Crowd Light Show is a free, open-source web app that turns a crowd's phones into one light show synchronized to the music.
The show flashes bright light. People with photosensitive epilepsy or sensitivity to flashing light should not take part. Flash rate is capped to no more than 3 flashes per second and large saturated-red strobing is blocked (per WCAG 2.3.1/2.3.2), but please use judgement. You can leave any time with the “Stop” button.
Taking part is anonymous — no account, no name, no email, no tracking cookies. If you enable the flashlight on Android, the browser asks for camera permission because that is how the web exposes the LED; no image is ever opened, recorded or sent — the camera is used only to switch the light on and off. Session data is discarded when the show ends.
Licensed under Apache-2.0. Source: github.com/AndriiShramko/crowd-light-show. You're free to use, run and modify it.
Free for any use. Want it customized, integrated, supported, or extended for your event/venue? Contact Andrii Shramko — LinkedIn · zmei116@gmail.com · book a call. Let's talk.
Music licensing for public performance is the organizer's responsibility (in Poland: ZAiKS and related societies).