PCB / Embedded Systems Engineer - Custom Integrated Vehicle Controller

Overview: We're a US-based robotics company replacing a COTS Pixhawk + Raspberry Pi + discrete ESC/power stack with a single custom integrated vehicle-controller PCB for a production marine robotics platform. The vehicle and application details are confidential (shared under NDA after engagement), but the electronics problem is fully specified and self-contained: you will receive a complete hardware design specification with numbered requirements, interface definitions, and acceptance criteria on day one. This is a well-scoped design-to-bring-up engagement, not an open-ended R&D project. The stack you're replacing has been water-validated on working prototypes. Your board is the production version. What You're Building: One main carrier board plus one small companion ESC board: Main board (four domains): - Real-time flight-controller domain — STM32H743/H757, dual SPI IMUs (ICM-42688-P class), RM3100 magnetometer, internal barometer, FRAM + SD/eMMC logging, multiple UARTs (GNSS w/ PPS, acoustic modem, telemetry, companion link), 2× CAN-FD, discrete safety I/O, optional 10/100 Ethernet PHY - Compute domain — NVIDIA Jetson Orin Nano/NX SO-DIMM carrier per the NVIDIA Design Guide (power sequencing, strapping, conduction cooling — no airflow), M.2 2280 NVMe slot, USB/camera/radio breakouts - Power domain — 4S–6S Li battery input, buck-boost charge controller fed from an inductive docking/charging receiver, ideal-diode ORing power path, coulomb-counting fuel gauge, per-subsystem software-switched and current-monitored-rails - Supervisor domain — independent low-power MCU (STM32G0/L0 class) with watchdog authority over the main MCU and Jetson, battery disconnect, RTC wake scheduling, and charge-while-asleep management; whole-system sleep current target greater than 1 mA Companion ESC board: 8× ESC stages (≥30 A continuous each at 6S) running AM32 firmware, bidirectional DShot600 with RPM telemetry, per-channel current sense. Connected to the main board by DC bus + CAN + DShot only. Critical firmware constraint (drives your part selection): the board runs a fork of ArduPilot and must be implemented as a custom ArduPilot board target — you deliver the hwdef.dat, an ArduPilot-compatible bootloader, and a bring-up build with all peripherals enumerated. Every sensor, PHY, and peripheral must have an existing mainline ArduPilot driver. If you've brought up a custom ArduPilot/PX4 board before, this project will feel very familiar. Deliverables: - Schematic and layout source (KiCad 8+ strongly preferred; Altium acceptable with source files) 3D STEP, Gerbers, drill, pick-and-place, BOM with alternates and sourcing notes = hwdef.dat, bootloader, and bring-up firmware build (all peripherals healthy, EKF running on bench) = Supervisor MCU firmware (watchdog, power sequencing, wake/sleep, charge supervision) = Power tree, connector pinout book, main-board ↔ ESC-board interface control document, connector pin-current budget analysis = 5 assembled prototype sets with recorded bring-up/acceptance results Milestones (fixed-price per milestone) M0 — Kickoff & architecture review: confirm envelope, battery pack, thruster loads, Jetson variant, camera interface; freeze part selections against the ArduPilot driver list M1 — Schematic review: full schematics, power tree, pinout book, pin-current budget, BOM cost check M2 — Layout review: placement (magnetometer/IMU keep-outs, Jetson thermal path), stack-up, DFM check M3 — Fab & assembly: 5 prototype sets built and inspected M4 — Bring-up complete: all acceptance criteria demonstrated and recorded (sensors healthy, bidirectional DShot on 8 channels, charge path, sleep current, watchdog recovery) M5 — Integration support & handoff: support first system integration; final documentation and DFM notes for the production spin Required Skills & Experience - 5+ years of professional mixed-signal PCB design with shipped hardware (please link boards you've taken to production) - STM32 family design and bring-up, ideally STM32H7 - Direct experience creating a custom ArduPilot or PX4 board target (hwdef/board config, bootloader, driver bring-up) — this is the single strongest qualifier for this job - Power electronics: Li-ion charge management, ideal-diode/ORing power paths, load switching, low-quiescent-current sleep design - NVIDIA Jetson SO-DIMM carrier design per the official Design Guide (or closely comparable SoM carrier work) - Brushless motor drive / ESC design or deep integration experience (DShot, AM32/BLHeli ecosystems, per-channel current sensing) - EMI/EMC-aware layout, especially magnetometer and IMU placement near switching regulators and high-current buses - DFM for standard 4–6 layer fab and turnkey assembly; managing a prototype build with JLC/PCBWay-class vendors Nice to Have - Marine, subsea, or other sealed-enclosure electronics experience (conformal coating, humidity, operation at reduced cabin pressure) - CAN-FD / DroneCAN peripheral design - Ethernet PHY integration on STM32 - Experience writing small bare-metal supervisor/companion MCU firmware