I built 2,000 badges for Replay and I’m not sure I’ve slept since December | Temporal

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Blog<br>Temporal Voices

I built 2,000 badges for Replay and I’m not sure I’ve slept since December

AUTHORS<br>Shy Ruparel

DATE<br>May 20, 2026

CATEGORY<br>Temporal Voices

DURATION<br>14 MIN

At some point in December, Candace, our Head of Design, asked me: what if your time at Replay could be represented as a Workflow? Every check-in, every fun event, every person you met, a living timeline, running on Temporal.

Four months later, I'm coordinating manufacturing circuit board badges in Shenzhen over WhatsApp at 11 p.m., and I've hand-soldered more PCBs than I'd like to admit.

To understand why I was asked to figure out this project is to know that my role at Temporal has this informal understanding baked into it: give Shy the weird projects. The ones that involve breadboards on a kitchen table at 11p.m, a document translation pipeline for toys. or a half-baked idea (or two, or three…) that could either be really cool or a complete disaster at a conference in front of 2,000 people.

The latter is this project where I sought out to create badges for Temporal's annual developer conference, Replay.

The concept stage#

Our Manufacturing Partners Elecrow, QAing our badge

I hit the ground running and started spec'ing it out. I could make one badge by myself, but to scale up to make a badge for everyone at Replay I knew I would need help. Through an introduction from some fellow recurse center alum, I found a hardware consultant and we put together a proposal.

Next, I had to pitch that proposal to Andrew Baker (our VP of Developer Relations) during his first five days on the job. Tricky because he didn't know me at all, but lucky for me, he trusted some DevRel guy with a hardware project budget that required convoluted manufacturing

The early concept drawings are genuinely charming to look at now.

Our hardware consultant's early sketches are full of hand-drawn illustrations of attendees holding a chunky handheld device with a T9 keyboard, an e-paper name tag on the front, a kickstand so it could sit on a table. There's even a little tamagotchi-esque character on the screen. The vision at that stage was something closer to a personal game console, or honestly a weird cell phone that only worked at Replay.

A hand-drawn illustration of the energy we've created for Replay

Then on to artistic inspiration. Our consultant came back with these stunning hand-drawn illustrations. It captures the spirit of what we were going for better than any spec doc ever could: it shows attendees gathered together, shrouded in a collective glow, illuminated by the feeling of knowledge and community. I'd even say the energy is even a little cosmic.

This is just the type of energy we've captured for the event as Replay is the community's conference. We just get the privilege of paying for it. Finding ways for attendees to interact, share moments, learn from each other, and spark something in each other is always ‌the actual goal. The badge is the vehicle taking you there.

What the badge does#

When you hear "badge," you probably picture a rigid little plastic thing with your name and an outdated LinkedIn headshot on it. Scrap that entire notion when we're talking about this badge because this one is more like a game piece.

Early prototype held in hand, screen showing "Alex Tideman / Design / Temporal" — a working dev unit

Attendees navigate Replay with a mission of gathering with their peers to traverse the cosmos of the development unknown. Along the way, they collect connections, unlock new levels, and even find hidden treasures all while the badge handles the infrastructure underneath.

So what's actually inside it?

The badge runs on an ESP32-S3 microcontroller with a 128x64 pixel OLED screen, an IR transmitter and receiver, a joystick, buttons, haptic feedback via a vibration motor, and an LED matrix with programmable colors.

Prototype B v0.0 schematic render

It also has a gyroscope, so the screen reorients depending on how you're holding it. Firmware is written in C, with a MicroPython layer sitting on top so attendees can write their own apps without needing to learn anything new. Attendees are able to update their contact information by using the MicroPython REPL and then beam it over to each other with the IR transmitter. The conference schedule is right there on the badge so you don't have to download an app (I don't know about you, but I've encountered very few conference apps that I've liked).

A clean green PCB with joystick and buttons, held at the factory in Shenzen, China

The Temporal-branded PCB, bare board with ESP32 chip

DELTA, our dev kit revision used for the majority of firmware development

Dev kit components laid out: DELTA units, batteries, cables

Final badge render, black with space motif, no screen...