About SWYoon Labs

SWYoon Labs is the engineering notebook and product hub of swyoon, a software engineer who builds practical browser tools and is learning hands-on electronics in public.

The common thread is simple: build something useful, measure what actually happens, and explain the decisions clearly enough that another beginner or developer can reproduce the result.

What this blog is for

This is where I publish:

  • Practical electronics guides — multimeters, breadboards, voltage dividers, Arduino, and Raspberry Pi
  • Chrome extension engineering — Manifest V3, side panels, local-first storage, accessibility, and testing
  • Product walkthroughs — how to use the tools I build and why particular features exist
  • Build notes — mistakes, measurements, trade-offs, and the reasoning behind a working result
  • Release notes and troubleshooting — meaningful changes and solutions to common problems

I write in English here. My Korean company site and selected Korean engineering notes live at won-solution.com.

Start here

If you are moving from software into electronics, begin with my hardware-learning roadmap, continue with the digital multimeter guide, and then build the loaded voltage-divider experiment.

If you build browser extensions, start with how I built a Chrome extension with AI or the dual-state calculator design.

My Chrome extensions

Extension What it does
Simple Side Note A notepad that lives in the Chrome sidebar — take notes without switching tabs
Phrase Hero Learn English phrases and idioms with short, frequent quizzes
Side Panel Clock A clock, world clock, timer, and Pomodoro for the browser sidebar

All extensions are built with privacy in mind: no accounts, no servers, no tracking. Your data stays on your device.

How I work

For software, I favour small, inspectable implementations and document the state models, failure cases, and privacy decisions behind them. For electronics, I calculate first, wire at extra-low voltage, measure with a digital multimeter, and distinguish predicted values from real observations.

The full source code for the open-source projects is available on GitHub. Circuit illustrations on this blog are created specifically for the accompanying articles.

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Last updated: September 2026

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