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](https://arduino-esp8266.readthedocs.io/en/latest/ota_updates/readme.html#implementation-overview).
You will be able to import the AutoConnectOTA class into your sketch just by specifying [AutoConnectConfig::ota](apiconfig.md#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](https://arduino-esp8266.readthedocs.io/en/latest/ota_updates/readme.html#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.
!!! info "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.
### <i class="fa fa-edit"></i> 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](apiconfig.md#ota) to **AC_OTA_BUILTIN** and configure AutoConnect.
2. Load the AutoConnectAux pages declared in step #4 for your application.
- Change the include directives appropriately for the ESP32 environment.
- Change ESP8266WebServer to Web.
!!! faq "How LED ticking during updates"
AutoConnectOTA applies LED ticking during updates automatically. The destination LED port and ticker drive depends on [AutoConnectConfig::tickerPort](apiconfig.md#tickerport) and [AutoConnectConfig::tickerOn](apiconfig.md#tickeron) specifying.
**IMPORTANT**
The AutoConnectOTA activates the ticker constantly regardless of the [AutoConnectConfig::ticker](apiconfig.md#ticker) value. If you want to stop the ticker output to GPIO during updates, give `0xff` to [AutoConnectConfig::tickerPort](apiconfig.md#tickerport).
### <i class="fa fa-wrench"></i> 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:
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.
```ini
build_flags =
-DAUTOCONNECT_URI_UPDATE='"/YOURURI"'
-DAUTOCONNECT_URI_UPDATE_ACT='"/YOURURIACT"'
```
### <i class="fa fa-wrench"></i> Timing of AutoConnectOTA instantiation
It will be born during [AutoConnect::handleClient](api.md#handleclient) process. AutoConnect will evaluate the enabled state of [AutoConnectConfig::ota](apiconfig.md#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._
```cpp
#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>
#include <AutoConnect.h>
#define TRIGGER 4 // pin assigned to external trigger switch
Once imported, AutoConnectOTA cannot be removed from the Sketch. It can be only excluded from the menu by overriding [AutoConnectConfig::menuItems](apiconfig.md#menuitems). In this case, the AutoConnectOTA instance remains as a residue.
### <i class="fa fa-wrench"></i> 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.