Jesse
Jacobs

When people talk about RAG they usually picture a vector database, embeddings, and a complex pipeline. For small-to-medium knowledge bases, none of that is needed.

For both SouthStack and my portfolio the "RAG" is just: write a well-structured text file with everything the bot should know, paste it into the system prompt, and let Claude figure out what's relevant. Works fine up to ~50-100KB of text.

The trickier part was API key security. GitHub Pages can't store secrets, so I built a Cloudflare Worker proxy — 30 lines of JS that sits between the browser and Anthropic's API, reads the key from an environment variable, and forwards the request. Free tier covers 100k requests/day.

When you'd actually need a vector DB: hundreds of PDFs, a full documentation site, or a product catalogue with thousands of items. At that point Supabase pgvector or GCP Vertex AI Search become worth the complexity.

Modbus RTU is a serial protocol used in industrial sensors and PLCs. Simple in concept — master sends a request, slave responds — but getting it working reliably has a few gotchas.

The biggest issue was baud rate mismatch. Yosemitech Y510 sensors default to 9600 baud but the docs weren't clear. Getting libmodbus to connect required matching the baud rate exactly in modbus_new_rtu().

Cross-platform serial port handling in Qt was fiddlier than expected — Windows uses COM3 style names while Linux uses /dev/ttyUSB0. QSerialPort handles this but you need to enumerate available ports at runtime.

The traditional View-based approach for a live-updating sensor display means ViewModels, LiveData, RecyclerViews, and a lot of boilerplate. With Compose the entire sensor reading UI is maybe 60 lines.

A State object holds the current readings, a coroutine polls the sensor every 2 seconds, and the UI recomposes automatically. No notifyDataSetChanged(), no adapter pattern.

The Bluetooth/USB serial piece was harder — Android's USB Host API is verbose and the permissions model needs careful handling. The Modbus protocol itself runs fine over a USB-to-serial adapter using usb-serial-for-android.