Hardware / PCB Design Engineer for Smart Smoke + CO & IAQ Detector Prototype (ESP32)

We are seeking an experienced Hardware and PCB Design Engineer to develop the internal electronics prototype for HalоSense, a next-generation smart smoke, carbon monoxide, and indoor air quality monitor. This stage focuses strictly on the internal electronics architecture, schematic design, PCB layout, component selection, and prototype bring-up testing. Enclosure design is handled separately. The core architecture relies on an ESP32 series MCU for Wi-Fi and Bluetooth LE. Life safety features include a photoelectric smoke detection circuit and an electrochemical CO sensor. For indoor air quality, we plan to use an all-in-one low-profile module (such as the Cubic AM1008 or AM1002) for optical laser particle counting (PM1.0, PM2.5, PM10), VOCs, temperature, and humidity. The design also includes a PIR motion sensor for a low-power red night-light LED, a piezo alarm buzzer, status LEDs, a test/silence button, and low-battery monitoring. The power stage must support mains power with a rechargeable Li-ion backup battery, including duty-cycling for high-draw sensors. Crucially, core smoke and CO detection must operate 100% locally and independently from Wi-Fi, app connectivity, or IAQ states. Key deliverables include complete schematics, an optimized PCB layout fitting a target envelope of ~120 x 120 x 40mm, a detailed BOM with commercial parts, standard manufacturing files (Gerbers, Pick & Place, NC Drill), and support with component sourcing, assembly review, and initial hardware testing. The ideal candidate has strong experience in electrical engineering, embedded systems, and PCB design with ESP32 microcontrollers, low-power IoT devices, and multi-sensor layout optimization. We value clear, proactive communication and a collaborative approach.