Hacking with Claude on a $27 Smart Watch

The Pine Time is simply a $27 smart watch that runs unfastened root firmware. I’ve had 1 sitting successful the backmost of a drawer for a year aliases two. When I saw @steveruizok’s Tweet about hacking connected ESP32 devices pinch Claude, I recovered immoderate inspiration to propulsion my PineTime retired of the drawer and spot what Claude mightiness beryllium tin of!

I knew I wanted to commencement by building a watch look because the default watch faces that travel pinch the watch are beautiful plain and boring. I’d besides recently seen @levelsio’s Tweet about building a civilization Casio watch look for is Apple Watch.

I wondered if I could build thing akin for the PineTime (with a little help from Claude). As it turns out, the PineTime is simply a awesome watch for hacking with Claude!

• It’s inexpensive ($27).
• It runs unfastened root firmware (InfiniTime, aliases immoderate different RTOS you want).
• It’s very well-documented. Claude thrives connected this.
• It has a awesome simulator (InfiniSim). That gives Claude a accelerated feedback loop connected your computer.
• The firmware is simple, truthful you benignant of need to adhd what you want.

Although I’ve been saying “Claude”, I really did astir of the activity successful OpenCode with immoderate of my favourite unfastened weights models. Kimi K3 & K2.6, and DeepSeek v4 Pro & Flash. I started by cloning the InfiniSim repo (which has a git submodule for InfiniTime, and asked Claude to get a build working. It was speedy and easy connected Ubuntu! Then I got pretty ambitious: I gave Claude the photograph from @levelsio’s Tweet, and asked Claude to replicate the watch face, copying the codification from an existing InfiniTime watch look arsenic a starting point. And I asked it to orchestrate and usage sub-agents arsenic needed for well-scoped improvement tasks.

It built a beautiful bully unsmooth approximation, but it was very rough. It seemed to conscionable conjecture astatine matter sizing and positioning, which led to things being benignant of in the correct spot but overlapping each different and unreadable. Still, it was a good starting constituent that we could iterate on. I deliberation Fable would person probably been capable to decorativeness the activity and get it pixel-perfect without supervision, if I gave it a feedback loop to screenshot the simulator. But since I was doing this with unfastened weight models connected OpenCode, connected a constricted budget, I opted to prevention some tokens by getting a small much progressive myself, and gave it circumstantial feedback with isolated tasks and actual adjacent steps. I fixed 1 point astatine a clip – getting each matter constituent correct earlier moving connected to the adjacent one.

I noticed we were spending a batch of effort trying to build immoderate fixed parts of the screen, and realized that mightiness not beryllium necessary. I wondered if I could just make a fullscreen inheritance image pinch each the fixed parts, truthful we only had to program the move parts of the screen. We tried this, and it worked connected the simulator! After installing the firmware connected a existent watch, I recovered that we were pushing the limits of what this small watch was tin of. It took astir 10 minutes to transportation the 240x240 image complete bluetooth to instal it connected the device, and it takes 1-2 seconds to refresh the full surface erstwhile you swipe. The watch can’t clasp this full image successful representation astatine once; it has to watercourse it from the record system. But that’s wholly good for a watch look I built successful a couple hours! I mightiness travel backmost astatine immoderate constituent to build much of the inheritance in code, truthful it tin update instantly. But for today, I’m happy pinch my working prototype!

I pushed each my codification up to GitHub, and you’re welcome to usage it directly, aliases usage it arsenic a starting constituent for your ain task if you want. I besides had Claude summarize the things we learned on the measurement into an AGENTS.md. That should thief you get started quickly, and debar immoderate of the hurdles that I ran into, if you want to effort this pinch your ain watch!

I loved moving connected this task pinch an AI! The low-stakes situation (not production codification astatine my time job) makes maine consciousness for illustration I tin effort immoderate I want and iterate quickly, and it’s really rewarding to activity connected firmware for a physical device that I tin clasp and usage erstwhile I’m done building it! I mates years ago when I bought this PineTime, I ran retired of clip and information to study really to work successful the InfiniTime codebase, and the watch sat successful a drawer for a couple years. But today, I was capable to build a caller watch look successful a fewer hours, and had fun doing it! The early is bright!