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 tutorial.
If the library is correctly installed (and the Arduino IDE is restarted), you should be able to navigate through the “File” rollover menus as follows:
File→Sketchbook→Libraries→Adafruit_NeoPixel→strandtest
Connect up your NeoPixels in a solderless breadboard and use alligator clips to attach to GEMMA, referring to the circuit diagram if necessary.
You’ll need to change a few lines in the code regarding the data pin (1), type of pixels (RGB vs GRB), and number of pixels (5). The resulting (and slightly simplified) code is below:
// SPDX-FileCopyrightText: 2017 Mikey Sklar for Adafruit Industries
//
// SPDX-License-Identifier: MIT
#include <Adafruit_NeoPixel.h>
#define PIN 1
// Parameter 1 = number of pixels in strip
// Parameter 2 = pin number (most are valid)
// Parameter 3 = pixel type flags, add together as needed:
// NEO_KHZ800 800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
// NEO_KHZ400 400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
// NEO_GRB Pixels are wired for GRB bitstream (most NeoPixel products)
// NEO_RGB Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
Adafruit_NeoPixel strip = Adafruit_NeoPixel(16, PIN, NEO_GRB + NEO_KHZ800);
// Here is where you can put in your favorite colors that will appear!
// just add new {nnn, nnn, nnn}, lines. They will be picked out randomly
// R G B
uint8_t myColors[][3] = {{232, 100, 255}, // purple
{200, 200, 20}, // yellow
{30, 200, 200}, // blue
};
// don't edit the line below
#define FAVCOLORS sizeof(myColors) / 3
void setup() {
strip.begin();
strip.setBrightness(40);
strip.show(); // Initialize all pixels to 'off'
}
void loop() {
flashRandom(5, 8); // first number is 'wait' delay, shorter num == shorter twinkle
flashRandom(5, 5); // second number is how many neopixels to simultaneously light up
flashRandom(5, 11);
colorWipe(strip.Color(232, 100, 255), 50); // Red
colorWipe(strip.Color(200, 200, 20), 50); // Green
colorWipe(strip.Color(30, 200, 200), 50); // Blue
rainbowCycle(20);
}
// Fill the dots one after the other with a color
void colorWipe(uint32_t c, uint8_t wait) {
for(uint16_t i=0; i<strip.numPixels(); i++) {
strip.setPixelColor(i, c);
strip.show();
delay(wait);
}
}
void rainbow(uint8_t wait) {
uint16_t i, j;
for(j=0; j<256; j++) {
for(i=0; i<strip.numPixels(); i++) {
strip.setPixelColor(i, Wheel((i+j) & 255));
}
strip.show();
delay(wait);
}
}
// Slightly different, this makes the rainbow equally distributed throughout
void rainbowCycle(uint8_t wait) {
uint16_t i, j;
for(j=0; j<256*5; j++) { // 5 cycles of all colors on wheel
for(i=0; i< strip.numPixels(); i++) {
strip.setPixelColor(i, Wheel(((i * 256 / strip.numPixels()) + j) & 255));
}
strip.show();
delay(wait);
}
}
// Input a value 0 to 255 to get a color value.
// The colours are a transition r - g - b - back to r.
uint32_t Wheel(byte WheelPos) {
if(WheelPos < 85) {
return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
} else if(WheelPos < 170) {
WheelPos -= 85;
return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
} else {
WheelPos -= 170;
return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
}
}
void flashRandom(int wait, uint8_t howmany) {
for(uint16_t i=0; i<howmany; i++) {
// pick a random favorite color!
int c = random(FAVCOLORS);
int red = myColors[c][0];
int green = myColors[c][1];
int blue = myColors[c][2];
// get a random pixel from the list
int j = random(strip.numPixels());
// now we will 'fade' it in 5 steps
for (int x=0; x < 5; x++) {
int r = red * (x+1); r /= 5;
int g = green * (x+1); g /= 5;
int b = blue * (x+1); b /= 5;
strip.setPixelColor(j, strip.Color(r, g, b));
strip.show();
delay(wait);
}
// & fade out in 5 steps
for (int x=5; x >= 0; x--) {
int r = red * x; r /= 5;
int g = green * x; g /= 5;
int b = blue * x; b /= 5;
strip.setPixelColor(j, strip.Color(r, g, b));
strip.show();
delay(wait);
}
}
// LEDs will be off when done (they are faded to 0)
}
From the Tools→Board menu, select the device you are using:
- Adafruit Gemma M0
- Adafruit Gemma 8 MHz
Connect the USB cable between the computer and your device. The original Gemma (8 MHz) need the reset button pressed on the board, then click the upload button (right arrow icon) in the Arduino IDE. You do not need to press the reset on the newer Gemma M0.
When the battery is connected, you should get a light show from the LEDs. All your pixels working? Great! You can take apart this prototype and get ready to put the pixels in the collar. Refer to the NeoPixel Uberguide for more info.
