#include <FastLED_NeoPixel.h>
#define MAX_P 30
#define BUTTON_PIN 8
CRGB leds[MAX_P];

Adafruit_NeoPixel strip = Adafruit_NeoPixel(MAX_P, 3, NEO_BRG + NEO_KHZ800);

int potPin0 = 0;    
int potPin1 = 1;    
int val0 = 0;       
int val1 = 0;       
int li = 0;
int direction = 1;
uint32_t Red = strip.Color(255, 0, 0);
uint32_t Blank = strip.Color(0, 0, 0);
unsigned long buttonPressTime = 0;

void setup() {


  pinMode(8, OUTPUT);

  strip.begin();
  strip.show(); 
  
}

void loop() {

  digitalWrite (8, LOW);

// digitalWrite(8, HIGH); // Here the trigger is pulled high permanently 

  if (millis() - buttonPressTime >= 1000 && millis() - buttonPressTime <= 1000) {

  digitalWrite(8, HIGH); // not working ?

  }
  val0 = analogRead(potPin0) / 50;    // for 100k pot speed
  val1 = analogRead(potPin1) / 34.1;    // for 100k pot tail

  //decay
  for(uint16_t i=0; i<MAX_P; i++) {
    uint8_t r= (strip.getPixelColor(i)>>16) & 0xff;
    r=(r*(69+val1))/100;
      strip.setPixelColor(i, r, 0, 0);
  }

  strip.setPixelColor(li, Red);
  if(li>(MAX_P-1)){
    li=MAX_P;
    direction=-1;
  }else if(li<0){
    li=-1;
    direction=1;
  }
  li+=direction;
  strip.show();
  delay(val0);
  buttonPressTime = millis(); // Record the time for the button press

}