Love this one! My immediate thought for a build: just a camera with on-device VLMs and LLMs. You could point it at a normal whiteboard (or a wall of sticky notes), and the model could interpret the handwriting, track the tokens, and sync the state digitally in real-time without needing any special "smart" hardware.
It feels like a much more flexible approach than an expensive proprietary whiteboard. Would a camera-only setup cover your use case?
The interface also allow to comment, post and interact with the original HN platform. Credentials are stored locally and are never sent to any server, you can check the source code here: https://github.com/GabrielePicco/hacker-news-rich.