NeoPixel

Presentation slides =

Class slides here:

Bill of Materials

Adafruit Metro Mini: https://www.adafruit.com/product/2590
NeoPixel Strip (60 LEDs per meter): https://www.adafruit.com/products/2842

Install the Arduino IDE

Grab the appropriate Arduino software from their website: https://www.arduino.cc/en/Main/Software
Follow the installation instructions for your operating system: https://www.arduino.cc/en/Guide/HomePage

Product link to Metro Mini

Technical details on the Metro Mini microcontroller from Adafruit: https://www.adafruit.com/product/2590

FastLED.io Documentation

Available on github: https://github.com/FastLED/FastLED/wiki/Overview
Color specific information: https://github.com/FastLED/FastLED/wiki/Pixel-reference#setting-rgb-colors

Class demo source code

Below, you will find the demo source code for the Hive76 NeoPixel class. Copy and paste this into the Arduino IDE to get started!

#include "FastLED.h"    // Loads FastLED library

#define NUM_LEDS 20     // How many NeoPixels on your strip? 
#define DATA_PIN 3      // Data pin from microcontroller connected to LED strip
#define BUTTON_PIN 4    // Data pin to read button state 
#define BUTTON_GND 6    // Data pin providing ground source to button, since we have limited mounting options for the Metro-Mini
#define KNOB_PIN A0     // analog input pin that is connected to the center pin of potentiometer, where pot position will be measured
#define KNOB_GND A1     // analog input pin that is connected to one side of potentiometer, and will be needed to supply ground

int buttonPressed = 1;  // initial state of push button, since input is pulled high and we need to declare variable scope. 

CRGB leds[NUM_LEDS];    // Tells the Library how many pixels we have

void setup() {
  // put your setup code here, to run once:
  FastLED.addLeds<NEOPIXEL,DATA_PIN>(leds, NUM_LEDS); // this specifies the configuration for the FastLED library
  pinMode(KNOB_GND, OUTPUT);                          // configures Analog pin to be an output...
  digitalWrite(KNOB_GND, LOW);                        // ...and writes a zero/low, to supply ground to the potentiometer
  pinMode(BUTTON_PIN, INPUT_PULLUP);                  // configures the digital pin for the button to be an input, and enable the internal pullup resistor
  pinMode(BUTTON_GND, OUTPUT);                        // configures the digital pin for the button ground to be an output...
  digitalWrite(BUTTON_GND, LOW);                      // ...and writes a zero/low, to supply ground to the button
}

void loop() {
  // put your main code here, to run repeatedly:
  int val = analogRead(KNOB_PIN);                 // reads the analog voltage of the potentiometer
  int colorOfLed = map(val, 0, 1023, 0, 255);     // this map function takes the 10-bit value read from potentiometer and converts to 8-bit value that can be used for the hue

  leds[0].setHSV( colorOfLed, 255, 200);          // sets the first NeoPixel to the hue of the potentiometer, with full color saturation and 200 brightness
  FastLED.show();                                 // sends the above data to the NeoPixels

  buttonPressed = digitalRead(BUTTON_PIN);        // read and store button state
  if (buttonPressed == LOW) {                     // logic check if button is currently pressed
    for (int i = 1; i < NUM_LEDS; i++) {          // this for loop starts at second pixel (1), then increments pixels until until it reachs the last LED on the strip
      leds[i] = CHSV( colorOfLed, 255, 200);      // sets the incremented pixel to the hue set by pot, full color saturation, 200 brightness
      FastLED.show();                             // writes data to the NeoPixels
      leds[i-1] = CRGB::Black;                    // blanks out the previous pixel
      FastLED.show();                             // writes data to the NeoPixels
      FastLED.delay(15);                          // delays 15ms between movement of each pixel
    }
    FastLED.clear();                              // turns off the pixels, and writes immediately, when the pixel animation loop above completes
  }
}