#include <Adafruit_NeoPixel.h>

#define PIN 2
#define NUMPIXELS 12
Adafruit_NeoPixel pixels(NUMPIXELS, PIN, NEO_GRB + NEO_KHZ800);

#define DELAYVAL 20

void setup() {
  pixels.begin();
  SerialUSB.begin(115200);
}

void circle() {
  pixels.clear();
  for(int i = 0; i < NUMPIXELS; i++) {
    pixels.setPixelColor(i, pixels.Color(0, 50, 0));
    pixels.show();
    delay(DELAYVAL);
  }
  for(int i = 0; i < NUMPIXELS; i++) {
    pixels.setPixelColor(i, pixels.Color(0, 0, 0));
    pixels.show();
    delay(DELAYVAL);
  }
}

void loop() {
  if (SerialUSB.available()) {
    char c = SerialUSB.read();
    if (c == 'g') {
      // go!
      circle();
    }
  }
}