📡 LoRa8266T - OTA Wireless Telemetry System

A secure, long-range wireless communication system using ESP8266 and LoRa SX1278 modules with military-grade AES-128 encryption

Features • Hardware • Installation • Usage • Documentation

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🌟 Features

🚀 Performance Long Range Communication: Up to 2km line-of-sight using LoRa 433MHz Fast Data Rate: ~5.5kbps at SF7 Low Latency: Real-time message transmission Signal Monitoring: Built-in RSSI feedback

🔒 Security AES-128 CBC Encryption: Military-grade security PKCS7 Padding: Industry-standard block cipher padding Message Counter: Replay attack prevention XOR Fallback: Lightweight encryption alternative

✨ Additional Capabilities

• 📱 Serial Interface: Easy debugging and message input via UART
• 🔌 Multi-MCU Support: ESP8266, ESP32, Arduino Nano/Uno compatible
• ⚡ OTA Ready: Over-The-Air update capability
• 🎯 Plug & Play: Simple serial communication for other MCUs

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🛠️ Hardware

Core Components

Component	Specification	Quantity
ESP8266	NodeMCU / Wemos D1 Mini	2+
LoRa SX1278	433MHz Module	2+
Jumper Wires	Male-to-Female	8 per unit
Power Supply	3.3V (min 500mA)	1 per unit

Optional Components

• Breadboard for prototyping
• External antenna for extended range
• Level shifter (for 5V Arduino boards)

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🔌 Wiring Diagram

ESP8266 Configuration

ESP8266 GPIO	SX1278 Pin	Description
GPIO15(D8)	NSS/CS	Chip Select
GPIO16(D0)	RST	Reset
GPIO5(D1)	DIO0	Interrupt
GPIO14(D5)	SCK	SPI Clock
GPIO13(D7)	MOSI	SPI Data Out
GPIO12(D6)	MISO	SPI Data In
3.3V	VCC	Power Supply
GND	GND	Ground

Alternative MCU Configurations

ESP32 Configuration

Default Configuration

ESP32 GPIO	SX1278 Pin	Description
GPIO5	NSS/CS	Chip Select
GPIO14	RST	Reset
GPIO2	DIO0	Interrupt
GPIO18	SCK	SPI Clock
GPIO23	MOSI	SPI Data Out
GPIO19	MISO	SPI Data In
3.3V	VCC	Power
GND	GND	Ground

Alternative Configuration

ESP32 GPIO	SX1278 Pin
GPIO15	NSS/CS
GPIO4	RST
GPIO26	DIO0

Arduino Nano/Uno Configuration

Arduino Pin	SX1278 Pin	Description
D10	NSS/CS	Chip Select
D9	RST	Reset
D2	DIO0	Interrupt (INT0)
D13	SCK	SPI Clock
D11	MOSI	SPI Data Out
D12	MISO	SPI Data In
3.3V	VCC	Power
GND	GND	Ground

⚠️ Important: Arduino boards are 5V devices. Use the 3.3V output pin for LoRa power supply!

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📥 Installation

1️⃣ Arduino IDE Setup

# Add ESP8266 Board Package
# File → Preferences → Additional Board Manager URLs:
http://arduino.esp8266.com/stable/package_esp8266com_index.json

2️⃣ Install Required Libraries

Navigate to Sketch → Include Library → Manage Libraries and install:

• LoRa by Sandeep Mistry
• AESLib by DavyLandman

3️⃣ Clone Repository

git clone https://github.com/roboticist-blip/LoRa8266T.git
cd LoRa8266T

4️⃣ Upload Firmware

1. Open LoRa8266T.ino in Arduino IDE
2. Select your board: Tools → Board → ESP8266 Boards → NodeMCU 1.0
3. Select COM port: Tools → Port
4. Click Upload ⬆️

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🚀 Usage

Quick Start

1. Power up both ESP8266 + LoRa modules
2. Open Serial Monitor at 9600 baud
3. Type message and press Enter
4. Watch magic happen ✨

Example Output

ESP8266 LoRa Interface with AES Encryption Starting...
LoRa Ready with AES Encryption!

TX: 0:Hello World (Encrypted)
RX: 1:Hello back! (RSSI: -45)
TX: 2:Testing secure comms
RX: 3:Roger that! (RSSI: -52)

Message Format

• TX: Transmitted message with counter
• RX: Received message with RSSI (signal strength)
• RSSI Values: -30 to -60 (Excellent), -60 to -90 (Good), < -90 (Poor)

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⚙️ Configuration

LoRa Parameters

#define LORA_FREQUENCY 433E6          // 433 MHz (Europe/Asia)
#define LORA_SYNC_WORD 0x12           // Network ID
#define LORA_SPREADING_FACTOR 7       // 7-12 (higher = longer range)
#define LORA_BANDWIDTH 125E3          // 125 kHz
#define LORA_TX_POWER 17              // dBm (2-20)

Regional Frequency Bands

Region	Frequency	Legal Status
Europe/Asia	433 MHz	ISM Band ✅
North America	915 MHz	ISM Band ✅
Europe	868 MHz	ISM Band ✅

AES Encryption Key

uint8_t aes_key[AES_KEY_SIZE] = {
    0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6,
    0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C
};

⚠️ Security Warning: Change the default key for production use!

Performance Tuning

For Maximum Range:

#define LORA_SPREADING_FACTOR 12      // Slower but longer range
#define LORA_TX_POWER 20              // Maximum power

For Maximum Speed:

#define LORA_SPREADING_FACTOR 7       // Faster transmission
#define LORA_BANDWIDTH 250E3          // Wider bandwidth

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🔒 Security Features

Encryption Pipeline

Plaintext → AES-128 CBC → PKCS7 Padding → LoRa Transmission

Security Components

1. AES-128 CBC: Symmetric encryption with 128-bit key
2. Initialization Vector (IV): Randomized per message
3. Message Counter: Monotonically increasing sequence
4. PKCS7 Padding: Ensures block alignment

Attack Mitigation

✅ Replay Attack: Prevented by message counter
✅ Man-in-the-Middle: Protected by AES encryption
✅ Eavesdropping: Encrypted transmission
⚠️ Key Distribution: Manual key sharing required

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🐛 Troubleshooting

Common Issues

Problem	Solution
❌ LoRa init failed	• Check wiring connections • Verify 3.3V power supply • Test with multimeter
📡 No messages received	• Match frequency on both devices • Verify sync word (0x12) • Check antenna connection
🔓 Decryption failed	• Ensure identical AES keys • Verify both devices running same code
📉 Poor range	• Adjust antenna position • Increase TX power • Use higher spreading factor
💡 ESP8266 won't boot	• Check GPIO15 not floating • Verify GPIO0/GPIO2 states • Test power supply

Debug Mode

Enable detailed logging:

#define DEBUG_MODE 1

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📊 Technical Specifications

Parameter	Value
Range	Up to 2km (line-of-sight)
Data Rate	~5.5 kbps @ SF7
Frequency	433 MHz (configurable)
Encryption	AES-128 CBC
Power Consumption	~100mA TX, ~15mA RX
Operating Voltage	3.3V
Interface	UART (9600 baud)

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📚 Documentation

File Structure

LoRa8266T/
├── LoRa8266T.ino          # Main firmware
├── docs/
│   ├── wiring_diagram.png # Connection guide
│   └── LICENSE            # MIT License
└── README.md              # This file

Pin Mapping Reference

View Complete Pin Configurations

ESP8266 Code Example

#define SS_PIN 15      // GPIO15
#define RST_PIN 16     // GPIO16
#define DIO0_PIN 5     // GPIO5

Alternative ESP8266 Pins

#define SS_PIN 4       // GPIO4 (D2)
#define RST_PIN 0      // GPIO0 (D3)
#define DIO0_PIN 2     // GPIO2 (D4)

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🤝 Contributing

We welcome contributions! Here's how you can help:

1. 🍴 Fork the repository
2. 🌿 Create your feature branch: git checkout -b feature/amazing-feature
3. 💾 Commit your changes: git commit -m 'Add amazing feature'
4. 📤 Push to the branch: git push origin feature/amazing-feature
5. 🎉 Open a Pull Request

Development Guidelines

• Follow existing code style
• Test on real hardware before submitting
• Update documentation for new features
• Add comments for complex logic

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📜 License

This project is licensed under the MIT License - see the LICENSE file for details.

What This Means

✅ Commercial use
✅ Modification
✅ Distribution
✅ Private use

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🙏 Acknowledgments

• Sandeep Mistry - LoRa Library
• DavyLandman - AESLib
• ESP8266 Community - Hardware support and documentation

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⚖️ Legal Disclaimer

⚠️ Important Notices:

• This project is for educational and experimental purposes
• Ensure compliance with local radio regulations when using LoRa frequencies
• The default AES key is for demonstration only
• Always use your own secure key in production
• Respect ISM band regulations in your region
• Maximum transmission power may be legally restricted

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🌐 Connect & Support

⭐ Star this repository if you find it useful!

Questions? Open an issue
Ideas? Start a discussion

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Made with ❤️ for the IoT Community

Built with ESP8266 • Secured with AES-128 • Powered by LoRa