Curriculum vitae

Carl Henriksson

Firmware Engineer · Systems Engineer · Product Developer

cv@carlhenriksson.comgithub.com/carlhenrikssonlinkedin.com/in/carlhenrikssonOslo, Norway

Profile

Systems engineer and product developer with decades of hands-on experience spanning firmware, infrastructure, and production software. I build and operate real-world systems with a focus on automation, reproducibility, operational simplicity, and long-term maintainability. Alongside engineering, I bring extensive customer-facing and commercial experience, including training, stakeholder communication, and high-trust operational responsibility.

Core Strengths

  • Firmware & embedded: Zephyr/ZMK, nRF52840, HID, device drivers, hardware bring-up, sensor integration.
  • Systems & infrastructure: OpenBSD, segmented networks, default-deny architecture, deployment automation, CI/CD.
  • Production software: real-user applications, backend systems, realtime sync, offline-first design, operational ownership.
  • Delivery & leadership: customer-facing responsibility, stakeholder communication, staff training, trust-based execution.
  • Engineering practice: reproducible builds, validation, testing, deployment pipelines, and documentation.

Skills

Firmware / Embedded

ZMK, Zephyr, nRF52840, Bluetooth HID, USB HID, device trees, Kconfig, SPI, GPIO, sensor drivers, hardware bring-up

Systems / Backend

Python, Linux, REST APIs, SQLite, validation, deterministic builds, service workers, Cloudflare Pages, Durable Objects

Web / Product

JavaScript, WebSockets, Web Audio, offline-first UX, static sites, accessibility, product copy, launch-ready documentation

Commercial Strengths

Sales, negotiation, client communication, stakeholder management, discovery, product framing, trust-building

Operational Engineering

Version control, CI/CD, automated tests, generated artifacts, reproducible builds, deployment pipelines, validation gates, low-maintenance systems

Technical Highlights

  • Contributed a Realtek network driver fix upstream to OpenBSD after debugging unsupported hardware during a router deployment.
  • Designed and operate a segmented infrastructure with explicit trust boundaries and default-deny network policy.
  • Developed production ZMK/Zephyr firmware for nRF52840 devices, including a custom MA730 magnetic encoder driver.
  • Built and operate production web applications with realtime synchronization, offline support, and deployment automation.
  • Developed backend systems for audio analysis, metadata processing, search, validation, and playlist generation.

Selected Projects

OpenBSD Contribution

Upstream network driver contribution. Identified unsupported Realtek NIC hardware while deploying a segmented OpenBSD router, implemented support for the hardware revision, stress-tested the fix, and contributed it upstream where it was merged into OpenBSD.

Infrastructure Architecture

Router-centric segmented network design. Designed an explicit-trust infrastructure model with isolated control planes, default-deny routing, defined flow policies, management separation, and operational invariants across multiple trust domains.

MOTR

Production firmware currently used in daily operation by multiple users. Developed an out-of-tree Zephyr/ZMK board port with device-tree integration, keymap configuration, custom MA730 magnetic encoder input driver, USB/Bluetooth HID support, battery reporting, RGB underglow, and CI-generated UF2 builds.

WeekFirst

Production habit-tracking application with active users. Built a static web app backed by Cloudflare Pages Functions and Durable Objects, with WebSocket sync, REST fallback, localStorage cache, offline behavior, user-code identity, and multi-device state replication.

AutoDJ

Music-library analysis and export platform. Built a Python backend for audio metadata, analysis sessions, validation, search/filtering, pagination, saved filters, API contracts, and playlist export workflows.

SBFW

Deterministic static website administrator. Built a Python pipeline for metadata, manifests, service workers, sitemap, robots, security.txt, asset validation, monolith output, and deployable static artifacts.

Folio

Markdown-to-SBFW layout engine. Built content discovery, frontmatter parsing, wikilinks, transclusion, element injection, design token generation, and a clean boundary into SBFW.

RumbleVoice

Browser-based voice and breathing trainer. Built a focused Web Audio and animation experience with timing controls, accessibility states, reduced-motion behavior, and product-led explanatory copy.

Experience

Independent Systems Engineering / Firmware / Product Work

Production apps, firmware, infrastructure, and open-source contribution

C · Zephyr/ZMK · OpenBSD · Python · JavaScript · Cloudflare · Linux · GitHub Actions

  • Designed and delivered software, firmware, and infrastructure projects across embedded, backend, and web domains.
  • Maintained deployment pipelines, documentation, testing, validation, and operational ownership throughout the project lifecycle.
  • Contributed fixes upstream to open-source software and worked across the full stack from hardware integration through production deployment.
  • Led architecture, implementation, debugging, and product decisions for independently operated systems.

Operational Leadership & Customer-Facing Responsibility

High-performance customer-facing industry

Staff training · Customer trust · Sales · Negotiation · Regulated responsibility · Public representation

  • Consistently among top performers in a highly competitive customer-facing environment, with documented results.
  • Trusted with legal and operational responsibilities on behalf of the company, requiring reliability, judgment, and compliance discipline.
  • Acted as one of the company’s primary public-facing representatives through extensive customer interactions.
  • Trained staff, managed expectations, handled high-value conversations, and translated customer needs into practical outcomes.

Approach

I prefer small systems with clear boundaries, deterministic output, low dependency surfaces, and behavior that can be inspected directly. A project is not finished until the infrastructure disappears into the workflow: version-controlled, tested, deployable, and maintainable through the next intended change rather than ongoing manual effort.

Technical Background

Long-running systems practiceProgramming since the late 1990s, including binary patching, DSP work for SHARC synthesizers, hardware/USB conversion, embedded firmware, networking, OpenBSD, and production web systems.