Principal Firmware Engineer

+++ The Opportunity +++

We are looking for a Principal Firmware Engineer who wants to build the firmware foundation for a new category of diagnostic instrumentation. If you thrive at the intersection of real-time embedded systems, electro-mechanical control, and safety-critical medical-device firmware, and want your work to directly power a consumer device used in millions of homes, this is one of the most unique engineering roles available today.

This position owns the firmware architecture across our diagnostic platform, working closely with electrical engineering, systems engineering, assay chemistry, photonics, fluidics, and mechanical engineering. You will design the real-time behaviors that make a complex, multi-domain instrument operate with precision, safety, and medical-grade reliability.

• Design, implement, and maintain production-grade embedded firmware for SiPhox’s photonic diagnostic platform.
• Architect system modules, hardware-abstraction layers, real-time state machines, event-driven behaviors, and inter-module communication.
• Translate functional and system-level needs into clear, verifiable software requirements and design specifications.
• Develop firmware documentation aligned with IEC 62304 (Class
  
  C) and SiPhox’s ISO 13485 QMS.
• Create robust bootloaders, test fixture firmware, calibration flows, and system diagnostics.

• Integrate firmware with electronics, sensors, photonic subsystems, motion systems, microfluidics, and cloud/companion software.
• Collaborate deeply with electrical, mechanical, assay, and software teams to ensure cohesive system behavior across all modules.
• Drive system bring‑up and iterative refinement, from early prototypes through verification, validation, and commercial release.

• Lead firmware contributions to hazard analysis, risk‑control implementation, FMEAs, and safety mitigations.
• Architect deterministic, fault‑tolerant state machines for safety‑critical operations.
• Establish verification strategies, test harnesses, automated testing, and traceability for all firmware features.

• Diagnose complex, multi‑disciplinary issues across firmware, electronics, sensors, and electro‑mechanical subsystems.
• Optimize real‑time control loops, timing behavior, memory constraints, and processor utilization.
• Ensure long‑term maintainability, modularity, and scalability of the firmware stack.

• Strong grounding in risk management aligned to ISO 14971.
• Expertise in C/C++, including low‑level drivers, HALs, real‑time control, and MCU bring‑up.
• Experience with major MCU families such as STM
  32, ESP
  32, NXP, Nordic
  , or similar.
• Deep familiarity with RTOS environments (FreeRTOS, Zephyr, Thread
  
  X, VxWorks, etc.).
• Background in electro‑mechanical motion control (e.g., X‑Y‑Z gantry systems, stepper/servo control, closed‑loop control).
• Proven ability to architect complex, modular firmware systems with reliability and safety at the forefront.
• Exceptional debugging skills across hardware, firmware, and mechanical/electromechanical interfaces.
• Strong communicator and highly cross‑functional collaborator.
• Bachelor’s degree in EE, CE, CS, or a related field (or equivalent experience).
• Authorized to work in the U.S.; able to travel occasionally (