2221 - ADAFRUIT - Datasheet.Live

Kaleidoscope Eyes (Trinket-Powered NeoPixel LED Ring

Goggles)

Created by Phillip Burgess

Last updated on 2019-04-09 06:03:16 PM UTC

Overview

Here’s a project to dazzle onlookers at Halloween parties, cosplay conventions, raves or at Burning Man. These full-

color animated LED goggles attract a LOT of attention!

Adafruit NeoPixel LED rings fit perfectly inside the eyecups of most 50mm round goggles — a very common size. It’s

almost as if these rings were

made

with this project in mind!

Tools Needed

This guide was written for the Trinket Mini boards, but can be done with either the Trinket Mini or Trinket M0.

We recommend the Trinket M0 as it is easier to use and is more compatible with modern computers!

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This is a soldering project, albeit a small one. You will need the common soldering paraphernalia of a soldering iron,

solder and tools for cutting and stripping wire.

You’ll need some method of securing the electronics inside the goggles. Hot-melt glue (with a glue gun) works well for

this. Watch your fingers! Or craft glue (such as E6000) is an Adafruit favorite. Tape could be used for a quick and

temporary setup.

Parts Needed

We have a DIY kit with all the necessary pieces (including goggles), or you can “bring your own goggles” for a custom-

made design.

The kit version includes our costume

goggles (https://adafru.it/e1O), two NeoPixel

rings (https://adafru.it/dyU), a Trinket

M0 (https://adafru.it/Agg) or Trinket Mini

Microcontroller (https://adafru.it/dyV), JST

connector (http://adafru.it/1769), rechargeable 150 mAh

LiPoly battery (https://adafru.it/dYY), enough wire for all

the connections, plus a USB battery

charger (https://adafru.it/doR).

…or Bring-Your-Own-Goggles

If you already have a favorite pair of goggles that you’d rather build this around (these German

goggles (https://adafru.it/cFm) from Restoration Hardware are pretty cool), then you just need to add the electronic

parts linked above. You also then have the option of stepping up to a larger 500 mAh LiPoly

battery (https://adafru.it/drL) or a less costly 3x AAA battery case (https://adafru.it/dYF). You’ll need to provide your

own wire and perhaps some heat-shrink tubing.

An assortment of goggles…the ones in front are safety

and welding goggles, while the two in back are costume

shop and toy store finds. Yet they all use 50mm round

lenses!

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

If you go the custom route, the design must be adapted to fit your reality.

Great thing about our costume goggles (https://adafru.it/e1O) is that you can assemble all the electronics first,

outside

the goggles,

then

install them. That’s not always the case with these alternates…you may need to snake wires in and

out of the eye cups and solder parts with them already in the goggles…this can be tricky! Soldering novices may

prefer the kit version for this reason.

If you choose a 3x AAA battery case (instead of a rechargeable LiPoly battery), it won’t fit inside the goggles. This

could be attached to the strap, or run longer wires and keep the battery pack in a pocket.

Can I use a Gemma instead of a Trinket?

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Wiring & Soldering

Before starting, take inventory of all your parts:

Goggles

NeoPixel rings (2)

Trinket M0 or Trinket Mini Microcontroller

JST connector

Micro LiPo USB charger

LiPoly battery

Wire

Your kit might have a couple of extra bits; a small power

cable and some pin headers. If present, they can be

tossed in your spare parts drawer; they’re not used

here.

If this is your first time using the Adafruit Trinket microcontroller, work through the Adafruit Trinket

M0 (https://adafru.it/Agg) or Introducing Trinket (https://adafru.it/dhx) guide first. This explains how to set up the

Arduino IDE software and load code onto the board. Don’t continue here until you have something like the “pulse”

example working.

If you encounter problems, post on the Adafruit Forums (https://adafru.it/cer) for help…it’s

much

easier to troubleshoot

and replace parts before they’re soldered together and glued into some goggles!

Let’s get the trickiest soldering out of the way first, installing the JST battery connector on the underside side of the

Trinket board…

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Start by “tinning” one of the JST pads on the back of the

Trinket…heat the pad and apply solder so the whole

surface is covered.

Hold the JST socket in place (tweezers recommended)

and re-melt the solder, allowing the part to sink into

position.

Once this first pin is tacked down, the rest are easy.

Remember to

heat the parts, then apply solder

…do not

melt solder on the iron and “wipe” it on the parts…that

makes a weak

cold solder joint.

Properly done, the

connections should be shiny and smooth.

Congrats, you’ve done surface-mount soldering!

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Next, peel away

two sets

of

three wires each

from the

included bit of ribbon cable. (If you’re building your own

custom goggles, you can just use separate pieces of

wire for this, it’s all good.)

If using our costume goggles, one of these 3-wire cables

will be visible on the outside, so pick a color

combination that you like.

Separate the wires by about 1 inch at both ends, strip

away a little insulation and give the wires a twist to

prevent fraying. Optionally

tinning

the wire ends makes

them a little more manageable…heat each one with a

soldering iron and melt just a tiny bit of solder into the

strands.

If you mess this part up, that’s okay. Trim the wires back

a little further and try again. Or use the left-over wire

from the original ribbon cable.

Here’s a circuit diagram of what we’re aiming for. Of course the real thing won’t be all rectilinear like this…we’ll walk

you through each step.

This diagram uses the original Trinket but you can also use the Trinket M0 with the exact same wiring!

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Solder one end of the 3-wire cables to the IN, V+ and G points on the two NeoPixel rings. There are

two

V+ and

two

G

holes on each ring…either one is fine, they’re connected.

Keep track of the colors you use for IN, V+ and G…it’s vitally important to make the right connections at the other end.

(These are the labels on the

front

of the rings. The back-side labels are a little more verbose.)

Notice how the wires are inserted from the front, then

soldered on the back

of the ring. Do it this way if you’re new to

soldering…it’s much easier. It

can

work the other way too…insert from back, solder on front…but the component

tolerances are

extremely

tight and beginners often get a blob of solder in the wrong place and the LEDs don’t work.

Next we connect the other ends of the 3-wire cables…first one to the Trinket, second one joins the two rings…

The second cable is the “visible from the outside” one, if that matters to your color scheme.

Notice here how the second cable enters the first ring from behind, then the wires are inserted from the front and

soldered on the back…the cables should

not

overlap any LEDs on the front.

Trinket First Ring

BAT+ V+ (either one)

Gnd G (either one)

#0 IN

First Ring Second Ring

V+ (either one) V+ (either one)

G (either one) G (either one)

out IN

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If possible, try to align the rings so they’re pointed nearly the same direction (use a landmark like the Adafruit logo for

reference). This is not required, but it’s a little easier to program animation effects when both rings have the same

orientation.

If using the “bring your own goggles” method, things

may be a lot more complex…for example, these goggles

have wires passing in and out through side perforations,

so it’s not possible to build and test the whole circuit

separately first…it must be built around the goggles and

is later folded into place. This is tricky!

We’ll clip the wire ends flush in a moment, but let’s test that everything works first…

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Arduino Code

If you haven’t already worked through the Adafruit Trinket M0 (https://adafru.it/Agg) or Introducing

Trinket (https://adafru.it/cEu) guide, do that first. Once you have the Arduino IDE up and running, then download and

install the NeoPixel library:

https://adafru.it/cDj

Installing Arduino libraries is a frequent stumbling block. If this is your first time, or simply needing a refresher, please

read the All About Arduino Libraries (https://adafru.it/aYM) tutorial.

Create a new Arduino sketch (File→New), then copy and paste the following code:

The Arduino code presented below works equally well on all versions of Trinket Mini and Trinket M0. But if

you have an M0 board, consider using the CircuitPython code on the next page of this guide, no Arduino IDE

required!



// Low power NeoPixel goggles example. Makes a nice blinky display

// with just a few LEDs on at any time.

#include <Adafruit_NeoPixel.h>

#ifdef __AVR_ATtiny85__ // Trinket, Gemma, etc.

#include <avr/power.h>

#endif

#define PIN 0

Adafruit_NeoPixel pixels = Adafruit_NeoPixel(32, PIN);

uint8_t mode = 0, // Current animation effect

offset = 0; // Position of spinny eyes

uint32_t color = 0xFF0000; // Start red

uint32_t prevTime;

void setup() {

#ifdef __AVR_ATtiny85__ // Trinket, Gemma, etc.

if(F_CPU == 16000000) clock_prescale_set(clock_div_1);

#endif

pixels.begin();

pixels.setBrightness(85); // 1/3 brightness

prevTime = millis();

}

void loop() {

uint8_t i;

uint32_t t;

switch(mode) {

case 0: // Random sparks - just one LED on at a time!

i = random(32);

pixels.setPixelColor(i, color);

pixels.show();

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From the Tools→Board menu, select either Adafruit Trinket 8 MHz or Adafruit Trinket 16 MHz (either one will work).

Also make sure to select USBTinyISP from the Tools:Programmer menu. Connect the USB cable between the

computer and Trinket, press the reset button on the board, then click the upload button (right arrow icon) in the

Arduino IDE.

Nothing will happen at first, this is normal. The LEDs only work on battery power! Unplug the USB cable, then connect

the battery to the JST plug on the back of the Trinket. If all goes well, you should get a sparkly light show from the

LEDs.

Success! Unplug the battery and we’ll move on to the

final assembly…

(These rings are running a different sketch…more on that

in a bit.)

pixels.show();

delay(10);

pixels.setPixelColor(i, 0);

break;

case 1: // Spinny wheels (8 LEDs on at a time)

for(i=0; i<16; i++) {

uint32_t c = 0;

if(((offset + i) & 7) < 2) c = color; // 4 pixels on...

pixels.setPixelColor( i, c); // First eye

pixels.setPixelColor(31-i, c); // Second eye (flipped)

}

pixels.show();

offset++;

delay(50);

break;

}

t = millis();

if((t - prevTime) > 8000) { // Every 8 seconds...

mode++; // Next mode

if(mode > 1) { // End of modes?

mode = 0; // Start modes over

color >>= 8; // Next color R->G->B

if(!color) color = 0xFF0000; // Reset to red

}

for(i=0; i<32; i++) pixels.setPixelColor(i, 0);

prevTime = t;

}

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If the code refuses to compile it’s usually one of the following:

The Trinket extensions to the Arduino IDE are not correctly installed (use the ready-made IDE, it’s easier).

The NeoPixel library is not correctly installed.

The wrong board type is selected (should be Adafruit Trinket M0, Adafruit Trinket 8 MHz or 16 MHz,

not

any

version of the Pro Trinket).

If the code compiles and uploads but nothing happens with the battery connected:

Compare your connections against the wiring diagram…for example, maybe you’ve accidentally connected

Trinket pin #0 to the first ring’s OUT instead of IN?

An electrical short…a blob of solder or bit of wire making inadvertent contact with something nearby.

A cold solder joint…solder isn’t properly melted between the wire and board.

If you can’t identify the source of the problem, you can post in the Adafruit Forums (https://adafru.it/cer) for assistance.

It’s very helpful if you can get a well-lit, in-focus photo (or several) of the project, showing all the wires and solder

connections. We’ll look it over for any gremlins and recommend fixes.

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CircuitPython Code

Program the Trinket M0 w/ CircuitPython

Trinket M0 Setup for CircuitPython

Now it's time to set up the Trinket M0 for use with CircuitPython (https://adafru.it/zB0) and our Screaming

Cauldron code.

If you haven't already, follow this guide (https://adafru.it/ABS) to preparing the Trinket M0, including updating it with

the latest version of CircuitPython.

After prepping the Trinket M0 to run CircuitPython we'll also need to add a NeoPixel library. This guide tells you

how (https://adafru.it/Euo), as well as providing a good primer on using NeoPixels on the Trinket

M0 with CircuitPython.

Installing NeoPixel Library

Download the latest adafruit-circuitpython-bundle-xxxx.zip (or newer) from the releases directory (https://adafru.it/zB-

)and then unzip it somewhere easy to find, such as your desktop. Then, copy the neopixel.mpy file to your

CIRCUITPY's lib directory on the Trinket M0.

Finally, if you had a neopixel.py file that was already in that same lib directory you can delete it (the mpy is a

compressed version)

Saving CircuitPython Code

Once you've got things working, you can edit the main.py file on the Trinket M0 to adjust what it actually does. No

need for a software IDE, complaining tools, or flashing the chip -- when you code with CircuitPython all you need is a

text editor. Edit the code, save it to the Trinket M0, and it immediately runs!

#

# Kaleidoscope_Eyes_NeoPixel_LED_Goggles.py

#

import time

import board

import neopixel

try:

import urandom as random # for v1.0 API support

except ImportError:

import random

numpix = 32 # Number of NeoPixels

pixpin = board.D0 # Pin where NeoPixels are connected

mode = 0 # Current animation effect

offset = 0 # Position of spinny eyes

rgb_colors = ([255, 0, 0], # red

[0, 255, 0], # green

[0, 0, 255]) # blue

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Copy that code, and then paste it into a new text document in your favorite text/coding editor. Then, save it to your

Trinket M0's CIRCUITPY drive as main.py

[0, 0, 255]) # blue

rgb_idx = 0 # index counter - primary color we are on

color = rgb_colors[rgb_idx]

prevtime = 0

pixels = neopixel.NeoPixel(pixpin, numpix, brightness=.3, auto_write=False)

prevtime = time.monotonic()

while True:

i = 0

t = 0

# Random sparks - just one LED on at a time!

if mode == 0:

i = random.randint(0, (numpix - 1))

pixels[i] = color

pixels.write()

time.sleep(0.01)

pixels[i] = (0, 0, 0)

# Spinny wheels (8 LEDs on at a time)

elif mode == 1:

for i in range(0, numpix):

c = 0

# 4 pixels on...

if ((offset + i) & 7) < 2:

c = color

pixels[i] = c # First eye

pixels[(numpix - 1) - i] = c # Second eye (flipped)

pixels.write()

offset += 1

time.sleep(0.05)

t = time.monotonic()

if (t - prevtime) > 8: # Every 8 seconds...

mode += 1 # Next mode

if mode > 1: # End of modes?

mode = 0 # Start modes over

if rgb_idx > 2: # reset R-->G-->B rotation

rgb_idx = 0

color = rgb_colors[rgb_idx] # next color assignment

rgb_idx += 1

for i in range(0, numpix):

pixels[i] = (0, 0, 0)

prevtime = t

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Final Assembly and Use

With the electronics squared away, let’s move on to the arts & crafts part of the project!

First, if you haven’t already, clip off the tips of the

soldered wires.

Gather these up and throw them away…make sure the

clipped bits don’t end up inside the goggles where

they’d cause electrical shorts.

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This step is optional but recommended: if you have

some 5-minute epoxy or craft adhesive such as E6000,

add a small bead at the base of each wire where it

meets the board…and

especially

on the LiPoly battery

and JST connector. This creates a

strain relief,

so wires

aren’t likely to break off when flexed. On the NeoPixel

rings, it helps the wires sit flat.

Wait until the glue or epoxy is fully cured before final

assembly or charging the battery.

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Unscrew the rings holding the lenses in place. Most

goggles (whether our costume variety or the bring-your-

own type) will have a couple different layers inside,

some clear, some darkened. Set the dark lenses aside,

we’ll just be using the clear ones.

The costume goggles have slots near the nose piece,

bridged by a tiny bit of plastic. If these are clipped away,

then all the electronics can be slid in place from the

front. You might also cut the slots just a little wider so

they don’t gouge the wires.

Bring-your-own goggles usually aren’t built this way,

which is why assembly is more involved.

The NeoPixel LEDs are very bright and focused. Let’s make some diffusers to soften the light.

Trace one of the lenses on a piece of paper, then cut it out with scissors. Ordinary printer/copier paper works just fine,

or I had this fancy-pants vellum on-hand (it required two layers).

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If you have access to a laser cutter (through a local hackerspace, your school, whatever), measure the diameter of the

lenses for cutting new ones. 1/16" white acrylic works well for this.

Some of our early photos show ring-shaped diffusers, but we found the goggles were best used as a decorative

hatband and

not

worn (more on this later). So go ahead and make solid diffusers. It’s much easier and looks cool.

Insert the electronics into the goggles from the front,

with the ring-to-ring ribbon cable across the bridge of

the nose.

Prepare the lenses — clear layer first, then the diffuser,

then optionally the spacer ring from the original lenses.

Screw the lenses in place, being super extra careful not

to gouge the wires!

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Connect the battery briefly to make sure all the electronics are happy prior to final assembly. It’s easier to troubleshoot

while everything’s out in the open.

If using metal goggles, make sure there’s no contact between the goggles and any exposed conductors.

The rings are then secured in place with a few dabs of hot glue or fast-setting epoxy. Glue just a couple spots at a

time, so you can hold the rings centered while it sets.

Finally, the Trinket is then glued to the outer edge of the eye cup, with the USB port and battery connector both

accessible. (If using metal goggles, use tape or something to provide an insulating layer.) The wires can be folded and

held in place with additional dabs of glue.

PRO TIP:

if you used hot glue and need to remove the rings later, dip a Q-Tip in rubbing alcohol, touch it to the edge of

each blob of glue and allow it to soak in for a few seconds. This doesn’t

dissolve

the glue; it seeps between the two

parts and cleanly

breaks the bond.

The glue should peel away with little effort. Science!

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Power on the goggles by connecting the battery.

The battery is small enough to tuck away inside the eye

cup. Add a bit of masking tape to hold it in place if

needed.

SAFETY AND COMMON SENSE

Your LED goggles are a

fashion accessory

— they should be worn on your forehead or on a hat, not over your

eyes. Even if you block most of the light inside, even a small scattered bit is still very bright and will cause headaches,

maybe even vomiting (https://adafru.it/cFK). If you leave out the diffusers and try to see through the rings, peripheral

vision is severely limited. Wearing these goggles on one’s face is just not smart…stick them up above!

If you’ve modified a pair of welding or safety goggles, their design is now

compromised

and they should no longer be

used for welding or safety!

For the same reasons, if attending an event like Burning Man, take one (or several) pairs of “real” sealed dust goggles

in addition to your LED “fun” goggles. Don’t rely on the latter for protection.

Safety Checklist:

Never use the altered goggles for safety or eyewear; they’re strictly a fashion item.

If your goggles have metal frames, make sure there's no contact with exposed conductors on the Trinket board,

NeoPixel rings or wires.

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