#include <Adafruit_NeoPixel.h>
int neopixel=9;
int no_led=20;
Adafruit_NeoPixel ring=Adafruit_NeoPixel(no_led, neopixel);
int LDR=A0;
int value=0;

void setup() {
  // put your setup code here, to run once:
  ring.begin();
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  value=analogRead(LDR);
  Serial.println(value);
  if (value > 1000)
  {
    Serial.println("Red");
    set_colour(ring.Color(255, 0, 0));
  }
  else if (value > 500)
  {
    Serial.println("Yellow");
    set_colour(ring.Color(255, 255, 0));
  }
  else
  {
    Serial.println("Green");
    set_colour(ring.Color(0, 255, 0));
  }
}

int set_colour(uint32_t col)
{
  for(int i=0; i<no_led; i++)
  {
      ring.setPixelColor(i, col);
      ring.show();
      delay(100);
  }
}