Documentation
Onboarding
Budget Planning Common Beginner Mistakes First Boot Learning Path Legal Basics for Beginners How the Beacon Saves Lives Understanding the Modes in One Page Morse Code for Beginners Parts Overview Reading the OLED Screens Radio Basics for Complete Beginners Safety First Tools You Need Using the BOM Builder Using the Interactive Demo Welcome to the Wiki
Getting Started
Bench Power Bench Testing Basics Boot Process Build Configurations Choosing a Build Configuration Static Safety and ESD ESP32 Troubleshooting Checklist Frequently Asked Questions First Transmission First Use Project Overview Quick Start Guide Shopping List Sourcing Parts System Architecture Troubleshooting Version Selection Workspace Setup
Power & Battery
18650 Battery Guide 18650 Safety Notes Alternate Power Inputs Battery Capacity Math Battery Field Swap Battery Monitor Calibration Battery Monitor Details Battery Selection and Management Battery Storage Battery Troubleshooting Brownout Protection Buck-Boost Converters Cell Chemistry Cell Discharge Curve Charger Troubleshooting Charging and Cell Care Cold Weather Batteries Current Draw by Mode E22 Power Levels ESP32 Power Input First Power-On Protocol GPS Power Saving Parallel Cells Power Budget and Runtimes Power Management Power Measurement Power Quick Reference Protected vs Unprotected Cells Sleep Current Solar Build Solar Charging TP4056 Charger Guide TP4056 Charging Current TP4056 Wiring Undervoltage Protection
Hardware & Components
Audio Alert System Audio Tone Details ESP32 Board Variants Button Types Guide Buzzer Types E22 Module Pinout E22 Radio Module Guide E22 vs Bare SX1262 ESP32 Board Guide ESP32 Board Variants ESP32 Deep Sleep Hardware ESP32 Flash and Partitions ESP32 Input-Only Pins ESP32 Sleep Modes ESP32 USB Chips Firmware OLED Rendering GPS Antenna Types GPS Module Buying Guide GPS Module Variants Hardware Components LED Status Indicators LED Indicators Wiring NEO-6M GPS Module Guide NEO-6M GPS Module NEO-6M vs NEO-M8N OLED Display OLED Library Notes OLED Panel Guide OLED Panel Life OLED Panel Specs OLED SPI vs I2C Display Selection Guide Display GPIO and Pin Reference ST7735 TFT Display HD44780 LCD Displays Radio Library and SX1262 Radio Module Variants
Build & Assembly
3D Printing the Enclosure Assembly Guide Assembly Sequence Audio Jack Wiring Audio Troubleshooting Bench Checklist Breadboard Prototyping Building Your Own Case Button Actions in CONFIG Mode Button System Details Button Troubleshooting Case Cutouts Guide Case Materials Circuit Description Connector Types Datasheet Reading Dummy Load and Bench Testing Electrical Specifications Enclosure Options Flux and Solder Glue and Adhesives GPIO Pin Map Reference GPIO Pin Mapping Ground Planes and Counterpoises Ohm's Law Resistors, Capacitors and Passives Schematic Reading Screw and Fastener Guide Soldering Basics Soldering Iron Guide Two-Beacon Bench Test Waterproof Build Waterproofing and Enclosure Sealing Wire and Connectors Wire Gauge Guide Wiring and Connectors Wiring Order and Routing Wiring Quick Reference
Radio & RF Design
Antenna Cable and Connectors Antenna Design Antenna Efficiency Antenna Height Matters Antenna Length Reference Antenna Mounting Antenna Quick Select Antenna Testing and Tuning Antenna Theory Primer Antenna Troubleshooting Antenna Design and Selection Coax Loss Tables dBm Explained Foliage Loss The Fresnel Zone GPS Antenna Placement Half Wave Dipole Helical Antenna Homebrew Antenna Interference Sources at 433 MHz Line of Sight and Terrain LoRa vs FSK Modulation in the Beacon Morse Timing and Audio Sync Mountain Effects on Radio Propagation and Range Propagation Modes Quarter Wave Antenna Radio Quick Start Radio Shadow Receiver Testing RF Basics for the Beacon RF Design & Link Budget RF Exposure Safety RF Interference and Noise RSSI Explained Sensitivity vs Selectivity SWR Explained SX1262 Datasheet Notes SX1262 Frequency Ranges SX1262 Registers Transmitter Testing Tropospheric Ducting Troubleshooting RF Issues Urban RF Environment VSWR Measurement
Frequencies & Regulations
The 70 cm Amateur Band Amateur License Process Austria Radio Legal Callsign Identification Duty Cycle Rules Emergency Frequencies Emergency Use Legal ERP vs EIRP France Radio Legal Frequency Compatibility Frequency Planning Examples Frequency Table Reference Germany Radio Legal ISM Bands Explained Italy Radio Legal License Classes PMR446 Deep Dive Regulatory Compliance Safety and Liability Scanning the Band Switzerland Radio Legal UK Radio Legal US Radio Legal
Firmware & Software
Arduino CLI Guide Boot Loop Troubleshooting Boot Screens and Errors Changelog Code Style Guide Config Backup Config Dashboard Why the Dashboard Uses System Fonts CONFIG Payload Format Configuration Reference Dashboard HTTP API Dashboard Rendering ESP32 ADC Guide ESP32 Flash Security ESP32 Interrupts Guide ESP32 RTC Notes ESP32 Serial Debug Output ESP32 Timers Guide ESP32 WiFi Hardware esptool Guide Extending the Serial Protocol Factory Reset and Recovery Firmware CW Decoder Firmware System Monitoring Frequency Setting over Serial The Button System in Firmware How Firmware Loads Configuration Firmware Deep Sleep Firmware Error Codes Firmware GPS Handling The Firmware Main Loop Firmware NVS Keys Firmware Overview The Payload Builder Firmware RSSI Measurement The Scan Cycle in Detail Firmware Scan Engine The Firmware State Machine Firmware Tone Generation The TX Cycle in Detail Firmware TX Scheduler Upgrading to v5.5 Firmware Update in the Field Firmware Wake Sources The Watchdog Benchmark Demo Mode Flash Troubleshooting No Boot? Troubleshooting No Display? Troubleshooting NVS Configuration Store PlatformIO Guide RTC RAM State Battery Logging over Serial Serial Bridge Guide Serial Command Automation Serial Command Protocol Serial Debug System Serial Monitor Guide Software Build Process Unit Testing the Firmware Upload and Monitor What's New in v5.5 What's New in v6.0 WiFi and Security WiFi Configuration Portal WiFi Troubleshooting
USB & Connectivity
Android OTG Guide Bridge Automation Bridge Security Bridge Troubleshooting Bridge TUI CH340 Driver Install CP210x Driver Install Report Position Page USB-Serial Adapter Troubleshooting Serial Port Detection Termux: Serial Bridge on Android USB Cable Types USB Connection Guide USB Power vs Data Web Serial: Browser-Only Option
GPS & Navigation
Coordinate Conversion Coordinate Plotting and Maps GPS Build Configuration GPS Coordinate Accuracy GPS Coordinate Systems GPS Failure Contingency GPS Fix Capture Tips GPS Fix Quality GPS Integration GPS NMEA Sentences GPS Quick Fix GPS Satellite Count GPS Sky View GPS Testing Indoors GPS Timing GPS Troubleshooting GPS UTM vs Decimal GPS Warm vs Cold Start Position Reporting Configuring the NEO-6M over UART
Morse & Communication
Audio Recording Guide Band Plan Etiquette Decibel Table Mayday vs Pan Pan Morse Abbreviations and Prosigns Morse Audio Cheat Sheet Morse Code Engine Morse Code Learning Apps Morse Decoder Tools Morse Code Background Morse Keying Practice Morse Listening Workflow Morse Letter Table Morse Numbers and Punctuation Morse Practice Morse Timing Reference Payload Examples Phonetics Q Codes Radio Communication Basics Radio Etiquette Basics Reading CW by Ear Receiver Compatibility Rescue Communication Basics SDR Beacon Build SDR Decoding Morse SDR Listening Guide SDR Software Setup Signal Reporting Conventions Simplex Communication Spectrum Analyzers Two-Way Build
Modes & Operation
Glossary of Modes and Settings BEACON Mode CONFIG Mode EMERGENCY Mode LISTEN Mode SEARCH Mode Mode Screens and Icons Operating Modes Scan Engine Details
Field Operations & Rescue
Avalanche Rescue Operation Avalanche Safety Basics Beacon Care Seasonal Beacon Log Template Cleaning and Inspection Crevasse Rescue Distance Estimation from RSSI Emergency Cheat Sheet Emergency Communications Plan Emergency Kit Emergency Response Minute by Minute Emergency Response Scenarios Field Checklist Field Deployment Guide Field Maintenance and Storage Field Repair Kit Field Signals Cheat Sheet First Aid Kit Ground to Air Signals Group Communication Plan Hiking Safety Homing Technique Homing with the Serial Bridge Hypothermia Recognition Incident Command Long Term Storage Mirror Signaling Mission Debrief One Bridge, Several Beacons Night Operations Off-Grid Position Sharing Outdoor Testing Guide Pack Check Routine Position Logging Workflow Pre-Trip Checklist Repeater Position Reporting Ridge Crossing Technique Safety Guidelines Safety Quick Rules Search Patterns and Procedure Signal Strength Mapping Signal Triangulation Signaling Techniques Snow and Signal Behavior Snow Shelter Signaling Snow Signal Math Storm Operations Terrain Reading for Radio Trip Planning Water Damage Recovery Weather Planning Whistle Signals Winter Operations Winter Pack
Building Effectively
Effective Build Strategy Build Quality Gates Bench Jigs and Fixtures Rework and Desoldering Build Time Planning Build Log and Tracking
Build Variants
Displayless Build Minimal Build Multi-Beacon Network Multi-Beacon Operations Multi-Beacon Frequency Planning Repeater Beacon Standard Build Configuration
Project & Reference
Acknowledgements Attribution and License Benchmark Methodology Beacon Settings Reference Branding CI/CD Commercial PLB vs DIY Community Resources Comparison with Alternatives Configuration Quick Guide Contact and Support Contributing to Aegis-Beacon Deployment Feature Requests Git Basics GitHub Workflow Guide Glossary Project History Quick Reference Sheet Release Process Reliability & Safety Features Reporting Issues Roadmap Robots and Sitemap SEO Test Procedures Overview Translations Unit Conversions Why 433 MHz
Docs Project & Reference Project History

Project History

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How Aegis-Beacon came to be: the design journey from prototype to the current firmware, and the decisions that shaped it.

Project History

Every design decision in the beacon has a history. This page is the story of how a personal project became a documented, testable rescue device.

The beginning

Aegis-Beacon was created by Leonardo Galli (GitHub: Leo-Galli/Aegis-Beacon) as a personal project and is released under the MIT License.

The project started with a simple observation: commercial personal locator beacons cost hundreds of euros and rely on proprietary satellite networks. The question was whether a capable rescue beacon could be built from off-the-shelf hobby parts for under thirty euros, on the license-free 433 MHz band, using nothing more exotic than Morse code.

The first prototype

The earliest builds were breadboard experiments: an ESP32, a LoRa module, a button and a wire antenna. They transmitted, which proved the concept, and immediately exposed the real problems: battery life measured in hours, no way to configure in the field, and a payload format that only the developer understood.

The decisions that stuck

DecisionWhy
433 MHz ISM bandUniversal receivers, license-free within limits (see Why 433 MHz)
Morse code payloadAny receiver and human ear can decode it, no proprietary protocol
OLED + buttonsField configuration without a computer
Deep sleep architectureThe difference between hours and days of runtime
GPS as optionalCoordinates matter, but the beacon must work without them

The version line

The firmware went through the versions documented in the Changelog: the config format was reworked (v4 to v5), the dashboard became part of the firmware itself, and the scan engine was added. Each version fixed a real field problem.

The website and wiki

Documentation came last, deliberately: the project’s lessons are worthless if they stay in one developer’s head. The website, the demo, the builder and this wiki exist to make the beacon reproducible by anyone.