These DIY LED Party Bracelets Sync Animations via Wireless Mesh Networking

If you were at a big arena concert a couple of decades ago and the band played a ballad, you would have seen the stands light up with the flickering flames emitted by thousands of lighters. But not many people carry lighters these days and all of that fire was probably a bad idea anyway. Illuminated smartphone screens are sometimes seen as a modern alternative, but that’s just depressing. The real magic comes from connected LED wearables and Barney Nicholls has an awesome tutorial that will walk you through making your own LED bracelets that synchronize via wireless mesh networking.

Nicholls got this idea after seeing similar bracelets at the Glastonbury Festival. There, attendees were issued bracelets to wear. They would all synchronize together, playing various animations and effects. They could also respond to what was happening on stage, doing things like reacting to the music. That is a pretty cool successor to the old “hold up your lighter” thing.

When Nicholls saw that, he got to thinking about how it might be possible to recreate the technology. It was obvious that each bracelet would need to be very affordable, as they’re essentially party gifts. They also needed a way to communicate with each other and that is exactly the kind of situation in which mesh networking shines.

In a situation like this, one might consider transmitting a signal to all of the bracelets simultaneously in order to keep them in sync. But in the case of the Glastonbury Festival, that would require a massive and very powerful transmitter to cover the whole area. That is expensive and tends to drawn the scorn of government agencies. Thankfully, mesh networking is a perfect alternative. Each bracelet communicates with other bracelets nearby, so commands can be dispersed throughout the crowd. Because concerts are full of people spread out without much distance between them, mesh networking can cover the whole area.

To put that idea into practice, Nicholls designed some LED bracelets. Each has a Wemos D1 Mini ESP8266 development board, a strip of 12 WS2812B RGB LEDs, and a small 400mAh lithium battery. Those components fit inside a bracelet 3D-printed in flexible transparent TPU filament.

As programmed, the bracelets display a simple animation effect where they cycle through colors. The mesh networking comes into play by keeping the bracelets in sync. Turn one on and it will connect to its neighbors and start playing the same animation.

Nicholls tested this by making five bracelets. But, in theory, you could make as many as you wanted and as long as they formed an unbroken chain, they’d all stay synced together.