);

}

}

Serial.println("mDNS responder started");

/*return index page which is stored in serverIndex */ server.on("/", HTTP_GET, []() { server.sendHeader("Connection", "close"); 

server.send(200, "text/html", loginIndex);

});

server.on("/serverIndex", HTTP_GET, []() { server.sendHeader("Connection", "close"); server.send(200, "text/html", serverIndex);

});

/*handling uploading firmware file */ 

server.on("/update", HTTP_POST, []() { server.sendHeader("Connection", "close");

server.send(200, "text/plain", (Update.hasError()) ? "FAIL" : "OK"); ESP.restart();

}, []() {

HTTPUpload& upload = server.upload();

if (upload.status == UPLOAD_FILE_START) {

Serial.printf("Update: %s\n", upload.filename.c_str());

if (!Update.begin(UPDATE_SIZE_UNKNOWN)) { //start with max available size

Update.printError(Serial);

}

} else if (upload.status == UPLOAD_FILE_WRITE) {

/* flashing firmware to ESP*/

if (Update.write(upload.buf, upload.currentSize) != upload.currentSize) {

Update.printError(Serial);

}

} else if (upload.status == UPLOAD_FILE_END) {

if (Update.end(true)) { //true to set the size to the current progress

Serial.printf("Update Success: %u\nRebooting...\n", upload.totalSize);

} else {

Update.printError(Serial);

}

}

});

server.begin();

}

void loop(void) { server.handleClient(); delay(1);

}

1. You should change the following lines on the code to include your own network credentials.

Ø  const char* ssid = “ ” ;

Ø  const char* password = “ ” ;

    2.       Upload the above code to ESP32 board. Enter proper network credentials.

    3.       Now select proper board and serial port.

    4.   Once the code is uploaded , open serial monitor select baud rate 115200 and press enable         

          button and then you will get ESP32 IP address.

   8.   Copy the IP address which you obtain from the serial monitor and paste it in your browser.

   9.  Username: admin

          Password: admin

    10. After entering the username and password a new tab should open on the /serverIndex URL.  

          This page allows you to upload a new code to your ESP32. You should upload .bin files.

Preparing the sketch:

    1.  Write a simple program (Blinking of LED) using OTA web server and save it with the name 

           LED_blink and complile it.

     2.      Once the uploading is done go to Sketch<Export compiled binary.

         3.        Then select Sketch<Show sketch folder.

         4.        In this folder two files will be generated .ino and .bin.

         5.        You should upload the .bin file using OTA Web Server.

        6.        In browser on ESP32 OTA Web Updater page , click on choose file button

        7.        Select .bin file and click Update.

        8.        Code will be successfully uploaded.

Output: