Sandbar secures $23 million Series A to scale AI note-taking ring

Sandbar, a hardware startup founded by Mina Fahmi and Kirak Hong, has raised $23 million in a Series A funding round—a stage of venture capital financing used to scale early operations. The round was led by venture capital firms Adjacent and Kindred Ventures. This latest injection brings the company’s total funding to date to $36 million, following a previous funding round of $13 million raised last November. Sandbar currently has 15 employees and plans to use the new capital to double its software and machine learning teams, as well as hire marketing staff.

The startup’s primary product is the Stream, a smart ring worn on the finger that is dedicated to note-taking. Unlike health-tracking wearables, the Stream features a touch-sensitive panel and a microphone that is off by default. Notably, the microphone seems to be tuned for proximity, which requires the user to lift their hand to their face to record notes. Nico Wittenborn, an investor at Adjacent, noted that this physical action signals the intent of a private use case, distinguishing it from other note-taking devices that continuously record surrounding conversations.

Sandbar is positioning the Stream to support complex, iterative tasks rather than simple, one-off voice commands. The company has been working on the ring for over two years, including a testing phase with early adopters last year. According to co-founder Mina Fahmi, some users interact with the device over 50 times a day. Fahmi emphasized the necessity of conversational depth for the product’s utility: “Something that we think is necessary is back and forth conversation. Unlike a lot of experiences where you just say one command and it’s either transcribed or acted upon, like, via a smart speaker, Stream is really good at iterative tasks which begin, maybe in conversation or editing a note, but hopefully expand to multi-turn conversations, where you’re Claude Coding in your terminal and you are clarifying things [via voice]”

The company plans to start shipping the smart ring this summer. It enters a growing category of note-taking hardware, which includes competitors like Pebble, which aims to ship a $75 ring this year. To prepare for the launch, Sandbar is focusing on refining its mobile application, reducing model response latency, and eventually enabling agentic workflows—AI-driven processes where the system takes autonomous actions based on the user’s notes.

Why it matters

Sandbar is entering a growing category of hardware devices for note-taking, differentiating its Stream ring through a form factor designed for private use and a focus on agentic, multi-turn conversational workflows.