Yang's Notes

1. First Principles: Endings, Middle-game and Openings

yang@yhu.me (Yang Hu) — Sat, 16 Jan 2021 16:16:44 -0800

Single pawn
#

The King should be in front of his Pawn, with at least one intervening square.
Advance the King as far as possible with the safety of the pawn, and never to advance the Pawn until it is essential to its own safety.

Other Pawn Endings
#

ℹ️ Don't push pawns prematurely

don’t push the pawn prematurely, which may send it to the opponent’s King, and you can’t protect it.

In this position, if white pushes the f-pawn, the game draws because ... Kf7. White is better to move his King and force the Black king to the corner, with help from g6 push, controlling the f7 square .

Imbalances and Bishop vs Knight

yang@yhu.me (Yang Hu) — Fri, 15 Jan 2021 22:17:41 -0800

Imbalances: the static and dynamic differences.

List of imbalances
#

Minor pieces: the interplay between Bishops and Knights
Pawn structure: doubled/isolated/backward/passed pawns, islands.
Space
Material
Files and squares: files, ranks and diagonals act as pathway, while squares act as homes.
Development: this is a temporary balance.
Initiative: also temporary.

⚠️ Don't look at individual moves!

Try to understand the position, before starting calculation on individual moves.

Bishop vs Knights
#

It’s the most important imbalance of the game.

The Center, Territory and Space

yang@yhu.me (Yang Hu) — Sun, 17 Jan 2021 23:18:05 -0800

Amateurs often have no clue of how to use center/space advantage, instead keen on forcing continuations, and unjustified attacks.

Rules of center
#

Rule 1. Full pawn center gives control and space.
#

A full pawn center gives its owner territory and control over key central squares.

Pawn Structure

yang@yhu.me (Yang Hu) — Sun, 24 Jan 2021 23:04:49 -0800

Knowning which pawn structure is “weak” is not enough: one need to know how to attack them, or making use of the weaknesses.

In general, the formular to attack weak pawns(isolated, backward) is to control the square in front of the pawn so it can’t advance. (the squares are usually weak since no pawn can defend it). Then pile up on the weakness.

Every structure has its pros and cons.

4. General Theory

yang@yhu.me (Yang Hu) — Sat, 16 Jan 2021 22:12:23 -0800

Lichess study of this chapter
#

Embedded chessboard from lichess.org

The initiative
#

White has the move, which means initiative. He tries to first control the center, or obtain some positional advantage, so it’s possible for him to keep on harrassing the enemy.

He only relinquishes the initiative when he gets for some material advantage in return.

5. End Game Strategy

yang@yhu.me (Yang Hu) — Sat, 16 Jan 2021 22:26:15 -0800

Lichess study of this chapter
#

Embedded chessboard from lichess.org

The sudden attack from a different side
#

Similar to general theory, the idea is to first attacking on one side, then, with greater mobility of the pieces, quickly transfer attack to the other side and break through, before the opponent can respond.

Fixing a Camera Crash Cascade: How an LLM Health Check Found a Hidden Frigate Bug

yang@yhu.me (Yang Hu) — Fri, 03 Apr 2026 00:00:00 -0800

A daily LLM-powered health check flagged that 8 out of 10 cameras had crash counts in the hundreds. The root cause turned out to be two baby monitor cameras, a go2rtc reconnect window, and a vaapi cascade failure — none of which were directly obvious. Here’s how we found it and fixed it.

How the Issue Was Found
#

I’ve been building a daily home health agent — a scheduled script that queries all home services (Frigate, Home Assistant, Paperless, the arr stack) and passes the data to a local LLM for analysis. The idea: instead of manually checking dashboards, get a morning summary that flags anything unusual.

Claude Code WSL Notifications with WezTerm Focus

yang@yhu.me (Yang Hu) — Tue, 24 Mar 2026 00:00:00 -0800

When running Claude Code inside WSL, it’s easy to miss when it’s waiting for your input — especially if you’ve switched to another window while it works. This post documents the notification system I set up: Windows toast notifications that fire when Claude stops and when it needs permission, with click-to-focus on the exact WezTerm pane.

How It Works
#

Claude Code has a hooks system in ~/.claude/settings.json. Two events are useful here:

Switching Frigate to YOLOv9t with OpenVINO on Intel N97

yang@yhu.me (Yang Hu) — Thu, 19 Mar 2026 00:00:00 -0800

Replacing Frigate’s default SSD MobileNet detector with YOLOv9t (tiny) running on the Intel N97’s integrated GPU via OpenVINO. Covers model export, correct Frigate config, and a critical gotcha that causes 100% false positives if you get it wrong.

Setup
#

Server: Intel N97 (Debian 13), 8 camera streams
Frigate: 0.17, running in Docker
Detector: OpenVINO GPU (/dev/dri/renderD128)
Previous model: SSD MobileNet v2 (built-in, 300×300)
New model: YOLOv9t ONNX (320×320, 8.3 MB)

Why YOLOv9t?
#

The default SSD MobileNet v2 bundled with Frigate’s OpenVINO image is fast and lightweight, but accuracy suffers on partially occluded objects and objects at the edges of the frame. YOLOv9t (tiny) offers meaningfully better detection quality with a similar computational footprint — at 320×320 input and ~18ms inference on the N97 iGPU, it handles 8 concurrent camera streams comfortably.

Frigate NVR Setup: From Docker to HA Notifications

yang@yhu.me (Yang Hu) — Wed, 18 Mar 2026 00:00:00 -0800

Setting up Frigate NVR on a dedicated Debian server (Intel N97) to replace a traditional NVR. Covers Docker compose, go2rtc stream config, hardware acceleration, HA integration, push notifications, and zone-based alerting. Traffic between VLANs goes through the main router (UCG Ultra).

Hardware & Context
#

Server: Intel N97 mini PC (debian.lan, 10.0.10.11), Debian 13
Cameras: 8 Reolink PoE cameras on camera VLAN (10.0.40.0/24), 2 Nanit monitors on IoT VLAN (10.0.20.0/24)
Existing NVR: kept running for continuous recording; Frigate handles detection and event clips only
Home Assistant: on IoT VLAN (10.0.20.10), MQTT broker already running

Storage Design
#

Frigate recordings go to a dedicated NAS share — no local NVMe waste for surveillance video.

AI-Powered Document Classification with paperless-ai and Ollama

yang@yhu.me (Yang Hu) — Thu, 12 Mar 2026 00:00:00 -0800

This post is a complete runbook for integrating AI-powered auto-tagging and classification into paperless-ngx using paperless-ai and a locally-running Ollama instance. The setup uses a local LLM to read document text and automatically populate metadata fields — title, document type, tags, correspondent, date, and custom fields.

Hardware and Architecture
#

NAS (Synology DS1621+, 10.0.10.10): runs paperless-ngx on port 5656
Desktop PC: Windows with WSL2, Docker Desktop, RTX 4090
Goal: AI auto-tagging/classification using a local LLM, zero cloud dependency

The key architecture decision is a pull model: paperless-ai runs in WSL2 Docker, polls the paperless-ngx API for documents tagged ai-pending, processes them with Ollama, and writes metadata back. This is the correct approach for a desktop that is not on 24/7 — the NAS holds the queue and the desktop drains it when available.

Organizing Local Lecture Videos in Plex with Proper Metadata

yang@yhu.me (Yang Hu) — Thu, 12 Mar 2026 00:00:00 -0800

How to structure local lecture/course videos (without an official TMDB/TVDB entry) in Plex as a proper TV Show with seasons, episode titles, and custom descriptions set via the Plex API.

The example here is Jonathan Biss’s Exploring Beethoven’s Piano Sonatas — a 5-part Coursera course from the Curtis Institute of Music, stored on a Synology NAS.

The Problem
#

Plex’s default scrapers rely on TMDB or TVDB. Local lecture videos with no database entry either show up as a mess of unmatched files, or get incorrectly matched to something unrelated.

AirPrint on Synology NAS via CUPS Docker

yang@yhu.me (Yang Hu) — Wed, 11 Mar 2026 00:00:00 -0800

Runbook for setting up AirPrint on a Synology NAS so iOS/macOS devices can print to a USB or network printer over the local network. Uses a Docker CUPS container and Synology’s built-in avahi (mDNS) daemon for service discovery.

Architecture
#

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iPhone
 │ mDNS discovery (_ipp._tcp)
 ▼
Synology avahi-daemon (eth4, port 5353)
 │ reads service files from /etc/avahi/services/
 │
CUPS Docker container (host network, port 631)
 │ generates /etc/avahi/services/AirPrint-*.service
 │ proxies print jobs to printer
 ▼
Printer (e.g. socket://10.0.20.50:9100)

Key design decisions:

Paperless-ngx: Migrating a Decade of Documents from Google Drive

yang@yhu.me (Yang Hu) — Wed, 11 Mar 2026 00:00:00 -0800

Runbook and design journal for migrating ~400 personal documents from a folder-based Google Drive system into Paperless-ngx on a Synology NAS. Covers taxonomy design, bulk import from Google Takeout, ML classifier setup, and ongoing intake workflow.

Problem Statement
#

For years my “document management” was a manually maintained folder tree on Google Drive:

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10 - 文书材料/
 10 - 证件材料/身份证件/
 30 - 移民文档/
 30 - Tax Filing/
 40 - Finance/
 50 - 车辆注册/
 60 - 住房买房/
 80 - Medical/
20 - 家装住房信息/
80 - 旅行计划/

This worked well enough for filing but poorly for retrieval. Finding “what insurance forms did I have in 2022?” meant navigating six folders and guessing what I named things. Paperless-ngx offers full-text search, OCR, and an ML classifier that learns from your own labeling — a meaningfully better system for a document archive that spans immigration paperwork, tax filings, mortgage docs, and medical records across 10+ years.

Synology Photos → Immich Migration Runbook

yang@yhu.me (Yang Hu) — Mon, 09 Mar 2026 00:00:00 -0800

Personal runbook for migrating a family photo library from Synology Photos to a self-hosted Immich instance. Covers bulk upload, Google Takeout import, and album reconstruction via the Synology PostgreSQL database.

Setup
#

Source: Synology NAS running Synology Photos (multiple users)
Destination: Immich self-hosted on the same NAS
Upload tool: immich-go v0.31+
Client: WSL2 on Windows, SSH access to NAS
Album script: custom Python (migrate_albums.py) using Immich REST API

Phase 1: Photo Uploads
#

Strategy
#

Two sources per user:

Sleep Training for Months 3-4

yang@yhu.me (Yang Hu) — Thu, 16 May 2024 21:44:33 -0700

Four Month Sleep Regression
#

New sleep cycle with 5 different stages

REM: Dreaming sleep
Stage 1: very light/drowsy sleep
Stage 2: Light sleep
Stage 3/4: Deep restorative sleep

Light sleep almost every hour or two throughout the night. They need to learn how to go back to sleep after the light/wake stage.

The 7-step guide

Fill the tank
Check the engine
Set the cruise control
Top off the tank
Hit the brakes
Plan your rest stops
Unload the baggage

1. Fill the tank
#

Maintaining adequate feedings during the day.

Sleep Training for the Toddler

yang@yhu.me (Yang Hu) — Sat, 11 May 2024 22:41:36 -0700

Prepare the little one
#

B-E-S-T
#

B - Building confidence: talk about “good” things about sleep. 可以表扬他们睡的很好，或者跟他们说自己睡的好，变强壮了，etc. 产生正面影响
E - expectations: 明确表达你对他们的期望，希望他们做什么。 “I’m going to give you lots of kisses, and you’re going to lay down on your bed, close your eyes and have a good sleep. "

Neovim Workflow

yang@yhu.me (Yang Hu) — Tue, 07 May 2024 12:58:05 -0700

Neovim comes with lots of useful plugins, and built-in features, compared to Vim. It’s lua configs is also much more readable and powerful compared to Vim. Here’s some useful tips for coding in Nvim.

Searching(files, text, diagnostics, help)
#

Similar to techniques mentioned in search-in-vim, we can search for text inside files, or looking for files by filtering filenames. In Neovim, we use fzf-lua which is very similar to fzf.vim.

Search in Vim

yang@yhu.me (Yang Hu) — Sun, 09 May 2021 11:33:39 -0700

搜索是开发中最常用也是最重要的操作之一. Vim提供了非常高效和方便的搜索功能. 这篇笔记记录了一些常用的搜索命令,例子以及自定义的key mapping

使用ripgrep搜索文件内容 (:Rg2 or ,gg, ,gw/,gW )
使用git-grep搜索git branch/commit, 以及使用fzf显示git grep的结果 (:Ggrep)
使用fzf/coc list搜索当前文件/buffers中的lines, 实现快速定位/跳转
使用quickfix lists快速访问上述搜索的结果, 以及利用:cdo/:cfdo等命令对结果进行批量操作.

General searching inside files
#

Ripgrep with fzf
#

fzf.vim provides a :Rg command to call ripgrep and search the current directory. However, a more useful variant is built to support specify path and pass other parameters to ripgrep, I used this snippet and mapped this to shortcut <Leader>gg.

Vim Tips

yang@yhu.me (Yang Hu) — Thu, 15 Apr 2021 00:01:16 -0700

Search and work with many files
#

Searching
#

For searching words / symbols within files, see search-in-vim

To quick find and open files by filename, I use fzf and coc-list, and the follwing key bindings.

General search

To open files in the working directory ( not current file/buffer dir), use :Files or ,lc ( list current)

Keyboard Pcb Design

yang@yhu.me (Yang Hu) — Sun, 11 Apr 2021 18:37:25 -0700

Feature highlights
#

Initially, I wanted to build a split board. However, since I already have a split (crkbd), making a Arteus/Reviuge-like board makes more sense.

The design is using aggressive stagger (same column stagger like my split design), and 15 degree angle of columns.

Other features:

OLED status display
RGB underglow
Audio
Encoder

Design considerations for STM32
#

I’ll be using F411 due to lack of F072 stock.

Yang's Notes

1. First Principles: Endings, Middle-game and Openings

Single pawn #

Other Pawn Endings #

Imbalances and Bishop vs Knight

List of imbalances #

Bishop vs Knights #

The Center, Territory and Space

Rules of center #

Rule 1. Full pawn center gives control and space. #

Pawn Structure

4. General Theory

Lichess study of this chapter #

The initiative #

5. End Game Strategy

Lichess study of this chapter #

The sudden attack from a different side #

Fixing a Camera Crash Cascade: How an LLM Health Check Found a Hidden Frigate Bug

How the Issue Was Found #

Claude Code WSL Notifications with WezTerm Focus

How It Works #

Switching Frigate to YOLOv9t with OpenVINO on Intel N97

Setup #

Why YOLOv9t? #

Frigate NVR Setup: From Docker to HA Notifications

Hardware & Context #

Storage Design #

AI-Powered Document Classification with paperless-ai and Ollama

Hardware and Architecture #

Organizing Local Lecture Videos in Plex with Proper Metadata

The Problem #

AirPrint on Synology NAS via CUPS Docker

Architecture #

Paperless-ngx: Migrating a Decade of Documents from Google Drive

Problem Statement #

Synology Photos → Immich Migration Runbook

Setup #

Phase 1: Photo Uploads #

Strategy #

Sleep Training for Months 3-4

Four Month Sleep Regression #

1. Fill the tank #

Sleep Training for the Toddler

Prepare the little one #

B-E-S-T #

Neovim Workflow

Searching(files, text, diagnostics, help) #

Search in Vim

General searching inside files #

Ripgrep with fzf #

Vim Tips

Search and work with many files #

Searching #

Keyboard Pcb Design

Feature highlights #

Design considerations for STM32 #

Single pawn
#

Other Pawn Endings
#

List of imbalances
#

Bishop vs Knights
#

Rules of center
#

Rule 1. Full pawn center gives control and space.
#

Lichess study of this chapter
#

The initiative
#

Lichess study of this chapter
#

The sudden attack from a different side
#

How the Issue Was Found
#

How It Works
#

Setup
#

Why YOLOv9t?
#

Hardware & Context
#

Storage Design
#

Hardware and Architecture
#

The Problem
#

Architecture
#

Problem Statement
#

Setup
#

Phase 1: Photo Uploads
#

Strategy
#

Four Month Sleep Regression
#

1. Fill the tank
#

Prepare the little one
#

B-E-S-T
#

Searching(files, text, diagnostics, help)
#

General searching inside files
#

Ripgrep with fzf
#

Search and work with many files
#

Searching
#

Feature highlights
#

Design considerations for STM32
#