Vibe Coding for the Pebble Time 2: How I built a native C app using AI Agents and Codespaces.

The Pebble is back. I used Gemini 2.5 and GitHub Codespaces to have an app ready for Day One.

The news is out: The Pebble is back. Core Devices just announced the Pebble Time 2 (shipping December 2025). It’s 64-color e-paper, open-source, and has a 30-day battery life.

I couldn’t wait for the hardware to arrive to start building. But I also didn't want to spend weeks learning memory management in C or fighting with local toolchains.

So, I treated this as a "Vibe Coding" experiment.

I wanted to see if I could use modern AI agents to bridge the gap between my product ideas and the bare-metal constraints of the native Pebble SDK.

The "Hacker" Stack

This wasn't built the traditional way. I used a completely cloud-based, AI-driven workflow:

• The Environment: GitHub Codespaces. I spun up the legacy Pebble SDK in a cloud container. No local installation, no "it works on my machine" issues. Just a browser tab and a terminal.
• The Engineer: Gemini 2.5 Agent. I am not an embedded C expert. I used Gemini as my autonomous coding agent. I defined the vibe (functionality, UI logic, memory constraints), and the agent handled the syntax, pointers, and memory allocation.
• The Target: Native Pebble SDK. We didn't use a wrapper. This is raw C code optimized for the 200x228 resolution of the new Time 2.

The Result: Vocab Learner

The result is Vocab Learner, a distraction-free vocabulary trainer designed to live on your wrist.

• Passive Learning: Auto-advances to a new GRE-level word every 10 minutes.
• Deep Data: Cycles through phonetics, etymology, and examples.
• Efficient: The whole thing runs on a ~2.4KB RAM footprint.

Why I did this

We are entering a new era of "Hackability." The new Pebble watches run PebbleOS, which is now open source. Combined with the power of AI Agents, the barrier to entry for building embedded apps has never been lower.

You don't need to be a C wizard anymore; you just need an idea and the right agent.

The code is open source. If you are waiting for your Pebble Time 2, fork this repo. Let's see what else we can "vibe code" into existence before the hardware ships.

[Link to GitHub Repository]

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