Staff Embedded Firmware Engineer - Charger

1X; San Carlos (CA); On-site; USD 130,000 - 210,000; Full time

Job summary

1X is developing humanoid home robots and the firmware team writes the embedded software that powers hardware subsystems. This role owns the firmware layer across core hardware to ensure robustness, safety, and maintainability as prototypes scale to production.

You will lead charger firmware development, implement CAN-based interfaces with the BMS, and build control loops for reliable power conversion. Strong background in embedded safety and distributed nodes is essential.

Qualifications

• 5+ years of embedded firmware development in C/C++ on real hardware.
• Experience with interrupts, DMA, timing-critical execution.
• Knowledge of switched-mode power supplies and battery charging.
• Hands-on CAN implementation for charger-to-BMS coordination.
• Firmware safety and fault protection awareness.

Responsibilities

• Develop charger firmware for AC-DC stages and power conversion.
• Implement multi-series Li-ion charge profiling.
• Architect CAN-based charger-to-BMS interface.
• Test, validate, and verify initial firmware releases.
• Develop firmware control loops for voltage and current regulation.
• Implement fault detection and safe-state transitions in firmware.

Skills

Embedded firmware

C/C++

Interrupts

Power electronics

CAN bus

Battery charging

Tools

CAN

SPI

I2C

UART

Job description

About 1X

We're building humanoid robots that work in home - doing the chores, handling the tasks, and giving people their time back. Simple, but it's not.

To do this right, we have to solve robotics, AI, manufacturing - at the same time, at scale, in a form factor that has to be safe enough to live with your family. If you're inspired by this, you'll thrive here. We've been at this since 2014 and we're at the point where the hard problems are behind us and the hard work is in front of us.

NEO is our flagship - a home robot designed to move, learn, and operate in the real world alongside real people. We're not demoing it - we're shipping it. We're excited to meet you, if this excites you.

If you've spent your career working on problems that matter and want to see them actually reach the world - this is that moment. We're scaling, we're hiring with intention, and we need people who want to build something that will genuinely change how humans spend their time - safely creating abundance for all.

About the Team

The Firmware team owns the embedded software layer that powers every hardware subsystem of our humanoid robot from distributed communication bus architecture and power management to actuator and motor drive control. We sit at the intersection of hardware and software, and our work is directly on the critical path to every product milestone: without reliable firmware, the robot cannot move, charge, or operate safely. If you want to build the foundational software for a new category of physical AI, this is where that work happens.

Your Charter

Own the firmware layer across one or more of the robot's core hardware subsystems-ensuring embedded software that is robust, safe, and maintainable across prototype and production platforms. As one of the first companies building general-purpose humanoid robots at scale, firmware quality is non-negotiable: it determines whether the robot operates safely in uncontrolled environments, whether hardware brings up on schedule, and whether the team can move fast as the system grows to 20+ distributed embedded nodes.

Key Outcomes

• Develop and maintain charger firmware controlling AC-DC power conversion stages, including power factor correction and isolated DC-DC conversion topologies
• Implement charge profile management for multi-series lithium-ion packs: constant-current, constant-voltage, and taper phases with cell-chemistry-appropriate voltage and current limits
• Architect the charger-to-BMS communication interface over CAN or similar embedded bus, coordinating charge current requests, pack voltage feedback, temperature limits, and fault signaling between the two subsystems
• Responsible for the testing, validation, and verification of initial firmware releases to ensure functionality, reliability, and performance requirements are met
• Implement power converter control loops in firmware: voltage regulation, current regulation, and soft-start sequencing with stability under varying line and load conditions
• Develop fault detection and protection firmware: input overvoltage/undervoltage, output overcurrent, overtemperature, ground fault, and loss-of-communication with the BMS, each with defined safe-state transitions

Key Competencies

• Deep embedded instincts writing firmware that is correct under real hardware conditions: interrupt timing, DMA conflicts, communication protocol edge cases, and hardware fault behavior
• First-principles problem solver diagnosing novel failures at the firmware-hardware boundary using lab tools and reasoning from fundamentals, not just vendor documentation or established patterns
• Safety-aware by default understanding what 'fail safe' means in a physical system and treats protection logic, fault detection, and safe-state transitions as first-class firmware concerns
• Effective cross-functional partner translating firmware constraints and failure modes clearly to hardware architects, electrical engineers, and systems engineers; supports bring-up without waiting to be directed

Minimum Requirements

• 5+ years of embedded firmware development in C/C++ on real hardware, with direct experience managing interrupts, DMA, and timing-critical execution (7+ years for senior/staff-level positions)
• Power conversion fundamentals working understanding of switched-mode power supply operation: common AC-DC topologies (flyback, LLC, phase-shifted full bridge), power factor correction stages, transformer isolation, and how firmware-controlled parameters (switching frequency, duty cycle, phase shift) affect converter behavior
• Battery charging knowledge: understanding of lithium-ion charge protocols (CC-CV, multi-stage), the relationship between charge rate and cell degradation, and how temperature and cell age affect charge termination criteria
• Embedded bus fluency hands-on CAN implementation for charger-to-BMS coordination, plus additional embedded interfaces (SPI, I²C, UART) for communication with power controller ICs, monitoring devices, and auxiliary ci