Random writings on Định Nguyễn

ClauBlink — A Physical LED That Blinks When Claude Is Thinking

Tue, 14 Apr 2026 14:00:00 +0700

TL;DR

I built a physical LED indicator that shows what Claude Code is doing in real-time. Fast blink means it’s streaming a response. Slow blink means it’s thinking. Solid green means it’s done. Works over USB serial and WiFi, supports two boards (ESP32-C3 and RP2040), and hooks into Claude Code’s event system with a 56-line shell script.

GitHub: github.com/dinhnguyen/ClauBlink

Why

I run Claude Code sessions that sometimes take a while. At home, I don’t want to sit there watching the terminal. I want to step away, play with my kid, do something else. But checking my phone for notifications isn’t great either, because if I’m playing with my son, I’m playing with my son, not staring at a screen.

Roll the Dice — When Your Kid Needs a Dice and You Have a Terminal

Sun, 12 Apr 2026 17:00:00 +0700

TL;DR

My son wanted to play a board game. We only had one physical dice. Instead of going to find more, I opened Claude Code and built a web dice roller with 3D animations, 10 random dramatic soundtracks, and a competitive scoring mode. The whole thing took about 30 minutes.

Live: dice.dinhnn.com

Fun fact: while writing this post I learned that the correct singular form of “dice” is actually “die.” But this is a fun post about rolling dice with my kid, not a grammar exam. So “one dice” it is. 🎲

Jira Report — A Tiny Tool for People Who Don't Want to Learn JQL

Sat, 11 Apr 2026 12:00:00 +0700

TL;DR

I built a small Jira report tool that answers one question: what did the team work on in a given period? You pick boards, pick dates, get a table. Nothing more.

JQL can already do this. But JQL has a learning curve, and most people on a team don’t have the time or interest to write queries. So I built a form.

Live: jira-report.dinhnn.com

The Problem

Every sprint review, every weekly sync, every 1:1 — someone asks the same question.

Building py-player — A Media Player Nobody Asked For

Fri, 10 Apr 2026 00:00:00 +0700

TL;DR

I built a dependency-free Web Component media player with 7 layout presets, 7 themes, audio visualization, and i18n. Nobody asked for it. I’m not sure anyone needs it. But I built it anyway, with Claude Code doing most of the heavy lifting.

Docs & Playground: py.dinhnn.com

GitHub: github.com/dinhnguyen/py-player

npm: npm install py-player

An Idea That Sat Around for Years

I’ve wanted to build a custom media player for a long time. Not because the world needs another one — HTML5 <audio> and <video> have gotten really good. The native controls work fine for most people. The ecosystem of existing players is mature. There’s howler.js, plyr, vidstack, and dozens more.

When a Bad Custom Module Breaks Odoo 's Attendance — And You Have to Fix It in Yours

Thu, 09 Apr 2026 00:00:00 +0700

Note: This is a personal log of what I ran into while vibe-coding an Odoo integration with Claude. Some of the approaches and assumptions here may not be correct if you have more professional Odoo experience than I do. Take it as a war story, not a best practice guide.

TL;DR

Odoo 18’s core hr_attendance module works fine. The overtime computation, the unique constraint, the _update_overtime() logic — all correct. The problem? A third-party custom module that overrides create() and write() on hr.attendance without understanding the side effects. It triggers _update_overtime() multiple times for the same day, causing a duplicate key violation. Your attendance record gets rolled back. The employee’s scan vanishes.

Building QR Forest — Hiding QR Codes Inside 3D Pixel Art Forests

Mon, 06 Apr 2026 00:00:00 +0700

TL;DR

I built a web app that generates scannable QR codes disguised as pixel art forests. The trick: looking straight down through the tree canopy, the gaps between leaves form a valid QR pattern. Switch to 3D and it becomes a tiny voxel garden with trees, flowers, and seasonal particles. Built with Next.js 16, Three.js (React Three Fiber), and a lot of BoxGeometry.

Try it: qr-forest.dinhnn.com

The Idea

It started with a 3D render I saw on Threads — someone had made a scene where you could switch the camera from a flat QR code view to a beautiful 3D garden. The transition was mesmerizing. I wanted to build that.

Cloudflare Workers Subrequest Limit — Post-mortem

Fri, 03 Apr 2026 00:00:00 +0700

TL;DR

Deploying a Jira time-report API on Cloudflare Pages (Workers edge runtime) caused silent data loss for 25 out of 57 issues. The root cause was Cloudflare Workers’ 50-subrequest-per-invocation limit on the free tier. Fixed by embedding worklogs in the JQL search response instead of making separate API calls per issue.

The Problem

When selecting all 9 Jira boards on the time report page, team member “Ngọc Định Nguyễn” showed 8h instead of the correct 30.5h. Selecting only boards 36+37 showed the correct value.

What?

Fri, 13 Oct 2023 12:21:57 -0500

What :)