Embedded Firmware Engineer (PICAD / ESP32 / Zephyr OS)

About the Role:

We are looking for a firmware engineer who really knows how to work with modern hardware (ESP32-S3, PICAD-compatible boards) and Zephyr OS. The main task is to write stable, production-ready code for IoT devices of the "data logger / gateway" level: sensors, Modbus, LTE/Wi-Fi, OTA, local logic, energy saving.

No academic R&D — you need a person who quickly makes a working product.

Responsibilities:

• Development of firmware for Zephyr OS for ESP32-S3 / ESP32-C6;
• Work with PICAD-compatible peripherals (sensors, interfaces, IO);
• Implementation of protocols: Modbus RTU/TCP, UART, RS-485, SPI, I2C;
• Network stack settings: Wi-Fi, LTE (via external modules), MQTT;
• OTA updates (MCUboot, Zephyr samples, custom schematics);
• Data buffering, local storage, fallback modes;
• Integration with backend API (REST/MQTT), queue/telemetry processing;
• Optimization of power consumption and performance;
• Writing unit-/integration-tests, working with hardware-bring-up.

Requirements:

• Deep experience in C/C++ firmware development;
• Commercial experience with Zephyr RTOS is required (device tree, Kconfig, drivers, subsystems);
• Practical experience with ESP32-S3 / ESP32-C3 / ESP32-C6;
• Understanding of MCUboot, partition layout, OTA-pipeline;
• Ability to work with peripherals: UART, SPI, I2C, PWM, ADC, RS-485;
• Experience with Modbus (master/slave), preferably with real devices;
• Debug experience: JTAG, OpenOCD, logic analyzer;
• Git, CI/CD, the ability to work in a normal product, and not "flash firmware".

Nice to have:

• BLE (Zephyr BT stack);
• Python for tooling (scripts, tests, production tools).

We Offer:

• Work on a real IoT product (energy logger / gateway), which is already in production;
• Opportunity for professional growth and career development;
• Vacation — 18 working days per year;
• Friendly working environment;
• Sick leave — 5 working days (without documents);
• Health insurance.