neopixel-tail.ino

#include <Adafruit_NeoPixel.h>

#define PIN 6

Adafruit_NeoPixel strip = Adafruit_NeoPixel(200, PIN, NEO_GRB + NEO_KHZ800);

uint16_t pos = 0;
int tail = 20;

void setup() {
  strip.begin();
  strip.show();
}

void loop() {
  
  // turn off leds
  
  for(uint16_t i=0; i<strip.numPixels(); i++){
    strip.setPixelColor(i, 0,0,0);
  }
  
  // turn on only tail
  
  for(uint16_t i=0; i<tail; i++){
    int j = (pos + i) % strip.numPixels();
    strip.setPixelColor(j, 0,255,0);
  }
  
  strip.show();
  delay(10);
  
  pos = (pos + 1) % strip.numPixels();
}