Sr. Embedded Firmware Engineer
Summary
Senior Embedded Firmware Engineer at Ironsite owning firmware for ruggedized wearable cameras used on construction jobsites. Builds the full embedded stack in C/C++ on STM32/Nordic MCUs running Zephyr RTOS, including camera/ISP pipelines, sensor drivers, OTA infrastructure, and on-device ML inference for devices scaling into hundreds of thousands of units.
About Ironsite
The Role
What You'll Build
- Develop embedded software for our wearable devices on platforms like STM32 and Nordic, running Zephyr RTOS.
- Write and maintain drivers and libraries for camera, audio, wireless, IMU, and environmental sensors.
- Own end-to-end sensor bring-up on new hardware revisions, from initial silicon through validated production release.
- Optimize for the constraints that matter in a wearable running an 8-12 hour shift: memory, compute, thermal, and battery.
- Own the imaging pipeline end to end, from sensor driver through ISP tuning to encoded video output.
- Tune ISP parameters (demosaicing, color correction, lens shading correction, spatial and temporal noise reduction, HDR/WDR) for the specific lighting and environmental challenges of construction jobsites, including bright outdoor sun, dark building interiors, and everything in between.
- Analyze and balance image quality tradeoffs: sharpness, dynamic range, noise, artifacts, and encoder efficiency, at the resolutions and framerates our data and AI teams depend on.
- Validate image quality across diverse lighting, motion, and environmental conditions, and build the test infrastructure that makes IQ regressions catchable before they ship.
- Run real-time algorithms and lightweight ML inference on-device, including motion detection, event triggering, and preprocessing that reduces upstream compute and bandwidth costs.
- Partner with our AI research team to move selected inference workloads from the cloud to the edge as models mature.
- Build reliable, secure infrastructure for device provisioning, over-the-air firmware updates, and telemetry across a fleet growing from thousands to hundreds of thousands of devices.
- Design the firmware architecture and test infrastructure that makes fleet updates safe, staged, and recoverable.
- Own the debugging tools, logging infrastructure, and observability that let us diagnose issues on devices deployed in the field.
- Collaborate with hardware and manufacturing engineers across the full product lifecycle, from initial architecture and prototype bring-up through DFM, DFT, and volume production.
- Design firmware alongside manufacturing test procedures. Programming stations, functional test, and factory calibration are firmware problems as much as manufacturing problems.
- Support new hardware revisions with rapid firmware iterations, and ensure firmware releases stay tightly aligned with the manufacturing cadence.
What We're Looking For
- 6+ years of hands-on experience shipping embedded firmware on production hardware, with at least one full product lifecycle delivered in wearables, cameras, or IoT devices at real volume.
- Deep expertise in C and C++ for embedded systems with real resource constraints. You've written firmware that lived within tight memory, compute, and power budgets.
- Deep experience with camera and imaging pipelines, including sensor drivers, ISP tuning, and image quality analysis. This is not optional. You've owned an image pipeline in production and can speak concretely about what you tuned, what you fixed, and what tradeoffs you made.
- Strong understanding of ISP core blocks: demosaicing, color correction, lens shading correction, spatial and temporal noise reduction, and HDR/WDR performance.
- Hands-on experience with at least one industry-standard microcontroller platform (STM32, nRF, ESP32, or similar) and one embedded RTOS (Zephyr, FreeRTOS, or similar).
- Comfortable reading schematics and datasheets, and using standard hardware lab tools (oscilloscope, logic analyzer, JTAG, protocol analyzers) to debug hardware-software integration issues.
- Systems thinking across the full embedded stack. From silicon to the cloud, you understand how firmware decisions propagate up and down.
- A background in Electrical Engineering, Computer Engineering, or a related field, or the equivalent experience.
- Experience shipping wearable products at consumer volumes (Fitbit, Oura, Whoop, GoPro, Bose, Apple, Meta, Snap, or similar).
- Experience with wireless connectivity stacks (BLE, Wi-Fi, LTE, or similar) and their power and reliability implications.
- Experience with power management design and low-power firmware techniques.
- Experience shipping OTA update systems for large device fleets.
- Experience with on-device ML inference, including quantization, model deployment on edge accelerators, and inference optimization for constrained platforms.
- Experience with high-speed video encoding pipelines (H.264, H.265, AV1) and the codec-side tradeoffs.
- Experience with audio processing pipelines (even though we don't capture audio on our devices, adjacent experience often transfers).
- Experience contributing to Zephyr OS upstream or maintaining fork-level customizations.
What Success Looks Like
- First 90 days. You know our hardware platform cold, including the sensor stack, the ISP, the RTOS configuration, and the manufacturing test infrastructure. You've shipped your first meaningful firmware improvement to production devices.
- First 6 months. You've owned a major firmware initiative end to end, whether it's a next-generation camera bring-up, a fleet-wide OTA architecture improvement, or a battery life optimization that materially extends shift capacity. Your work is running on every deployed device.
- First 12 months. You're the internal authority on firmware at Ironsite. Our devices are more reliable, more efficient, and easier to update because of you. When we scale from thousands of devices to hundreds of thousands, we do it because the firmware you built holds up.
Location, Compensation, & Perks
- San Francisco Bay Area (on-site)
- Base salary: $200k-$300k per year, commensurate with experience
- Significant early-stage equity
- Full benefits including health, dental, vision, and 401(k) with 6% match
- Daily catered breakfast and lunch
- Office in San Francisco, next to Oracle Park and the Caltrain