Lights up NeoPixel LED strip when it gets data from the Raspberry Pi via I2C

webofthingsi2c.ino

#include <Wire.h>
#include <Adafruit_NeoPixel.h>
#include <math.h>

#define PIN_A 6               //Strip #1
#define PIN_B 9               //Strip #2
#define PIN_LED 8            //Onboard LED

#define SLAVE_ADDRESS 0x04  //I2C address

Adafruit_NeoPixel onboard = Adafruit_NeoPixel(1, PIN_LED, NEO_GRB + NEO_KHZ800);
Adafruit_NeoPixel strip_one = Adafruit_NeoPixel(10, PIN_A, NEO_GRB + NEO_KHZ800);
Adafruit_NeoPixel strip_two = Adafruit_NeoPixel(5, PIN_B, NEO_GRB + NEO_KHZ800);

Adafruit_NeoPixel strips[2] = {
  strip_one,
  strip_two
};

int number = 0;
int state = 0;

void setup() {
  // put your setup code here, to run once:
  onboard.begin();
  onboard.show();
  strip_one.begin();
  strip_one.show();
  //Begin transmission of data between Pi and FLORA
  Wire.begin(SLAVE_ADDRESS);

  Wire.onReceive(receiveData);
  Wire.onRequest(sendData);
}

void loop() {}

void receiveData(int byteCount) {
  while(Wire.available()) {
    strip_one.show();
    //Get the number of wireless devices in the area
    //Divide by 2 since we only have half of our LEDs working
    number = floor(Wire.read() / 2);
    //Print for debug
    Serial.print("LEDS to light: ");
    Serial.println(number);
    int even = 0;
    int odd = 9;
    //TODO: Make it so that LEDs start displaying from bottom to top per strip
    for(int i = 0; i < number; i++) {
      int depth;
      if(i % 2 != 0) {
        depth = odd--;
      }
      else {
        depth = even++; 
      }
      Serial.print("LED #: ");
      Serial.println(depth);
      //Display white for now
      strip_one.setPixelColor(depth, strip_one.Color(255, 255, 255));
      strip_one.show();
      delay(50);
    }
    
    //Clear pixels that did not get lit up this iteration
    for(int j = even; j < 5; j++) {
      strip_one.setPixelColor(j, strip_one.Color(0, 0, 0, 0));
      strip_one.show();
    }

    for(int j = odd; j >= 5; j--) {
      strip_one.setPixelColor(j, strip_one.Color(0, 0, 0, 0));
      strip_one.show();
    }
  }
}

void sendData() {
  Wire.write(number);
}

// Fill the dots one after the other with a color
void colorWipe(uint32_t c, uint8_t wait) {
  for(uint16_t i=0; i<onboard.numPixels(); i++) {
      onboard.setPixelColor(i, c);
      onboard.show();
      delay(wait);
  }
}