Principal Firmware Engineer

About SiPhox Health

SiPhox Health is redefining diagnostics by bringing silicon-photonics-based clinical instruments out of the central lab and into the home. Our platform unites photonics, microfluidics, embedded systems, and semiconductor-grade manufacturing to deliver precise, multiplexed biomarker quantification in minutes on a device the size of a coffee maker.

We are building what we believe will become the first mass-market photonic blood analyzer, an at-home diagnostic platform that enables continuous, data-driven improvement in chronic disease management.

Firmware sits at the core of this transformation. It orchestrates the entire system: optics, fluidics, thermal control, sensing, motion, safety, and user experience. We are now hiring the engineer who will architect and own this layer.

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.

What You’ll Do

Core Firmware Architecture & Development

• 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.

Cross-Functional System Integration

• 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.

Reliability, Safety & Risk Management

• 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.

Debugging & Performance Optimization

• 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.

What We’re Looking For

Technical Background

• Extensive experience developing embedded firmware for medical devices, diagnostics, or drug-delivery systems under ISO 13485 and IEC 62304 (Class C preferred).
• 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 STM32, ESP32, NXP, Nordic, or similar.
• Deep familiarity with RTOS environments (FreeRTOS, Zephyr, ThreadX, 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 (<10%).

Highly Desirable

• Successfully bringing an IVD instrument or medical device from R&D to commercial launch.
• Experience with precision liquid-handling or fluidic automation systems.
• Familiarity with cybersecurity and data-integrity standards (21 CFR Part 11, HIPAA, IEC 80001).
• Experience with sensor calibration, data-acquisition systems, wireless connectivity, or automated manufacturing fixtures.

Why This Role Is Unique

Most embedded engineers will spend their careers working on incremental improvements to platforms that already exist.

At SiPhox, you will:

• Build the first firmware stack driving a silicon-photonic diagnostic device deployed in consumer health.
• Architect real-time control systems that combine optics, fluidics, motion, and sensing, all in a compact at-home form factor.
• Work on challenges where embedded engineering, medical-device safety, photonic physics, and microfluidics intersect.
• See your firmware power the instrument that brings lab-quality diagnostics directly into people’s homes.

If you want to engineer the firmware layer of a new category of diagnostic platforms, and build something that will fundamentally shift preventive and chronic-disease care, we’d love to meet you.