Ask Hackaday: Did You Catch The Grammys?

Although award shows aren’t necessarily our thing, [T. D.] sent in something that piqued our interest. His friends recently got back from the Grammy awards where they witnessed thousands of LED bracelets blinking in time to a performance by Coldplay. A little bit of YouTubing pulled up this video that demonstrates the effect (because that video will probably be taken down shortly, just pick something from this link).

[T.D.]’s friends brought one of these bracelets back with them and like a good Hackaday reader, he cracked it open. This is the precious board pic that [T.D.] sent in. We’re pretty confident that the IC is an ATMega48PA, but beyond that we’re not quite sure how these bracelets can, “light up and flash at precisely the right time” as [T.D.] puts it.

From what we saw on the Grammy broadcast, it’s possible these bracelets merely flashed whenever the user clapped their hands. A circuit that simple doesn’t require a microcontroller, so we’re left wondering what the heck is going on here. If you’ve got an idea of how these choreographed light display bracelets work, drop a note in the comments.

EDIT: Commentors have pointed out these wristbands are called ‘Xylobands.’ There’s a great video of these wristbands in action at the 2011 X Factor finale.

82 thoughts on “Ask Hackaday: Did You Catch The Grammys?

  1. Ken, the code is most likely code protected and all you’ll get are the 0xFFs out of the flash space. Would not be smart by the manufacturer to ship out non-protected chips as once the code is dumped into a hex file, it’ll be easy to reverse-engineer and find bugs or worst clone the device. You’ll have to write your own; but in this case it’s much easier/faster/safer (patent wise) to write your own than reverse-engineering the code in the 8051. It’s just a LED strip that turns; it’s very simple.

  2. I stuck my key in an got it to flasks for a few seconds before turning out. Now I have a paper clip jammed into its gap and am able to turn it on and off at will. Stays on or stays off as long as my switch is set to the corresponding side.

    Now if only I could control it remotely as was the case at the Coldplay concert.

  3. Okay, despite this thread being pretty old, here’s an update: I recently got my hands on a V2.0-Wristband which is the one which uses an ATMEGA48. I’ve got almost complete schematics (correct values for the passive components are (still?) missing) as well as ASM-code and a backup of the EEPROM. I’ll receive two more wristbands within this week; if these are V2.0 as well, I might be able to look for differences in the EEPROM (the colour of the band is most probably stored there).

      1. jelmt: What do you mean with “write-up”? I can upload the schematics I extracted (it’s only scribbled on paper, though) and also pictures if you tell me what kind of pictures you want.

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