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Using Web Browser

Updates with the Web Browser UPDATED w/v1.1.5

AutoConnect features a built-in OTA function to update ESP module firmware. You can easily make the Sketch that equips OTA and able to operate with the AutoConnect menu. As the AutoConnectOTA class, which is compliant with OTA updates using a web browser as described in the ESP8266 Arduino Core documentation.

You will be able to import the AutoConnectOTA class into your sketch just by specifying AutoConnectConfig::ota. By incorporating the AutoConnectOTA class into your Sketch, you can have an OTA updating feature which able to updating binary sketch from the AutoConnect menu.

The AutoConnectOTA feature is implemented based on the Updater class of the ESP8266 arduino core library. Its Updater class is also supported by the ESP32 Arduino core, so you can commonly import AutoConnectOTA into the Sketch without being aware of the differences between ESP8266 and ESP32 modules.

Limitation of AutoConnectOTA with authentication

AutoConnectOTA does not support authentication in v1.1.5 yet. It is planned for inclusion in AutoConnect v1.2.0, which will support HTTP authentication.

How to embed AutoConnectOTA in your sketch

To embed the AutoConnectOTA class into your sketch, basically follow these steps:

  1. Include ESP8266WiFi.h, ESP8266WebServer.h and AutoConnect.h as usual.1
  2. Declare an ESP8266WebServer object. It's optional. (as WebServer for ESP32)
  3. Declare an AutoConnect object, with an argument as ESP8266WebServer if separate the declarations.
  4. Declare an AutoConnectConfig object.
  5. Declare an AutoConnectAux object for your sketch own if needed.
  6. Perform the following procedure steps in the setup() function:
    1. Set AutoConnectConfig::ota to AC_OTA_BUILTIN and configure AutoConnect.
    2. Load the AutoConnectAux pages declared in step #4 for your application.
    3. Join these pages to AutoConnect.
    4. Invokes AutoConnect::begin function.
  7. Invokes AutoConnect::handleClient function in the loop().
#include <ESP8266WiFi.h>            // Step #1
#include <ESP8266WebServer.h>       // Step #1
#include <AutoConnect.h>            // Step #1

ESP8266WebServer  server;           // Step #2
AutoConnect       portal(server);   // Step #3
AutoConnectConfig config;           // Step #4
AutoConnectAux    hello;            // Step #5

static const char HELLO_PAGE[] PROGMEM = R"(
{ "title": "Hello world", "uri": "/", "menu": true, "element": [
    { "name": "caption", "type": "ACText", "value": "<h2>Hello, world</h2>",  "style": "text-align:center;color:#2f4f4f;padding:10px;" },
    { "name": "content", "type": "ACText", "value": "In this page, place the custom web page handled by the Sketch application." } ]
)";                                 // Step #5

void setup() {
  config.ota = AC_OTA_BUILTIN;      // Step #6.a
  portal.config(config);            // Step #6.a
  hello.load(HELLO_PAGE);           // Step #6.b
  portal.join({ hello });           // Step #6.c
  portal.begin();                   // Step #6.d

void loop() {
  portal.handleClient();            // Step #7

How LED ticking during updates

AutoConnectOTA applies LED ticking during updates automatically. The destination LED port and ticker drive depends on AutoConnectConfig::tickerPort and AutoConnectConfig::tickerOn specifying.

The AutoConnectOTA activates the ticker constantly regardless of the AutoConnectConfig::ticker value. If you want to stop the ticker output to GPIO during updates, give 0xff to AutoConnectConfig::tickerPort.

AutoConnectOTA allocation URI

AutoConnectOTA has implemented using AutoConnectAUX. So it occupies two URIs by default. An update operation page is assigned to AUTOCONNECT_URI_UPDATE and the binary file uploader for the update is assigned to AUTOCONNECT_URI_UPDATE_ACT. These symbols are defined in the AutoConnectDefs.h header file as follows:

#define AUTOCONNECT_URI             "/_ac"

Therefore, the normal Sketch that imports AutoConnectOTA while keeping the default, you cannot use the two URIs /_ac/update and /_ac/update_act for your specific. If you want to use the URIs for any purpose other than AutoConnectOTA, you need to override the AutoConnectDefs.h definition at compile time. It can be overwritten by giving the build flags for platformio.ini as follows with the PlatformIO environment for example.

build_flags = 

Timing of AutoConnectOTA instantiation

It will be born during AutoConnect::handleClient process. AutoConnect will evaluate the enabled state of AutoConnectConfig::ota each time the handleClient is executed, and if OTA is enabled then it creates an AutoConnectAux internally and assigns it to the update page. At this time, AutoConnectOTA is also instantiated together. The generated AUX page containing AutoConnectOTA is bound to AutoConnect inside the AutoConnect::handleClient process.

If you want to attach AutoConnectOTA dynamically with an external trigger, you can sketch like this:
This sketch imports the OTA update feature with an external switch assigned to the GPIO pin. While the trigger not occurs, AutoConnect OTA will not be imported into Sketch and will not appear on the menu list.

#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <AutoConnect.h>

#define TRIGGER 4   // pin assigned to external trigger switch

AutoConnect portal;
AutoConnectConfig config;

void setup() {
  pinMode(TRIGGER, INPUT);

void loop() {
  if (digitalRead(TRIGGER) == HIGH) {
    config.ota = AC_OTA_BUILTIN;

AutoConnectOTA cannot detach dynamically

Once imported, AutoConnectOTA cannot be removed from the Sketch. It can be only excluded from the menu by overriding AutoConnectConfig::menuItems. In this case, the AutoConnectOTA instance remains as a residue.

How to make the binary sketch

Binary sketch files for updating can be retrieved using the Arduino IDE. Open the Sketch menu and select the Export compiled Binary, then starts compilation.

When the compilation is complete, a binary sketch will save with the extension .bin in the same folder as the Sketch.

OTA updates w/browser without using AutoConnectOTA

The legacy OTA method based on ESP8266HTTPUpdateServer without AutoConnectOTA is still valid. To embed the ESP8266HTTPUpdateServer class with AutoConnect into your sketch, basically follow these steps:

  1. Include ESP8266HTTPUpdateServer.h, also WiFiClient.h, in addition to the usual directives as ESP8266WebServer.h and AutoConnect.h.2
  2. Declare an ESP8266WebServer object. (In ESP32, as WebServer)
  3. Declare an ESP8266HTTPUpdateServer object.
  4. Declare an AutoConnect object with an ESP8266WebServer object as an argument.
  5. Declare an AutoConnectAux object for the update operation page.
  6. Assign /update to the URI of the update dialog page.
  7. Assign any title as the AutoConnect menu for the update dialog page.
  8. Declare additional AutoConnectAux pages for your application intention if needed.
  9. Perform the following procedure steps in the setup() function:
    1. Invokes ESP8288HTTPUpdateServer::setup function, specifies the USERNAME and the PASSWORD as needed.
    2. Load the AutoConnectAux pages declared in step #8 for your application. (Except the update dialog page)
    3. Join these pages to AutoConnect along with the update dialog page declared in step #5.
    4. Invokes AutoConnect::begin function.
  10. Invokes AutoConnect::handleClient function in the loop().
#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <ESP8266HTTPUpdateServer.h>    // Step #1
#include <WiFiClient.h>                 // Step #1
#include <AutoConnect.h>

static const char HELLO_PAGE[] PROGMEM = R"(
{ "title": "Hello world", "uri": "/", "menu": true, "element": [
    { "name": "caption", "type": "ACText", "value": "<h2>Hello, world</h2>",  "style": "text-align:center;color:#2f4f4f;padding:10px;" },
    { "name": "content", "type": "ACText", "value": "In this page, place the custom web page handled by the Sketch application." } ]

ESP8266WebServer httpServer;                // Step #2
ESP8266HTTPUpdateServer httpUpdate;         // Step #3
AutoConnect portal(httpServer);             // Step #4
AutoConnectAux update("/update", "UPDATE"); // Step #5, #6, #7
AutoConnectAux hello;                       // Step #8

void setup() {
  httpUpdate.setup(&httpServer, "USERNAME", "PASSWORD"); // Step #9.a
  hello.load(HELLO_PAGE);                   // Step #9.b
  portal.join({ hello, update });           // Step #9.c
  portal.begin();                           // Step #9.d

void loop() {
  portal.handleClient();                    // Step #10

Regular file uploading using AutoConnectOTA ENHANCED w/v1.2.0

The built-in OTA update feature can update the firmware as well as upload regular files placed in the file system on the ESP module. It allows a regular file is uploaded via OTA using the Update of AutoConnect menu without adding a particular custom Web page that contains AutoConnectFile. This utilization is useful for the operation of transferring the JSON document of the custom web page definition, the external parameter file of your sketch, and so on into the target ESP module via OTA.

The built-in OTA update feature determines where to save the uploaded file according to the filename pattern. By default, a filename with ends a .bin extension is subject to firmware updates. A file that has another extensions will be saved as a regular to LittleFS (or SPIFFS) in the flash.

The filename extension that should be treated as the firmware is defined as the AUTOCONNECT_UPLOAD_ASFIRMWARE macro in AutoConnectDefs.h header file of the library source code. When dealing with another extensions for the updating file as firmware change this macro definition.


Specify with the PlatformIO

AUTOCONNECT_UPLOAD_ASFIRMWARE pattern will be embedded into the binary sketch is determined at compile time. The PlatformIO build system allows you to change the pattern of the file extension for each project without modifying the library source code.


Use a regular expression to specify the file extension

By default, you can specify only one file extension to be treated as firmware in OTA updates. However, you can specify the file extension as a regular expression, but it consumes a lot of memory.

If the file extension pattern contains a regular expression, you need to enable the flag of AUTOCONNECT_UPLOAD_ASFIRMWARE_USE_REGEXP in AutoConnectDefs.h. Also, the AUTOCONNECT_UPLOAD_ASFIRMWARE definition as a regular expression is treated as a replacement string for the #define directive for C++ preprocessor, so the backslash must be escaped.

  1. For ESP32, change the following items:

    • Change the include directives appropriately for the ESP32 environment.
    • Change ESP8266WebServer to WebServer.

  2. The AutoConnect library provides an implementation of the HTTPUpdateServer class that ported from ESP8266HTTPUpdateServer class for ESP32 intention. It is contained the WebUpdate under the examples folder.