📡 RANGER-VILLAGE — LoRa Dual Communication System

Wireless text communication between two ESP32 stations using SX1278 LoRa at 433 MHz with an 8×32 LED matrix display.

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🗺️ System Overview

┌─────────────────────────┐                        ┌─────────────────────────┐
│        RANGER           │                        │        VILLAGE          │
│    ESP32 WROOM-32       │◄──── LoRa 433 MHz ────►│    ESP32 WROOM-32D      │
│                         │                        │                         │
│  • Type keyword         │ ──── keyword msg ────► │  • Scrolls response     │
│    in Serial Monitor    │                        │    on 8×32 LED Matrix   │
│                         │                        │                         │
│  • Receives alert msg   │ ◄─── button press ──── │  • Press Button 1 or 2  │
│    in Serial Monitor    │                        │    to send alert        │
└─────────────────────────┘                        └─────────────────────────┘

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🛠️ Hardware Used

Component	Qty	Role
ESP32 WROOM-32	1	RANGER station
ESP32 WROOM-32D	1	VILLAGE station
SX1278 LoRa Module	2	433 MHz wireless link
MAX7219 8×32 LED Matrix	1	Message display at VILLAGE
Push Button	2	Alert triggers at VILLAGE
Jumper Wires	—	All connections
433 MHz Antenna	2	One per LoRa module

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🔌 Circuit Diagram

SX1278 LoRa → ESP32 (Both boards — identical wiring)

SX1278 Pin	ESP32 GPIO	Board Label	Row
VCC	3.3V	3V3	BOTTOM left
GND	GND	GND	TOP
SCK	GPIO 18	18	TOP
MISO	GPIO 19	19	TOP
MOSI	GPIO 23	23	TOP
NSS	GPIO 5	5	TOP
RST	GPIO 14	14	BOTTOM ⚠️
DIO0	GPIO 2	2	TOP

MAX7219 Matrix → ESP32 (VILLAGE only)

MAX7219 Pin	ESP32 GPIO	Note
VCC	5V	NOT 3.3V!
GND	GND	—
DIN	GPIO 23	Shared MOSI
CS	GPIO 15	Dedicated
CLK	GPIO 18	Shared SCK

Push Buttons → ESP32 (VILLAGE only)

Button	GPIO	Message Sent
Button 1	GPIO 4 + GND	Village is SAFE.
Button 2	GPIO 13 + GND	EMERGENCY! Need help!

Circuit Diagram

📷 Circuit diagram coming soon — place your image at docs/circuit.png and uncomment the line below

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📦 Libraries Required

Install via Arduino IDE → Sketch → Manage Libraries

Library	Author	Install Name
LoRa	Sandeep Mistry	LoRa
MD_Parola	MajicDesigns	MD_Parola
MD_MAX72XX	MajicDesigns	MD_MAX72XX
SPI	Built-in	Pre-installed

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⚙️ LoRa Configuration

Both ESP32s must have identical settings:

LoRa.begin(433E6);
LoRa.setSpreadingFactor(7);
LoRa.setSignalBandwidth(125E3);
LoRa.setCodingRate4(5);
LoRa.setSyncWord(0xF3);
LoRa.enableCrc();