Embedded / RF / Firmware Engineer to $5000

Key Responsibilities

Develop and integrate cryptographic procedures for ELRS: bind phrase encryption, KDF implementation, ECDH/session key replacement, and secure frame handling.

Implement and test FHSS / frequency hopping algorithms — manual and automatic frequency change modes, with adaptation for SX127x / SX128x / LR1122 / LLCC68 and other RF chips.

Adapt and extend Betaflight: add custom MSP/CLI commands, modify flight constraints (arming, angle limits), implement additional AUX modes, and enhance OSD telemetry.

Configure and improve OpenIPC: optimize video streaming (RTSP/OSD), REST/API endpoints, Wi-Fi STA/AP profiles, watchdog systems, and logging mechanisms.

Develop firmware for custom MCU control boards (STM32/ESP32): manage relays/SSRs/indicators, implement safety interlocks and fail-safe logic.

(Safety disclaimer — no instructions or activities related to harmful or explosive devices.)

Conduct comprehensive testing (soak tests, replay/fuzz testing, RF performance analysis), prepare documentation and patches, and manage CI pipelines for firmware builds.

Required Skills & Experience

3+ years of experience in embedded C/C++ development (STM32, ESP32, or similar MCUs).

Hands-on experience with RF modules (LoRa/SX127x) and understanding of FHSS/PRNG principles for hopping.

Solid knowledge of modern cryptography: AEAD (ChaCha20-Poly1305 or AES-GCM), KDF (HKDF, PBKDF2, Argon2), ECDH (Curve25519/X25519).

Experience with Betaflight (forking/patching) or ArduPilot, including code modification and target builds.

Familiarity with Linux / embedded Linux (OpenWRT, Buildroot) and working with gstreamer / ffmpeg for streaming applications.

Proficient with Git and CI/CD for embedded builds.

Understanding of radio regulations (duty cycle, permitted frequency bands) — or readiness to learn and comply.

Basic understanding of hardware schematics: power switches, isolation, relays, and basic SMD soldering for rapid prototyping.

Technical English — Intermediate+ (reading documentation, working with upstream projects).

Preferred Qualifications

Experience developing for OpenIPC or working with camera SoCs.

Background in creating MSP/CRSF/Telemetry integrations for flight controllers.

Practical experience in RF link testing (spectrum, BER/RSSI analysis).

Experience with libsodium, mbedTLS, or OpenSSL on embedded systems.