Start a swarm of these DIY Firefly LEDs a-blinking, and they'll create a random pattern and blink an angry red. But after a few minutes, thanks to some clever microcontroller code and a light sensor, they'll soon all be blinking in sync with a nice, calming blue color. It's a neat bit of DIY electronics that's elegant in its simplicity, and surprisingly cool to see in action on video. Even if you disturb their perfection with a flashlight, the system will eventually self-correct: The code works like this:

Each firefly has a value that stands for the power to flash. This value rises over time. If the power reaches a certain limit, the firefly flashes and the power is reset to zero. If the firefly detects another flash nearby, it increases the power by a small boost value. That way it will flash slightly earlier than last time. Doing so over and over again may lead to all fireflies flashing in sync.

For instructions on making your own, check out: [Tinkerlog via MAKE]