// Simulates a 6 digit Nixie Clock.
// The Nixie tube and driver (K155ID1 or 74141) are
// simulated by a custom chip and 7 segment display.

#define DATA_PIN  8   // Pin connected to DS of 74HC595
#define LATCH_PIN 9   // Pin connected to STCP of 74HC595
#define CLOCK_PIN 10  // Pin connected to SHCP of 74HC595
#define LED_PIN 7     // Led Data Pin
#define NUM_LEDS 6    // The number of leds

byte data[3] = { 0, 0, 0}; // hh, mm, ss
byte nixie[6] = { 0, 0, 0, 0, 0, 0};
int counter = 0;

void setup() {
  pinMode(DATA_PIN, OUTPUT);
  pinMode(CLOCK_PIN, OUTPUT);
  pinMode(LATCH_PIN, OUTPUT);

  Serial.begin(115200);

  randomSeed(analogRead(0));
}

void loop() {

  for(int i=0; i<6; i++)
  {
    float f = (float)i / 6.0;
    nixie[i] = sin(f * PI) * 9;
  }

  // nixie[0] = 1;
  // nixie[1] = 2;
  // nixie[2] = 3;
  // nixie[3] = 4;
  // nixie[4] = 5;
  // nixie[5] = 6;

  outputNixies();

  counter++;
  delay(200);
}

void outputNixies() {
  data[0] = setByte(nixie[0], nixie[1]);
  data[1] = setByte(nixie[2], nixie[3]);
  data[2] = setByte(nixie[4], nixie[5]);
  shiftOutData();
}

void shiftOutData() {
  digitalWrite(LATCH_PIN, LOW);
  shiftOut(DATA_PIN, CLOCK_PIN, MSBFIRST, data[2]);
  shiftOut(DATA_PIN, CLOCK_PIN, MSBFIRST, data[1]);
  shiftOut(DATA_PIN, CLOCK_PIN, MSBFIRST, data[0]);
  digitalWrite(LATCH_PIN, HIGH);
}