Long-range radio link
SX1262 transceiver with a +30 dBm power amplifier reaches up to 15 km line-of-sight across the 410-525 MHz band. The firmware sweeps a preloaded frequency list, so a rescuer with a cheap SDR will hear the beacon.
Field rescue radio - 433 MHz - v6.0
A rescue beacon that broadcasts your position when every network is gone.
Radio-location for mountain rescue and SAR teams, built from off-the-shelf parts. No GSM, no subscriptions, no network to transmit.
- Bill of materials$23-28
- Band410-525 MHz
- Runtime65h+
- Range15 km
- Deep sleep10 uA
Radio, GPS and display in a pocket-sized case. One button starts the beacon.
On air
Built to be heard, not to be found on a network
When every other link drops, a direct radio signal still carries. The beacon encodes your name and position into Morse and sweeps a preloaded list of rescue frequencies, so any receiver tuned to the band can hear you.
- One press in BEACON mode starts the full SOS cycle.
- EMERGENCY raises power to +22 dBm and transmits continuously.
- No SIM, no account, no network: only the radio in your hand.
Designed around one job: being found
Every component and every line of firmware exists to get your position to a rescuer, with nothing left to fail.
Ultra-low power
Deep sleep at 10 uA with a 30-second hardware watchdog. WiFi and Bluetooth are disabled in beacon mode, pushing runtime past 65 hours on a single 18650 cell.
No infrastructure
Direct peer-to-peer radio. No GSM, WiFi, or satellite link is required, so the beacon works in canyons, forests, and anywhere cellular coverage ends.
Open source, MIT
Firmware, schematics, and the full bill of materials are MIT licensed and built with PlatformIO. Anyone can inspect, modify, and verify the rescue logic.
GPS-aware beaconing
The NEO-6M GPS module encodes coordinates directly into the Morse payload, so search teams receive a position without any proprietary protocol.
Four operating modes
A single button cycles the device between beacon, search, configuration, and emergency transmission.
BEACON
Transmits Morse SOS with GPS coordinates on all configured frequencies, then enters a deep-sleep cycle for maximum runtime.
SEARCH
Scans every frequency sequentially and measures RSSI on each, with a rising-pitch audio alert when a signal is detected.
CONFIG
WiFi access point with a captive-portal dashboard. Adjust frequency, WPM, power, and GPS settings from a browser, no reflash.
EMERGENCY
Maximum power, continuous transmission, full payload. No deep sleep. A 1760 Hz audible tone for critical rescue situations.
Industry-standard components
ESP32SX1262SSD1309NEO-6MRadioLibPlatformIO
Six parts. Every one chosen for availability and long production lifetime.
Frequently asked questions
What is the total cost to build an Aegis-Beacon?
The complete bill of materials costs between $23 and $28 depending on sourcing. All components are readily available from AliExpress or local electronics stores. No specialized tools beyond a soldering iron are needed.
Does it require any cellular or internet connection?
No. Aegis-Beacon uses direct peer-to-peer LoRa radio communication. It works entirely offline. No GSM, WiFi, or satellite subscription is needed for emergency beacon operation. WiFi is only used in Config mode for local settings adjustment.
What is the maximum range?
Up to 15 km line-of-sight with the included antenna at +17 dBm TX power. In Emergency mode, continuous transmission at +22 dBm extends range further. Real-world range depends on terrain, obstacles, and antenna orientation.
How long does the battery last?
In Beacon mode with a standard 18650 cell (3000 mAh), expect 65+ hours of continuous operation. The device enters deep sleep at 10 uA between transmissions, maximizing battery life for extended rescue operations.
Is this legal to use?
The device operates in the 410-525 MHz band. Check your local regulations for unlicensed radio operation. In many jurisdictions, low-power emergency beacons are permitted. The firmware supports PMR446-compliant frequencies.
How do I configure the device?
Switch to Config mode to activate the WiFi Access Point. Connect to "AEGIS-SETUP" and open 192.168.4.1 in your browser. The captive portal lets you adjust every parameter without reflashing the firmware.
Aegis-Beacon v6.0
Built in the open, for the field
Follow the build guide, plan your bill of materials, and assemble your own rescue beacon.