RGB LED earrings for festivals, parties, raves, hacker events, etc. Each earring weighs about 1.8g, or 2.8g including the battery. This is comparable to most earrings.

WARNING: these earrings come without a battery. See "What's in the box" below where you can buy them.

Patterns

These earrings can be run with various patterns! It has two buttons to cycle through them. The top one cycles through different modes (and can be long-pressed to turn it on/off), the bottom one cycles through various colors/patterns within a mode:

1. Rotating colors:
   1. Rotating colors, cycling through all rainbow colors with the two sides having opposite colors.
   2. Red and blue ("fire and ice") rotating in a similar fashion.
   3. Three pink rotating tracers.
2. Noise effect (Perlin noise), slowly swirling around:
   1. FastLED "PartyColors"
   2. FastLED "RainbowColors"
   3. FastLED "ForestColors"
   4. FastLED "OceanColors"
   5. FastLED "CloudColors"
3. Fire-like animation in various colors:
   1. Red
   2. Orange
   3. Green
   4. Teal
   5. Blue
   6. Purple
4. Audio reactive fire effect (same colors as before).
5. Static color, cycle through them with the 2nd button
6. Pride flags:
   1. Pride flag 🏳️‍🌈
   2. Trans flag 🏳️‍⚧️
   3. Lesbian flag
   4. Gay flag
   5. Non-binary flag
   6. Bi flag
   7. Pansexual flag
   8. Asexual flag (more or less, black can't be shown as a color)
   9. Aromantic flag (more or less, black can't be shown as a color)
   10. New polyamory flag
7. Sparkle animation with two colors, somewhat audio responsive
   1. purple/turquise
   2. purple/red
   3. red/yellow
   4. yellow/green
8. VU meter animation, responding audio in the surroundings (but note that it automatically calibrates so it doesn't actually show audio volume).
9. Custom pattern 1 (see below), initially just 1 blue LED.
10. Custom pattern 2, initially just 2 blue LEDs.
11. Custom pattern 3, initially just 3 blue LEDs.

How to use

Insert the battery with the flat side (with markings) to the outside. The rounded side goes to the inside, pressed to the PCB. Inserting them the wrong way around won't harm the earrings, but the battery might drain quickly so check the polarity. The earring should light up immediately after inserting the battery.

You can select the mode using the buttons on the back. For a list of modes, see above.

Afterwards, it's best to remove the batteries and put them in separate plastic bags (included with the earrings). You can use the included wooden stick to remove them by pushing from the top - they're really hard to remove otherwise!

The batteries will typically last for over 24 hours, depending on the mode, and the type and quality of the battery. So you can use them for multiple nights at a festival. The blue color will fade first when the batteries run out, this is how you can see the batteries run down.

Custom patterns

You can write your own custom patterns, and upload them to the earrings via sound! Initially these custom patterns are 1-3 blue LEDs but they will switch to a saved pattern after 1 second (if one has been uploaded).

Warning: this feature is EXPERIMENTAL. There may be bugs. Patterns run without sandbox, directly as machine code on the earring so be especially careful with code shared by others. A malicious pattern can brick the firmware. While I test each earring to check whether this feature works, I cannot at the moment guarantee that it will work (but please contact me if it doesn't).

Steps to make a custom pattern:

1. Design your own pattern in the LED editor. You can program something yourself, or use a pattern shared by someone else. At the moment, the FastLED platform has the best support. Make sure to keep it small, a custom pattern can only be 1.5kB in size!
2. Put the earring in programming mode, by first going to the custom pattern you want to replace (1-3 blue LEDs) and then long-pressing the "variant" button. The blue LEDs will turn faint purple.
3. Press the "scream" button in the web interface. Warning: this will produce a loud noise!
4. Hold the earrings close to the speaker (the small rectangular metal component on the front is the microphone, it should face the speaker). Watch the LEDs: purple means ready to receive, blinking means receiving data, and green means fully received and writing the pattern to flash.
5. Enjoy the new pattern! It should start running immediately. Small differences in color and speed of the animation are expected, but it should look very similar.

If transmission is interrupted, that's no problem. Just keep the microphone close enough that it will continue receiving data. Once enough blocks of data have been received, the binary can be recovered. This is thanks to a simple fountain code.

Not all speakers will produce clean enough sound for this to work. It appears that headphones (at high volume) and small Bluetooth speakers work best. Phone speakers may or may not work. Fancy speakers with multiple cones (separate bass/treble) and laptop speakers may not work at all. You'll have to experiment a bit to find out!

Other tips:

• Hold the earrings close to the speaker, and keep the distance constant.
• Avoid noise and vibration in the environment.
• Use a high volume, but don't make it overly loud.
• Make sure to use a fresh battery, it may not work well with a battery that's starting to run out of power. (Or: connect the VCC/GND pins to a 3.3V power source for an extra boost - make sure to remove the coin cell first!)

What's in the box

• A pair of earrings. You can choose from a few different earring hook types:
  • Silver, looks shiny and is tolerable for most people (though note that the battery holder is nickel plated if you're very sensitive)
  • Titanium, this will look a bit more dull than silver but is extremely hypoallergic
  • Gold colored, according to the seller of these hooks this is gold plated brass
  • Clip on, you can use these even if your ears aren't pierced but some people might find them uncomfortable.
• A protective case, to store the earrings.
• Some documentation on paper.
• Two small plastic bags to store the batteries safely.
• A small wooden stick to easily push out the batteries for storage.

Unfortunately, batteries are not included since shipping these batteries comes with various restrictions. Luckily, they're easy to find online on your local Amazon/eBay/Bol/etc under the name CR1225 (usually in a pack of 5 for a few euros). They're hard to find (and expensive!) in physical stores, so I recommend buying them online. There's also another type that you can use (CR1220) but be careful since these might fall out more easily.

How they are built

These earrings use an STM32L031 microcontroller to control the 36 RGB LEDs with Charlieplexing. By using Charlieplexing, it is possible to control all 36 RGB LEDs with just 12 GPIO pins - many more pins would have been needed with traditional multiplexing.

The PCBs are made and assembled by JLCPCB. I program them, depanel them, test them, and attach earring hooks to them so they are ready to use. Since it's all open source, you can do this yourself if you want.

Open Source

These earrings are open source! The design files and the code is on GitHub, see the code link below.

The firmware on the earrings is written in the Go programming language (yes, really) using TinyGo. Controlling the LEDs is done directly in assembly due to the tight timings, but the animations are all done in Go. See the documentation link below for the source code. So if you feel like it, you can even program your own LED animations! Of course, they come pre-programmed so you don't need to do anything special.

I got inspiration from the really cool earrings made by California STEAM, also here on Lectronz. Check them out!

It may take a few days for me to send the package.

All packages are sent via normal mail and will fit in a standard letterbox. You don't need to be home to receive the package. If you want other options (or no shipping option is available), please message me.

Import fees:

EU: none (VAT exempt in most EU countries)

UK: none expected below £135

US: none (tariffs collected at checkout, no one seems to know the actual tariffs but since this is DDP you don't need to pay for it)

Rest of world: buyer's responsibility. Usually there's an exception for low value goods but check with your customs to be sure.