📡 Air Bytes

Offline, encrypted, GPS-tagged peer-to-peer messaging over LoRa — no internet required.

Built for the Heltec WiFi LoRa 32 V3 (ESP32-S3) using RadioLib and the onboard SSD1306 OLED.

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Features

• 🔒 XOR-encrypted text messages
• 📍 GPS coordinates attached to every message
• 📟 Live OLED display with inbox + compose UI
• 📶 LoRa @ 865 MHz, SF9 (India ISM band)
• 🔋 Two-button operation — no touchscreen needed

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Hardware Required

Component	Details
Heltec WiFi LoRa 32 V3	× 2 (one per node)
GPS Module	NEO-6M or NEO-8M
Tactile Button	External SPACE button

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Wiring

GPS Module	Heltec V3 Pin
TX	GPIO 4
VCC	3.3V
GND	GND

SPACE Button	Heltec V3 Pin
Leg 1	GPIO 45
Leg 2	GND

Everything else (OLED, LoRa, PRG button) is already onboard.

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Button Controls

Button	Action
PRG short press	Backspace
PRG long press	Send message
SPACE press	Add a space

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Setup (Arduino IDE)

1. Add ESP32 board support

File → Preferences → paste this URL: https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_index.json Then: Tools → Boards Manager → install esp32 by Espressif Systems

2. Install libraries via Tools → Manage Libraries:

• RadioLib — Jan Gromeš
• Adafruit SSD1306 — Adafruit
• Adafruit GFX Library — Adafruit
• TinyGPS++ — Mikal Hart

3. Select board

Tools → Board → Heltec WiFi LoRa 32(V3)

4. Set Node ID in the sketch before uploading:

#define NODE_ID  0x01   // Node A
#define NODE_ID  0x02   // Node B

5. Upload — hold BOOT button if it fails to connect.

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How It Works

[Node A] → type message → PRG long press
        → XOR encrypt → pack with GPS coords
        → transmit over LoRa @ 865 MHz

[Node B] → receives packet → decrypt → show on OLED
        → displays sender, RSSI, GPS, message text

Inbox holds the last 3 messages. Older messages are overwritten in a circular buffer.

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Configuration

Setting	Location	Default
Node ID	#define NODE_ID	0x01
Encryption key	#define XOR_KEY	"SECRETKEY123"
LoRa frequency	radio.begin(...)	865.0 MHz
Spreading factor	radio.begin(...)	SF9

Both nodes must use the same XOR_KEY to communicate.

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