I built a browser tool to reskin my DEF CON 34 badge lights

Last week at DEF CON 34 I got my badge running the rarest light pattern on the floor: a full-spectrum rainbow with the white “chaser” dot that only Uber badges get. This week I turned it into a browser tool any DC34 badge holder can use.

Open the DC34 Badge Light Studio »

What it does

Pick a scheme. Full rainbow in a few speeds, the Uber white-chaser, or warm, fire, cool, ocean, sunset, and purple palettes. A live preview animates the real 8-LED ring, so you see the look before you commit. Then hand it your badge’s nonce by pasting the text, uploading a photo of the nonce QR, or scanning it with your webcam, and it builds a QR. Put the badge in scan mode, point it at the code, keep the result.

Is this safe? Yes.

It touches nothing in your badge’s firmware. The light game encrypts its trades under one population-wide key that the badge team published, and bunnie’s own design assumed people would build tools like this. The whole thing runs in your browser. Each trade shows a keep-or-rollback prompt on the device, and your badge still converts to a FIDO2 security token. It reads no secrets and bricks nothing.

The fun part: badge genetics

The patterns work like a small genetic system. Trade with another badge and the two “genes” blend like DNA, with some traits winning over others. A wide color range and high saturation win their blend, so you can jump to a full-spectrum rainbow in a single trade. The white chaser wins the other way: a normal badge cannot breed into it in one shot. You seed it, keep the result, and repeat a few times until it sticks. The tool marks which schemes land in one trade and which take a few.

To keep the preview honest, I ported the badge’s real LED render code into the browser. You see how the ring computes hue, the moving brightness wave, and the sweeping white dot, from the same math the hardware runs. It stays approximate, since your badge blends the result with whatever it already carries.

Try it here. Not affiliated with DEF CON or Baochip. Built for badge holders who want to play with their lights.