sinelon_subpixel.ino

/* Poor man's 1D subpixel rendering.

   By: Andrew Tuline

   Date: Oct, 2021

  Supports partial brightness both before and after the 'current' led.

*/

#include <FastLED.h>

#define LED_DT 12
#define NUM_LEDS 60

struct CRGB leds[NUM_LEDS];

void setup() {
  Serial.begin(115200);
  LEDS.addLeds<WS2812, LED_DT, GRB>(leds, NUM_LEDS);
} // setup()


void loop () {

  float t = (sin((float)millis() / 1000.) + 1.0) / 2.;            // Make a slow sine wave and convert output range from -1.0 and 1.0 to between 0 and 1.0.
  t = t * (float)NUM_LEDS;                                        // Now map to the length of the strand.

  for (int i = 0; i < NUM_LEDS; i++)
  {
    float diff = abs(t - (float)i);                               // Get difference between t and current location. Greater distance = lower brightness.
    if (diff > 2.0) diff = 2.0;                                   // Let's not overflow.
    float bri = 256 - diff * 128;                                 // Scale the brightness to up to 255. Closer = brighter.
    leds[i] = CHSV(0, 255, (uint8_t)bri);
  }

  FastLED.show();
} // loop()