Getting Started

Important: Arduino OTA works only after the ESP32 has been flashed once using a USB cable. The initial firmware starts the OTA service and makes the ESP32 discoverable on your local network.

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Project Structure

ESP32_OTA_using_ArduinoIDE/
│
├── ESP32_OTA_ARDUINO_IDE SETUP/
│   └── ESP32_OTA_ARDUINO_IDE SETUP.ino
│
├── ESP32_OTA_ARDUINO_IDE_LED_BLINKING/
│   └── ESP32_OTA_ARDUINO_IDE_LED_BLINKING.ino
├── images/
└── README.md

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Step 1: Upload the Setup Sketch (USB Upload)

Open the following sketch:

ESP32_OTA_ARDUINO_IDE SETUP/
└── ESP32_OTA_ARDUINO_IDE SETUP.ino

Update your Wi-Fi credentials:

const char* ssid = "YOUR_WIFI_NAME";
const char* password = "YOUR_WIFI_PASSWORD";

Connect the ESP32 to your computer using a USB cable and upload this sketch.

This step is mandatory and only needs to be done once.

The setup sketch:

• Connects the ESP32 to Wi-Fi.
• Starts the Arduino OTA service.
• Makes the ESP32 discoverable on your local network.
• Prints the assigned IP address to the Serial Monitor.

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Step 2: Verify the ESP32 is Connected

Open the Serial Monitor at 115200 baud.

You should see output similar to:

Connecting to WiFi...

WiFi Connected

IP Address:
192.168.1.105

Arduino OTA Ready

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Step 3: Select the Network Port

In Arduino IDE, go to:

Tools
    └── Port

After a few seconds, a new Network Port should appear.

Example:

ESP32 at 192.168.1.105

Select this network port.

Important: From this point onward, all firmware uploads will be performed wirelessly over Wi-Fi.

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Step 4: Upload the OTA Test Sketch

Open the OTA test sketch:

ESP32_OTA_ARDUINO_IDE_LED_BLINKING/
└── ESP32_OTA_ARDUINO_IDE_LED_BLINKING.ino

Make sure the Network Port is still selected.

Click Upload.

The Arduino IDE will:

1. Compile the firmware.
2. Send the firmware over Wi-Fi.
3. Flash the ESP32 wirelessly.
4. Restart the ESP32 automatically.

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Step 5: Verify the OTA Update

Once the upload completes:

• The ESP32 restarts automatically.
• The onboard LED begins blinking.
• The Serial Monitor displays the updated firmware output.

This confirms that the OTA update was successful.

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OTA Development Workflow

For all future firmware updates:

1. Modify your code.
2. Select the ESP32 Network Port.
3. Click Upload.
4. Wait for the upload to finish.
5. ESP32 restarts automatically.
6. Verify the updated firmware.

No USB cable is required unless:

• Wi-Fi credentials are changed.
• The OTA setup sketch is erased.
• The ESP32 is factory reset.
• The firmware becomes corrupted and can no longer boot.

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Workflow Summary

USB Upload (One Time)

        │
        ▼

ESP32_OTA_ARDUINO_IDE SETUP.ino

        │
        ▼

ESP32 Connects to Wi-Fi

        │
        ▼

Arduino OTA Service Starts

        │
        ▼

ESP32 Appears in Arduino IDE
(Network Port)

        │
        ▼

Open

ESP32_OTA_ARDUINO_IDE_LED_BLINKING.ino

        │
        ▼

Click Upload

        │
        ▼

Firmware Sent Over Wi-Fi

        │
        ▼

ESP32 Restarts

        │
        ▼

LED Starts Blinking

        │
        ▼

OTA Working Successfully