Aegis-Beacon is an open-source, ultra-low-cost emergency rescue beacon designed for avalanche survival, backcountry emergencies, and SAR operations.

What is Aegis-Beacon?

Aegis-Beacon is a professional emergency radio-location system based on LoRa technology. It fits in a jacket pocket, costs around $23-28 to build, and can operate for 70+ hours on a single 18650 cell in BEACON mode.

Key Statistics

Metric	Value
Total BOM Cost	`~$23-28 USD`
Frequency Range	`410-525 MHz`
Max Range (LOS)	`15 km`
Deep Sleep Current	`10 uA`
Operating Modes	`4`
Display	`SSD1309 2.42" OLED`

Core Features

Radio & Transmission

SX1262 CW keying — manual FSK carrier on/off
Up to +22 dBm via RadioLib; +30 dBm with E22-400M30S PA
Frequency hopping — up to 10 configurable frequencies per cycle
PARIS-standard Morse timing — dot / dash / gaps calibrated to WPM

GPS & Battery

NEO-6M GPS module on UART2 (GPIO 22 RX, TX unconnected)
Coordinates in Morse — compact DDM format: N4553 E01230
Battery monitor — live percentage and voltage via voltage divider
Charging detection — CHG shown when TP4056 STDBY pin detects charge

Physical Controls

4-button panel — MODE, SEL, UP, DN for instant mode switching
Live adjustment — VOL/WPM adjustable without opening config portal
Auto-repeat — hold UP/DN for fast repeat after 500 ms
Factory reset — hold MODE + SEL at boot for 5 s

Operating Modes

Mode	Description	Power
BEACON	Transmits Morse SOS + GPS on all configured frequencies	`+17 dBm`
SEARCH	Scans all frequencies, measures RSSI, audio alert on detection	`Rx only`
CONFIG	WiFi AP mode with captive portal dashboard	`WiFi AP`
EMERGENCY	Maximum power continuous TX with full payload, no deep sleep	`+22 dBm`

Warning

EMERGENCY mode consumes maximum power. Use only in critical situations where immediate rescue communication is required.

Hardware Platform (v5.5)

Component	Part	Role
MCU	ESP32 DevKit V1 (30-pin)	Control, WiFi, deep sleep
Radio	Ebyte E22-400M30S (SX1262)	CW/FSK TX + RSSI scan, up to +30 dBm PA
Display	SSD1309 2.42” OLED (SPI)	Mode UI, battery, GPS state
GPS	NEO-6M (UART2)	Coordinates in the Morse payload
Battery	18650 Li-ion + TP4056	Power and USB-C charging
Audio	GPIO 25 DAC1 + 3.5 mm jack	Morse clicks and RSSI audio alerts
Controls	4 tactile buttons	MODE / SEL / UP / DN

What Changed in v5.x

Aegis-Beacon v5.5 builds on the v5.4 hardware revision of the original v4.0 design:

ESP32-C3 -> ESP32 DevKit V1 with native DAC1 audio (cleaner tone)
SX1276 -> SX1262 (E22 module): CW keying, +30 dBm PA, and a mandatory BUSY pin
0.96” I2C -> 2.42” SPI OLED driven by U8g2 (flicker-free full-frame buffer)
Added GPS with compact DDM coordinates (N4553 E01230) sent in Morse
Added a battery monitor (ADC divider -> % + mV, live on every screen)
Added 4 physical buttons for live VOL/WPM adjustment without the dashboard

Important

GPIO assignments changed completely between v4.0 and v5.x. Do not run v5.x firmware on the old ESP32-C3 + RA-02 hardware without rewiring. See the GPIO Pin Map.

Project Layout

Path	What lives there
`AegisBeacon.ino`	Full ESP32 firmware (single file)
`README.md`	Short project overview and quick start
`DATASHEET.md`	Single merged reference: electrical specs, GPIO map, technology stack and the global SAR frequency database
`CONTRIBUTING.md`	Contribution guide and automated PR workflow documentation
`website/`	This documentation site, demo and BOM builder

Quick Links

Quick Start Guide — Get started in 5 minutes
Hardware Components — Full BOM and wiring
Assembly Guide — Step-by-step build instructions
Firmware Overview — Code structure and dependencies
Operating Modes — BEACON, SEARCH, CONFIG, EMERGENCY
BOM Builder — Interactive cost calculator