Buddy Beacon

Sometimes people are ambiently free to hang out, but it feels too heavyweight to keep texting around. I’ve also dealt with enough long rescheduling threads. I wanted something more organic, like college, when seeing a friend didn’t always start with making a plan.

So I made Buddy Beacon. Each light represents a friend. When they’re open to a visit, their light pulses. Pressing the button changes your own availability. The app lets you choose who’s on your beacon, their colors, and who can see you.

If you’re heading to a friend’s place, you can set that in the app. Your lights then share a color and pulse together on other friends’ beacons. But only if those friends are allowed to see both of you—otherwise, even a color could give away who you’re visiting.

You can also send a wave: a quick sweep of light around someone’s beacon, without changing your availability.

I started with hand-wired LEDs in a printed case, then had custom PCBs manufactured in China. Along the way, I worked on the enclosure, the board in KiCad, ESP32 firmware, a React app, and the backend that keeps everyone’s lights up to date.

I used software jigs a lot: small tools that let me correct AI’s work visually, then feed those corrections back into the design. For the lid, I could adjust the detected LED positions on a photo instead of trying to explain the mismatch in words. The second PCB version also fixes a too-tight ESP32 footprint and adds a level shifter for the LED signals.

I’ve worked on Buddy Beacon on and off since April 2026, and gave the first ones to friends in July. I want to see whether having them around makes it easier to hang out, and whether people keep using them.