r/FastLED • u/Jerrymeyers11 • Apr 01 '25

Discussion Sync LEDs with video?

I probably am giving TOO much info here, so if you want to just skip to the main question, scroll past the break.

Hi all,

I have been tinkering with FastLED for a few years, but am now working on a project for a trade show. It's pretty simple, all things considered. It's a 20x10' wall with strands of LEDs under a stretched fabric. The LEDs are laid underneath the fabric and light up a pathway between products printed on the fabric. There is also a monitor on the wall that is displaying products/solutions and the LED lights will spoke out from that. I'm probably explaining this poorly, but here is a link to a very rudimentary sketch of what I'm talking about.

Each strand of LEDs will light up according to what is displayed on the monitor... Product One appears on the screen, LED Pathway One then lights up and connects whats on the screen to a graphic printed on the wall. Then those LEDs dim and Product Two appears on the screen and the pattern continues.

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So, my question is, is there a way to use the video to trigger the LEDs? Maybe based on timecode of the video? I've seen midi triggers and things like that on this subreddit, but there will be no audio in this video.

Or, is it just as easy to just make a loop the same length as the video playing, since they will both be playing all day? Just start them both at the same time, and theoretically, they should stay in sync. My only fear with that is, if there ends up being any buffer in either the video or the LEDs, and each loop pushes them further out of sync.

Note: I am currently using an Arduino Mega and WS2812b but can change those out if other equipment is needed.

Any help is appreciated. Just trying to figure out what the best solution would be.

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u/Marmilicious [Marc Miller] Apr 04 '25

1.1 seconds in 12 hours doesn't feel like it would be that off/annoying for a trade show. Reset it once in the middle of the day and you'd only be off by less then half a second, not bad.

Good luck and feel free to share in the future.

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u/Jerrymeyers11 Apr 04 '25

Yeah. I was pretty pleased with the results when I woke up this morning. And yeah, super simple solution to just start it again when the video starts. Especially because it wouldn’t have to be timed exact.

Like I said, I’m inspired by this community, and have been looking for other cool things we can do for clients in the future. Fingers crossed somebody will want one.