Synchronized LED Accessory Set

Project Summary

This is the first version of my wireless LED accessory set. It features seven leather bands, each with 28 WS2812 RGB LEDs, an ESP32C3 XIAO board, and a 300mAh battery. The bands are all synchronized (technically) to a main remote which can select different patterns for the set as a whole to display. The effect is completely mesmerizing (especially in person) and prompted many, many future iterations on this idea.

In terms of parts, these bands are the least complicated of all future iterations – just leather, snaps, led strip, battery, and off-the-shelf microcontroller. In terms of construction, however, they were a huge headache.

Design

The body of the band is a single piece of ~3mm veg-tanned leather that has been lazer cut to make clean LED cut-outs. The microcontroller has had the battery soldered on and both are stored in a small 3D-printed shell that is held onto the leather with screws. The LED strips are attached to the band with quick-hold E6000. The band is secured onto my arms with snaps, and each band is one of three sizes, depending on where it sits on the arm.

The suiting up process (L) and the battery/MCU unit on wrist (R).

Each band uses 3 LED strips which were painstakingly wired to each other and to the microcontroller. 3 tiny wires times 3 connections times 7 bands equals 63 tiny wires and makes Jack a dull boy. These bands were very annoying to assemble and very prone to breaking due to all the tiny yet vital exposed wires. Thankfully, they survived the event that I made them for (but didn’t last much longer afterwards).

You may notice the lack of an on/off switch, and that’s a sacrifice I had to make with off-the-shelf components and extremely limited space. To turn them ‘off’, the best I could do was send a command wirelessly to put them into the esp32c3’s “deep sleep” mode, and then I could turn them back on by manually hitting the tiny reset button on each board. It was a lot less than ideal!

The Remote

To control the bands, I made a little remote for selecting different patterns and colors to broadcast to the bands. There are four parameters that can be motified by the remote: the HSV values for a specific color to be selected, and a pattern value saying how that color will be used (ex. in an arrow pattern, in a pulsing wave, or maybe not at all and the bands will do a rainbow design or gradient). A 4 way rotary switch selects which parameter is being edited, a rotary encoder modifies the parameter, a single LED shows the selected color, and the top has an on/off switch and a “send” button that updates the bands.

The remote has a belt clip on the back, but unfortunately neither me nor my date had a belt or anything that could hold the weight of the device, so removing the need for a bulky remote was added to the list of things to revise for future iterations.

Software

These bands are technically synchronized to each other, but in reality they function more like radio recievers with the remote functioning as a transmitter. The remote sends a single command with the user’s parameters to every band at once, and the bands recieve the message and interpret the parameters at the same time (or within a few ms). This makes them all appear to act at the same time, but they are actually just running hardcoded routines that have been uploaded to every band and just changing the parameters and resetting the start point of the routine every time a message is recieved. In future iterations, the relationships of the bands to an exterior unit, and to each other, become a lot more involved and consequently more responsive and interactive. But this approach was good enough for a v1!

The bands simultaneously recieve a command to increase brightness.

Aesthetics

What more is there to say? These came out so nice that I still haven’t stopped iterating on them. Something about the black leather and the nested LEDs, when they’re all pulsing or changing at the same time, is absolutely mesmerizing.