Parts Overview
Edit on GitHubEvery component in the beacon explained in plain language, before you buy anything.
Parts Overview
Before buying anything, understand what each part does. There are nine functional blocks.
The microcontroller: ESP32 DevKit V1
The brain. A dual-core 240 MHz processor with built-in WiFi and Bluetooth. The beacon runs entirely on it: the radio control, the Morse encoder, the OLED, the GPS parsing, and the battery monitor.
The radio: Ebyte E22-400M30S
A complete 433 MHz radio module built around the SX1262 chip, with an onboard power amplifier that can reach +30 dBm. This is what actually transmits the Morse signal.
The display: SSD1309 OLED 2.42”
A 128x64 monochrome OLED on SPI. Shows the mode, frequency, TX progress, battery level, and the scrolling payload. The 2.42” diagonal is much more readable outdoors than the common 0.96” panels.
The GPS: NEO-6M module
A small GPS receiver on UART. When enabled, it appends your coordinates to the Morse payload so rescuers know where you are.
The battery system: 18650 + TP4056
A single 18650 Li-ion cell (3.7 V, ~3000 mAh) powers everything. The TP4056 module charges it over USB-C and provides protection against over-charge and over-discharge.
The audio: 3.5 mm jack + DAC
GPIO 25 is a native DAC. The firmware generates Morse clicks and scan tones that you can hear on any wired headphone.
The controls: 4 tactile buttons
MODE, SEL, UP, DN. They cycle modes, enter config, and adjust volume and Morse speed live.
The indicators: red and blue LEDs
Red blinks in BEACON, blue blinks in SEARCH. Fast blinking patterns signal emergency or a detected signal.
The antenna: quarter-wave wire or whip
About 17.3 cm at 433 MHz. This is what your signal actually travels on; a badly connected antenna can cut range to a few meters.