Programmable LEDs

LED strip

• RS product: https://se.rs-online.com/web/p/led-ljuslister/1807500?gb=s
  • Datasheet: https://docs.rs-online.com/c4c2/0900766b816d3d12.pdf

Dependencies

• Install the library FastLED: https://github.com/FastLED/FastLED
  • Documentation: https://github.com/FastLED/FastLED/wiki/Overview
  • Basic usage: https://github.com/FastLED/FastLED/wiki/Basic-usage

Examples online

• https://learn.adafruit.com/adafruit-neopixel-uberguide/the-magic-of-neopixels
• https://create.arduino.cc/projecthub/whimsy-makerspace/arduino-compatible-nano-neopixel-controller-6f0c4b

How to use

Install the FastLED library in the Arduino IDE.

How to connect the LED strip

Make sure the arrows are pointing to the right direction. The beginning of an arrow indicates the connection point to the Arduino board. The tip of the arrow show how the current flows in the strip.

Source code

Important functions:

• random()
• randomSeed()
• addLeds()
• setBrightness()

The script depends on the number of LEDs (see variable NUM_LEDS).

// include library
#include<FastLED.h>

//define number of LED and pin
#define NUM_LEDS 4
#define DATA_PIN 3

// create the ld object array
CRGB leds[NUM_LEDS];

// define 3 byte for the random color
byte  r, g, b;
float brightness;

void setup() {
  Serial.begin(9600);
  // init the LED object
  FastLED.addLeds<NEOPIXEL, DATA_PIN>(leds, NUM_LEDS);
  // set random seed
  randomSeed(analogRead(0));
}

void loop() {
  // loop over the NUM_LEDS
  for (int cur = 0; cur < NUM_LEDS; cur++) {
    brightness = 50.0 / pow(2, cur);
    FastLED.setBrightness(brightness); // range: 0-255
    r = random(150, 200);
    g = random(100, 150);
    b = random(0, 50);
    //set the value to the led AND turn on
    leds[cur] = CRGB(r, g, b); FastLED.show();
    FastLED.delay(200);
    // turn off previous
    leds[cur] = CRGB::Black; FastLED.show();
    Serial.println(cur, DEC);
  }
}