ESP8266-LEDMatrix-WiFiDisplay

ESP8266 LED Matrix WiFi Display

This project displays text on a MAX7219-based LED matrix using an ESP8266 module (e.g., NodeMCU). It allows users to control the displayed text and brightness level via a browser-based interface hosted by the ESP8266. A captive portal is automatically launched if no WiFi credentials are found.

Sketch and Code

💡 The main sketch is in ESP8266_LED_MATRIX_TEXT_DISPLAY.ino, but you can also view the syntax-highlighted C++ version here: LEDMatrix_WiFi_Code.cpp

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🔧 Features

• ESP8266 auto-connects to saved WiFi or creates an access point if none is found.
• Web-based interface for:
  • Sending custom text to the LED matrix
  • Adjusting LED brightness
• Clean, styled HTML interface
• IP address displayed on the LED matrix after successful WiFi connection
• Optional WiFi reset for testing or clean startup

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🧰 Requirements

• Board: ESP8266 (NodeMCU, Wemos D1 Mini, etc.)
• Display: MAX7219-based 8x32 LED Matrix (FC16_HW)
• Libraries:
  • MD_MAX72xx
  • WiFiManager
• IDE: Arduino IDE

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🔌 Wiring

You're using a MAX7219-based 8x32 LED Matrix Display (i.e., 4 x 8x8 modules in series). Connect it to your ESP8266 (NodeMCU or similar) as follows:

LED Matrix Pin	ESP8266 Pin	NodeMCU Label
VCC	3.3V	3V3
GND	GND	G
DIN (Data In)	GPIO13	D7
CS (Load)	GPIO15	D8
CLK (Clock)	GPIO14	D5

💡 Tip: These modules use the FC-16 layout, which matches well with the MD_MAX72xx::FC16_HW hardware setting in code.

⚠️ Note: Although it may work on 3.3V, for brighter and more stable display (especially for 8x32 or larger), it's recommended to use 5V power with a logic level shifter on data lines.

📱 How It Works

1. On boot, ESP8266 tries to connect to saved WiFi credentials.
2. If no WiFi is found (or reset is triggered), it creates a captive portal via WiFiManager.
3. User connects to the ESP8266 access point ESP8266_LED_AP.
4. The user selects and connects to a WiFi network.
5. After a successful connection, the ESP8266 reboots and displays its local IP on the LED matrix.
6. Enter that IP in your browser to open the control interface.

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🚀 Getting Started

1. Install the required libraries via Arduino Library Manager or download from the links above:

   • MD_MAX72xx
   • WiFiManager

2. Connect your hardware:

   • Use the wiring chart from the 🔌 Wiring section above.

3. Open the ESP8266_LED_MATRIX_TEXT_DISPLAY.ino file in the Arduino IDE.

4. Select the correct board (NodeMCU 1.0, Wemos D1 Mini, or other ESP8266), port, and upload speed (typically 115200).

5. Flash or Upload the sketch to your ESP8266.

6. On first boot, WiFi credentials are cleared using:

   wifiManager.resetSettings();  // Clears saved WiFi
   

7. The ESP8266 creates a WiFi access point named: ESP8266_LED_AP

8. Connect to this AP using your phone or computer.

9. A captive portal will appear. If it doesn't, open your browser and visit 192.168.4.1.

10. Choose your WiFi network from the list and enter the password.

11. After successful connection, the ESP8266 will reboot and display the assigned IP address on the LED matrix.

12. Open the shown IP address in a web browser to:

• ✅ Send a scrolling text message

• 💡 Adjust brightness using a slider

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🖼️ Setup Screenshots

📲 Step 1: Connect to ESP8266_LED_AP

After uploading the code, power the ESP8266. It will create a WiFi hotspot named ESP8266_LED_AP.
Connect to this network using your phone or laptop.

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📶 Step 2: Select WiFi & Enter Password

Once connected, the WiFiManager captive portal will appear.
Select your WiFi network from the list and enter its password.

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🌐 Step 3: Access Web Interface to Control Display

After successful WiFi connection, the ESP8266 will reboot and display its IP address 192.168.x.x on the LED matrix.
Enter this IP address into your browser to open the control panel.

Here you can:

• ✍️ Enter a scrolling message
• 💡 Adjust brightness using the slider

🌐 Web Interface Details

Once connected to your WiFi:

• 💬 Send Text: Type a message and click "Send" to display it as scrolling text.
• 💡 Adjust Brightness: Use the slider to control LED brightness (range: 0–15).
• 📟 The interface is mobile and desktop friendly.

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🔁 WiFi Reset Behavior (Optional)

By default, the following line in setup() clears any previously saved WiFi credentials every time the ESP8266 boots:

wifiManager.resetSettings();  // 🔥 This erases saved WiFi credentials on each boot

• This is useful during testing or the first-time setup, ensuring the device always launches in Access Point mode for easy configuration.

✅ Keep WiFi Saved Across Reboots :-

• If you'd like your ESP8266 to remember the connected WiFi after rebooting (recommended for regular use):

1. Comment out or remove the reset line in the setup() function:

// wifiManager.resetSettings();  // ❌ Now credentials will persist after reboot

2. Now the device will automatically reconnect to the last known WiFi network every time it powers on — without asking the user to reconfigure.

3. If you ever want to manually clear the saved credentials later, you can:

• Re-enable the reset line temporarily.

• Or trigger a reset in code with:

WiFiManager wm;
wm.resetSettings();  // Call this once, then remove or comment it again

⚠️ Note: Keeping the reset line enabled will force reconfiguration every time the device restarts, which is not ideal for long-term or headless deployment.

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🛡️ Security

• This project does not expose WiFi credentials to the internet.

• All communications are handled locally using HTTP.

• The reset mechanism ensures no previous credentials persist unintentionally.

• Suitable for testing, DIY smart signage, or educational demos.

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📄 License

MIT License

Let me know if you'd like to:

• Add setup GIFs or extra screenshots
• Include platform badges (ESP8266, Arduino IDE, MIT License, etc.)
• Convert this for GitHub Pages or documentation site integration