Notes on figuring out how to work with LLMs, from someone still figuring it out

Introduction

Every experience teaches you something. The only question is what.

Notes from my first job: research, teams, and the things that actually mattered

Things I Learned in 3.5 Years at my first job

A little bit of slope makes up for a lot of y-intercept

Control Wipro smart plugs programmatically using TinyTuya and the Tuya IoT platform, with an example battery-based charging automation script.

Automating Wipro Smart Plugs with TinyTuya

Set up instant, end-to-end encrypted Obsidian note syncing across all your devices using a self-hosted CouchDB server exposed via a Cloudflare Tunnel.

Self-Hosting Obsidian Live Sync with Cloudflare Tunnels

Guide for downloading HTML presentations as PDF files using DeckTape.

Converting HTML Presentations to PDF with DeckTape

How to configure a Jupyter notebook server to start automatically at system boot using systemd.

Creating a Systemd Service for Automatic Startup

DeckTape is a high-quality PDF exporter for HTML presentations, particularly useful when the built-in PDF export functionality doesn't work properly.
### Installation Steps

1. Install NVM (Node Version Manager):
```bash
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.1/install.sh | bash
```

2. Install Node.js:
```bash
nvm install node
```

3. Install Chromium browser (if needed):
```bash
sudo apt-get install chromium-browser
```

4. Install Chrome for Puppeteer:
```bash
npx puppeteer browsers install chrome
```

### Using DeckTape

1. Install DeckTape via npm:
```bash
npm install -g decktape
```

2. Convert a Reveal.js presentation to PDF:
```bash
npm exec decktape reveal --fragments https://iitm-pod.slides.com/arunprakash_ai/transformers-a-short-version/fullscreen dmd-dtx.pdf
```

3. For custom Chromium location:
```bash
PUPPETEER_EXECUTABLE_PATH=/usr/bin/chromium-browser npm exec decktape reveal --fragments https://iitm-pod.slides.com/arunprakash_ai/transformers-a-short-version/fullscreen lecture-1.pdf
```
### Notes  
- The `-fragments` option ensures all fragments (slide transitions) are included in the PDF
- For some Reveal.js presentations, you can simply add `?print-pdf` to the end of the URL
- DeckTape works for presentations where the built-in export fails
## References
- DeckTape GitHub repository: https://github.com/astefanutti/decktape

A guide to setting up instant, encrypted note syncing across all your devices using your own server -- no subscription required.

**Credit:** Steps roughly follow [this excellent Reddit thread](https://www.reddit.com/r/selfhosted/comments/1eo7knj/guide_obsidian_with_free_selfhosted_instant_sync/).

### What you'll need

- A Linux server (Ubuntu 24.04 used here)
- A domain managed on Cloudflare
- Docker and docker-compose installed

## Part 1: CouchDB Setup

```bash
mkdir -p ~/obsidian-livesync
cd ~/obsidian-livesync
```

Create `docker-compose.yml`:

```yaml
services:
  couchdb:
    container_name: obsidian-couchdb
    image: couchdb:3.3.3
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=Asia/Kolkata          # Change to your timezone
      - COUCHDB_USER=admin       # Change this
      - COUCHDB_PASSWORD=your-secure-password  # CHANGE THIS
    volumes:
      - ./data/couchdb/data:/opt/couchdb/data
      - ./data/couchdb/local.d:/opt/couchdb/etc/local.d
    ports:
      - "127.0.0.1:5984:5984"
    restart: unless-stopped
    healthcheck:
      # Must match COUCHDB_USER and COUCHDB_PASSWORD above
      test: ["CMD-SHELL", "curl -f -u admin:your-secure-password http://localhost:5984/_up || exit 1"]
      start_period: 120s
      interval: 30s
      timeout: 10s
      retries: 3
```

> **Important:** Update `COUCHDB_USER`, `COUCHDB_PASSWORD`, `TZ`, and the healthcheck credentials to match. The healthcheck password must be identical to `COUCHDB_PASSWORD`.

Start CouchDB:

```bash
docker compose up -d
docker compose logs -f
```

Wait ~2 minutes for CouchDB to be fully ready before continuing.

## Part 2: Configure CouchDB

Create an SSH tunnel from your local machine to access the admin panel:

```bash
ssh -L 5984:localhost:5984 username@your-server-ip
```

Open `http://localhost:5984/_utils` in your browser.

1. **Login** with your credentials
2. Click the **`<->`** icon (top left) to expand the menu
3. Click **Setup** → **Configure as Single Node**
4. Enter your admin credentials → **Configure Node**
5. Click **Verify** → **Verify Installation** (should show 6 checkmarks)

### Create the database

1. Click **Databases** → **Create Database**
2. Name: `obsidiandb`
3. Select: **Non-partitioned**
4. Click **Create**

### Add configuration

Click **Configuration** → **+ Add Option** for each of the following entries:

| Section       | Name                    | Value                                                      |
| ------------- | ----------------------- | ---------------------------------------------------------- |
| `chttpd`      | `require_valid_user`    | `true`                                                     |
| `chttpd_auth` | `require_valid_user`    | `true`                                                     |
| `httpd`       | `WWW-Authenticate`      | `Basic realm="couchdb"`                                    |
| `httpd`       | `enable_cors`           | `true`                                                     |
| `chttpd`      | `enable_cors`           | `true`                                                     |
| `chttpd`      | `max_http_request_size` | `4294967296`                                               |
| `couchdb`     | `max_document_size`     | `50000000`                                                 |
| `cors`        | `credentials`           | `true`                                                     |
| `cors`        | `origins`               | `app://obsidian.md,capacitor://localhost,http://localhost` |


## Part 3: Set Up Cloudflare Tunnel

Install `cloudflared`:

```bash
wget https://github.com/cloudflare/cloudflared/releases/latest/download/cloudflared-linux-amd64.deb
sudo dpkg -i cloudflared-linux-amd64.deb
```

Authenticate and create a tunnel:

```bash
cloudflared tunnel login
cloudflared tunnel create obsidian-sync
cloudflared tunnel list  # Note your tunnel ID
```

Create the config file:

```bash
sudo mkdir -p /etc/cloudflared
sudo nano /etc/cloudflared/config.yml
```

Paste this (replace `YOUR-TUNNEL-ID` and `yourdomain.com`):

```yaml
tunnel: YOUR-TUNNEL-ID
credentials-file: /root/.cloudflared/YOUR-TUNNEL-ID.json

ingress:
  - hostname: db-data-obsidian.yourdomain.com
    service: http://127.0.0.1:5984
    originRequest:
      noTLSVerify: true
  - service: http_status:404
```

Create the DNS record and start the service:

```bash
cloudflared tunnel route dns obsidian-sync db-obsidian.yourdomain.com
sudo cloudflared service install
sudo systemctl start cloudflared
sudo systemctl enable cloudflared
```

Verify it's working:

```bash
sudo systemctl status cloudflared
curl https://db-obsidian.yourdomain.com  # Should return CouchDB welcome JSON
```

## Part 4: Update CORS for Your Domain

Now that you have a public URL, add it to the CORS origins:

```bash
curl -X PUT http://admin:your-secure-password@localhost:5984/_node/_local/_config/cors/origins \
  -H "Content-Type: application/json" \
  -d "\"app://obsidian.md,capacitor://localhost,http://localhost,https://db-obsidian.yourdomain.com\""
```

## Part 5: Configure Your First Device (Desktop)

1. Download and install [Obsidian](https://obsidian.md)
2. Create a new vault
3. **Settings** → **Community plugins** → Enable community plugins
4. Browse → search **"Self-hosted LiveSync"** → Install and Enable
5. Open plugin settings → click the **satellite icon (🛰️)**

Enter these connection settings:

```
Remote Type: CouchDB
URI: https://db-obsidian.yourdomain.com
Username: admin
Password: your-secure-password
Database name: obsidiandb
```

6. Click **Test** -- should say "Connected successfully"
7. Click **Check** → **Fix** for any items without checkmarks
8. Click **Apply Settings**

**Enable end-to-end encryption (recommended):**

- Scroll to "End-to-end encryption"
- Toggle ON
- Set a passphrase -- remember this, you'll need it for every device
- Click "Just apply"

**Enable sync:**

- Click the **refresh icon (🔄)** (5th button)
- Sync mode: **LiveSync**
- Close settings

You should see "Sync: zZz" in the top-right corner of Obsidian.

## Part 6: Configure Additional Devices

Use the **Setup URI** method to avoid re-entering settings manually:

1. On your **already-configured device**:
   - Settings → Self-hosted LiveSync → click the **clipboard icon (📋)**
   - This copies a URI containing all your settings

2. On each **new device**:
   - Install Obsidian and create/open a vault
   - Install the Self-hosted LiveSync plugin
   - Open plugin settings → click the **satellite icon (🛰️)**
   - Click **"Use the copied setup URI"**
   - Paste the URI
   - Enter the **same encryption passphrase** as your first device
   - Click Apply

**Credits:** Thanks to [vrtmrz](https://github.com/vrtmrz) for the LiveSync plugin and the r/selfhosted community for sharing knowledge!
