我有一隻 GARMIN，所以我用 Claude Code 試著寫了一個錶面，以下是我學到的東西。 I Have a GARMIN Watch, So I Tried Building a Watch Face with Claude Code—Here's What I Learned

Some important notes before we begin:

1. For watch faces only, you just need to register as a developer on GARMIN’s Connect IQ (same account as your watch). You can keep it in Preview status (for the app).
2. Capturing screenshots from the watch on Mac is a bit troublesome—you need to download a file manager that supports MTP protocol, such as OpenMTP.

The main purpose of this article is to document my development journey.

Initially, I just wanted to test Claude’s AI capabilities, and I happened to have a one-month Pro trial, so I started this small project. I didn’t expect to be able to create a working watch face in about 8 hours of work, especially since I had never written any Garmin programs before.

When I officially started, I first checked Garmin’s developer website to understand the required specifications. For example, I had never touched Monkey C, but it was described as similar to Java. I also needed to install Garmin’s SDK program. None of this was a major issue.

OK, then the project began. First, I created a folder and initialized the project using the official documentation’s init command, then asked Claude if it could help me start writing a Garmin watch face. Its performance was quite good—it quickly detected what the project was about and what was needed.

But since this was a completely new project, Claude couldn’t write something complete at first. This is normal.

So I started searching online for similar open-source project documentation, preferably more complete watch faces. I eventually found similar projects, and the official Garmin team had actually released example watch face projects.

I didn’t carefully examine what was inside these two projects. I just threw them into the project, creating an example folder for Claude to use as reference.

And this is where I found it amazing—Claude was actually able to read the architecture of both example projects, give me references for features I wanted to implement, and write them directly.

From here, the project started moving faster. I could run the Garmin Simulator locally and see some results.

This is where the real work began.

Drawing content on an MIP screen is not simple, especially since my watch is the Instinct 3. Its screen shape is not a perfect circle (or maybe it is—I haven’t checked), and there’s a circular area in the upper right corner. If you look closely, you can see that the circular division is just a black overlay printed on top of the screen to mask it.

The most troublesome part is that the official watch face display seems to be slightly misaligned. I’m not sure if this is Garmin’s quality control or another reason, but in any case, positioning content on the screen became the first difficulty in making the watch face. So I experimented many times with how big the circular area should be and how to adjust its position.

I told Claude that I needed a setting that would allow me to offset objects inside the circle vertically and horizontally.

Next was the watch face content. First, I displayed the time. When I wanted to further adjust the displayed text, I discovered that text on the watch face can use specially processed fonts—Bitmap Fonts. The method is to output text as transparent PNG images, which are then displayed on the screen. According to the AI, this saves more memory.

I experimented once with displaying a Matrix-style falling text animation and ASCII art on the watch face. However, once the amount of text reached a certain level, the watch’s display refresh rate slowed down. From then on, I realized that the displayed content needs to be carefully optimized.

I asked the AI several questions in succession: MIP screen display technology, how to make the digital screen respond faster, and how to use custom fonts, among other questions.

Here I think Claude’s response was quite outstanding. I had only used Gemini and the free Grok-code-fast-1 before, and Claude’s behavior felt more comprehensive—it would proactively search online and provide more complete explanations (accuracy aside, since I was just trying to build a prototype first).

For example, in the “custom fonts” area, it even suggested I download Roboto to try first. Of course, this didn’t work on the first attempt, so it gave me the Garmin website and taught me how to convert fonts (by the way, using Windows for conversion is more convenient).

In summary, my experience using Claude was very good—surprisingly good. Whether it was architectural questions, usage issues, or even problems I didn’t know I had, I could ask Claude to explain them. At least for this watch face project, the explanations often solved my problems, and I repeatedly hit the PRO tier rate limit, which shows how much I relied on it. Whether it was updating the README or technical documentation, I was thoroughly impressed.

You could say that no matter what problem you have, subscribing is probably the right choice 80% of the time. Just remember to give Claude enough information to help you sort through the project content.

In the end, will I complete this watch face project? Probably not, because Claude has already helped me quickly build this prototype, and I’ve come to realize that further refinement—such as fixing alignment issues with watch face elements and testing battery consumption, which I haven’t yet addressed—would require a tremendous amount of time.

For example, the official watch face I currently prefer displays a lot of information. It must use various techniques to quickly refresh the display and make tradeoffs. I think the development time is measured in months. No wonder community-built watch faces tend to have simpler designs.

I can better understand why GARMIN’s product line switched to AMOLED, although I really love the digital watch feel of MIP and the solar charging function.

Also, the Watchface Builder project online (https://garmin.watchfacebuilder.com) I can now truly appreciate how amazing it is. The creator is a genius.