FastLED_RGBW for low dimming values

Simple_FastLED_RGBW_dimming.ino

/*

FastLED_RGBW attempt for low dimming values
 * Original code by Jim Bumgardner (http://krazydad.com).
 * Modified by David Madison (http://partsnotincluded.com).

https://github.com/FastLED/FastLED/wiki/FastLED-Temporal-Dithering
https://www.reddit.com/r/FastLED/comments/dp43fg/dim_led_below_1256_levels/

*/

#include "FastLED.h"
#include "FastLED_RGBW.h"

// number of LEDs on the strip
#define NUMPIXELS 240

const int bPin = A4;
const int DATA_PIN = 21;

int b;

CRGBW leds[NUMPIXELS];
CRGB *ledsRGB = (CRGB *) &leds[0];

void setup() {
  
  FastLED.addLeds<WS2812B, DATA_PIN, RGB>(ledsRGB, getRGBWsize(NUMPIXELS));

}

void loop() {

  // read from the sensor:
  b = map(analogRead(bPin), 0, 4095, 0, 255);

  for (int i = 0; i < NUMPIXELS; i++) {
    leds[i] = CRGBW(0, 0, b, 0);
  }

  // I also dim the whole strip by the same value
  // to achieve dithering less than 1/256 brightness
  FastLED.setBrightness(b);

  FastLED.show();
  FastLED.delay(1);        
}