Marcin Saj
Published © GPL3+

IN-2 Binary Nixie Clock

Use your Arduino Nano or Particle Photon board and build a binary Nixie clock with 18 x IN-2 Nixie tubes.

BeginnerFull instructions provided4,131
Early Bird - US Based Project
2021 China-US Young Maker Competition
IN-2 Binary Nixie Clock

Things used in this project

Hardware components

IN-2 Binary Nixie Clock
×1
Arduino Nano 33 IoT
Arduino Nano 33 IoT
×1
Arduino Nano Every
Arduino Nano Every
×1
Photon
Particle Photon
×1

Software apps and online services

Arduino IDE
Arduino IDE
Particle Build Web IDE
Particle Build Web IDE

Hand tools and fabrication machines

Soldering iron (generic)
Soldering iron (generic)

Story

Read more

Schematics

IN-2 Binary Nixie Clock - Schematic

Module - Nixie Tube Driver V2 - Schematic

Module - Nixie Power Supply

Datasheet - IN-2 Binary Nixie Clock

Code

NTP IN-2 Binary Nixie Clock - Code Example

Arduino
// IN-2 Binary Nixie Clock by Marcin Saj https://nixietester.com
// https://github.com/marcinsaj/IN2-Binary-Nixie-Clock
//
// NTP IN-2 Binary Nixie Clock Example
//
// This example demonstrates how to connect clock to WiFi and 
// synchronizing (ones per day) RTC DS3231 time module with NTP time server 
// 
// Serial monitor is required to debug synchronization
//
// Hardware:
// WiFi signal
// IN-2 Binary Nixie Clock - https://nixietester.com/project/in-2-binary-nixie-clock/
// Arduino Nano IoT 33 - https://store.arduino.cc/arduino-nano-33-iot
// Nixie Power Supply Module, 2 x Nixie Tube Driver V2 & RTC DS3231 module
// Nixie clock require 12V, 1A power supply
// Schematic IN-2 Binary Nixie Clock - http://bit.ly/IN2-BNC-Schematic
// Schematic Nixie Tube Driver V2 - http://bit.ly/NTD-Schematic
// Schematic Nixie Power Supply Module - http://bit.ly/NPS-Schematic
// DS3231 RTC datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf

#include <RTClib.h>                       // https://github.com/adafruit/RTClib
#include <WiFiNINA.h>
#include <WiFiUdp.h>
#include <RTCZero.h>
#include "arduino_secrets.h"              // Please enter your sensitive data in the Secret tab/arduino_secrets.h                              

const int timeZone = 1;                   // Change this to adapt it to your time zone 
                                          // https://en.wikipedia.org/wiki/List_of_time_zones_by_country

char ssid[] = SECRET_SSID;                // Your network SSID (name)
char pass[] = SECRET_PASS;                // Your network password (use for WPA, or use as key for WEP)
int keyIndex = 0;                         // Your network key Index number (needed only for WEP)

int status = WL_IDLE_STATUS;

unsigned long epochTime;
int numberOfTries = 0, maxTries = 30;

#define timeToSynchronizeTime 3           // Each day at 3AM, the RTC DS3231 time will be synchronize with WIFI time
boolean timeToSynchronizeTimeFlag = 0;

int timeHour = 0;
int timeMinute = 0;
int timeSecond = 0;

RTC_DS3231 rtcModule;                     // RTC module library declaration
RTCZero rtc;                              // Arduino Nano Every and IoT 33 have built in RTC 
                                          // this RTC is used by the WiFiNINA.h library
                                          // But for timekeeping we will use DS3231 RTC module because is more accurate

#define EN_NPS    A3                      // Nixie Power Supply enable pin - "ON" = 0, "OFF" = 1 
#define DIN_PIN   A2                      // Nixie driver (shift register) serial data input pin             
#define CLK_PIN   A1                      // Nixie driver clock input pin
#define EN_PIN    A0                      // Nixie driver enable input pin

// Choose Time Format
#define HH        24                      // 12 Hour Clock or 24 Hour Clock

// Bit numbers declaration for nixie tubes display
//           32  16   8   4   2   1
byte H1[] = {26, 24, 45, 15, 17, 12};     // "1" Hours
byte H0[] = {27, 25, 44, 14, 16, 13};     // "0" Hours
byte M1[] = {34, 28, 43, 19, 10,  8};     // "1" Minutes
byte M0[] = {35, 29, 42, 18, 11,  9};     // "0" Minutes
byte S1[] = {36, 39, 41, 21,  2,  0};     // "1" Seconds
byte S0[] = {37, 38, 40, 20,  3,  1};     // "0" Seconds

// 18 bits for "1", 18 bits for "0" - check clock schematic
// 8 bits for gaps - nixie drivers not connected outputs 
// 2 bits for nixie driver gaps - check driver schematic 

// Nixie Display bit array
boolean nixieBitArray[46]; 

// Millis delay time variable 
unsigned long previous_millis = 0;
unsigned long current_millis = 0;


void setup() 
{
  Serial.begin(9600);
  rtc.begin();
  rtcModule.begin();  
 
  pinMode(EN_NPS, OUTPUT);
  digitalWrite(EN_NPS, HIGH);   // Turn OFF nixie power supply module 

  pinMode(DIN_PIN, OUTPUT);
  digitalWrite(DIN_PIN, LOW);  
    
  pinMode(CLK_PIN, OUTPUT);
  digitalWrite(CLK_PIN, LOW);         
  
  pinMode(EN_PIN, OUTPUT);
  digitalWrite(EN_PIN, LOW);
  
  delay(3000);

  Serial.println("#############################################################");
  Serial.println("---------------- IN-2 NTP Binary Nixie Clock ----------------");
  Serial.println("#############################################################");
  Serial.println();

  SynchronizeTimeWiFi();        // Try to connect to WiFi and synchronize time

  digitalWrite(EN_NPS, LOW);    // Turn ON nixie power supply module
}


void loop() 
{    
  // Check if it's time to synchronize the time  
  if(timeToSynchronizeTimeFlag == 1)
  {
    SynchronizeTimeWiFi();    
  }
  
  // Millis time start
  current_millis = millis();

  // Wait 1 second
  if(current_millis - previous_millis >= 1000)
  {
    // Get time from RTC and display on nixie tubes
    DisplayTime();
    previous_millis = current_millis;      
  }
}

void SynchronizeTimeWiFi()
{
  int i  = 0;

  // Try connecting to the WiFi up to 5 times
  while ((status != WL_CONNECTED) && i < 5) 
  {
    Serial.println();
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(ssid);
    
    // Connect to WPA/WPA2 network. Change this line if using open or WEP network:
    status = WiFi.begin(ssid, pass);

    // Wait 10 seconds for connection:
    // Print progress bar      
    int progressBar = 0;
    
    while(progressBar <= 60)
    {
      Serial.print("#");
      delay(165);
      progressBar++;    
    }
    
    i++;
  }
  
  Serial.println();

  if(status == WL_CONNECTED)
  {
    Serial.println("You are connected to WiFi!");  
    
    // Attempt to WiFi time synchronization
    GetTimeWiFi();
  }
  else if (status != WL_CONNECTED)
  {
    Serial.println("The WiFi connection failed");
    Serial.println("Check your WIFI connection and credentials");
    Serial.println("Next attempt to connect in 24 hours");  
  }
  
  timeToSynchronizeTimeFlag = 0;
  PrintWiFiStatus();  
}

void GetTimeWiFi()
{
  do 
  {
    epochTime = WiFi.getTime();
    numberOfTries++;
  }
  while ((epochTime == 0) && (numberOfTries < maxTries));

  if (numberOfTries == maxTries) 
  {
    Serial.println("Time synchronization is failed");
    Serial.println("Next attempt to synchronize time in 24 hours");
    Serial.println(); 
    delay(3000);
  }
  else 
  {
    Serial.println("Time synchronization succeeded!");
    Serial.println();
    rtc.setEpoch(epochTime);

    timeHour = rtc.getHours() + timeZone;
    
    if(timeHour < 0)
    {
      timeHour = 24 + timeHour;  
    }

    if(timeHour > 23)
    {
      timeHour = timeHour - 24;  
    }
    
    timeMinute = rtc.getMinutes();
    timeSecond = rtc.getSeconds();

    // Update RTC DS3231 module
    rtcModule.adjust(DateTime(0, 0, 0, timeHour, timeMinute, timeSecond));
  }  
}

void PrintWiFiStatus() 
{
  // print the SSID of the network you're attached to:
  Serial.print("SSID: ");
  Serial.println(WiFi.SSID());

  // print your WiFi shield's IP address:
  IPAddress ip = WiFi.localIP();
  Serial.print("IP Address: ");
  Serial.println(ip);

  // print the received signal strength:
  long rssi = WiFi.RSSI();
  Serial.print("Signal strength (RSSI):");
  Serial.print(rssi);
  Serial.println(" dBm");
  Serial.println();
}

void DisplayTime()
{
  DateTime now = rtcModule.now();
  
  timeSecond = now.second();
  timeMinute = now.minute();
  timeHour = now.hour();
 
  //if(timeHour == timeToSynchronizeTime && timeMinute == 0 && timeSecond == 0)
  if(timeHour == 3 && timeMinute == 0 && timeSecond == 0)
  {
    timeToSynchronizeTimeFlag = 1;  
  }
  
  byte timeFormat = HH;
    
  // Check time format and adjust
  if(timeFormat == 12 && timeHour > 12) timeHour = timeHour - 12;
  if(timeFormat == 12 && timeHour == 0) timeHour = 12; 

  Serial.print("Time: ");
  if(timeHour < 10)   Serial.print("0");
  Serial.print(timeHour);
  Serial.print(":");
  if(timeMinute < 10) Serial.print("0");
  Serial.print(timeMinute);  
  Serial.print(":");
  if(timeSecond < 10) Serial.print("0");
  Serial.println(timeSecond);      

  NixieDisplay(timeHour, timeMinute, timeSecond);
}
 
void NixieDisplay(byte hours, byte minutes, byte seconds)
{
  boolean bitTime = 0;

  for (int i = 45; i >= 0; i--)
  {
    // Clear bit array 
    nixieBitArray[i] = 0;  
  }
    
  for(int i = 5; i >= 0; i--)
  {
    bitTime = hours & B00000001;                  // Extraction of individual bits 0/1
    hours = hours >> 1;                           // Bit shift

    if(bitTime == 1) nixieBitArray[H1[i]] = 1;    // Set corresponding bit     
    else nixieBitArray[H0[i]] = 1;

    bitTime = minutes & B00000001;                // Extraction of individual bits 0/1
    minutes = minutes >> 1;                       // Bit shift

    if(bitTime == 1) nixieBitArray[M1[i]] = 1;    // Set corresponding bit      
    else nixieBitArray[M0[i]] = 1;

    bitTime = seconds & B00000001;                // Extraction of individual bits 0/1
    seconds = seconds >> 1;                       // Bit shift

    if(bitTime == 1) nixieBitArray[S1[i]] = 1;    // Set corresponding bit     
    else nixieBitArray[S0[i]] = 1;
  }
    
  ShiftOutData();
}

void ShiftOutData()
{
  // Ground EN pin and hold low for as long as you are transmitting
  digitalWrite(EN_PIN, 0); 
  // Clear everything out just in case to
  // prepare shift register for bit shifting
  digitalWrite(DIN_PIN, 0);
  digitalWrite(CLK_PIN, 0);  

  // Send data to the nixie drivers 
  for (int i = 45; i >= 0; i--)
  {    
    // Send current bit 
    if(nixieBitArray[i] == 1) digitalWrite(DIN_PIN, HIGH);
    else digitalWrite(DIN_PIN, LOW);     
    // Register shifts bits on upstroke of CLK pin 
    digitalWrite(CLK_PIN, 1);
    // Set low the data pin after shift to prevent bleed through
    digitalWrite(CLK_PIN, 0);  
  }   

  // Return the EN pin high to signal chip that it 
  // no longer needs to listen for data
  digitalWrite(EN_PIN, 1);
    
  // Stop shifting
  digitalWrite(CLK_PIN, 0);    
}

Classic IN-2 Binary Nixie Clock - Code Example

Arduino
// IN-2 Binary Nixie Clock by Marcin Saj https://nixietester.com
// https://github.com/marcinsaj/IN2-Binary-Nixie-Clock
//
// Classic IN-2 Binary Nixie Clock Example
//
// This example demonstrates how to set the RTC time, read time from RTC and display on nixie tubes.
// Serial monitor is required to display basic options.
//
// Hardware:
// IN-2 Binary Nixie Clock - https://nixietester.com/project/in-2-binary-nixie-clock/
// Arduino Nano - https://store.arduino.cc/arduino-nano
// Or Arduino Nano Every - https://store.arduino.cc/arduino-nano-every
// Or Arduino Nano IoT 33 - https://store.arduino.cc/arduino-nano-33-iot
// Nixie Power Supply Module, 2 x Nixie Tube Driver V2 & RTC DS3231 module
// Nixie clock require 12V, 1A power supply
// Schematic IN-2 Binary Nixie Clock - http://bit.ly/IN2-BNC-Schematic
// Schematic Nixie Tube Driver V2 - http://bit.ly/NTD-Schematic
// Schematic Nixie Power Supply Module - http://bit.ly/NPS-Schematic
// DS3231 RTC datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf

#include <RTClib.h>           // https://github.com/adafruit/RTClib

#define EN_NPS    A3          // Nixie Power Supply enable pin - "ON" = 0, "OFF" = 1 
#define DIN_PIN   A2          // Nixie driver (shift register) serial data input pin             
#define CLK_PIN   A1          // Nixie driver clock input pin
#define EN_PIN    A0          // Nixie driver enable input pin

// Choose Time Format
#define HH        24          // 12 Hour Clock or 24 Hour Clock

// Bit numbers declaration for nixie tubes display
//           32  16   8   4   2   1
byte H1[] = {26, 24, 45, 15, 17, 12};     // "1" Hours
byte H0[] = {27, 25, 44, 14, 16, 13};     // "0" Hours
byte M1[] = {34, 28, 43, 19, 10,  8};     // "1" Minutes
byte M0[] = {35, 29, 42, 18, 11,  9};     // "0" Minutes
byte S1[] = {36, 39, 41, 21,  2,  0};     // "1" Seconds
byte S0[] = {37, 38, 40, 20,  3,  1};     // "0" Seconds

// 18 bits for "1", 18 bits for "0" - check clock schematic
// 8 bits for gaps - nixie drivers not connected outputs 
// 2 bits for nixie driver gaps - check driver schematic 

// Nixie Display bit array
boolean nixieBitArray[46]; 

// Serial monitor state
boolean serialState = 0;

// Millis delay time variable 
unsigned long previous_millis = 0;

// RTC library declaration
RTC_DS3231 rtc;


void setup() 
{      
  Serial.begin(9600);
  rtc.begin();    
  delay(3000);

  pinMode(EN_NPS, OUTPUT);
  digitalWrite(EN_NPS, HIGH);   // Turn OFF nixie power supply module 

  pinMode(DIN_PIN, OUTPUT);
  digitalWrite(DIN_PIN, LOW);  
    
  pinMode(CLK_PIN, OUTPUT);
  digitalWrite(CLK_PIN, LOW);         
  
  pinMode(EN_PIN, OUTPUT);
  digitalWrite(EN_PIN, LOW);

  Serial.println("#############################################################");
  Serial.println("------------------ IN-2 Binary Nixie Clock ------------------");
  Serial.println("---------------- If you want to set new Time ----------------");
  Serial.println("--------------- press ENTER within 5 seconds ----------------");

  // Millis time start
  unsigned long millis_time_now = millis();
  unsigned long millis_time_now_2 = millis();
    
  // Wait 5 seconds
  while((millis() < millis_time_now + 5000))
  {    
    // Print progress bar      
    if (millis() - millis_time_now_2 > 80)
    {
      Serial.print("#");
      millis_time_now_2 = millis();    
    }

    // Set serialState flag if time settings have been selected 
    if(Serial.available() > 0) 
    {            
      serialState = 1;
      break;  
    }
  }

  Serial.println('\n');
    
  // Clear serial buffer
  while(Serial.available())
  Serial.read();

  if(serialState == 0)
  {
    // Turn on the nixie power module if settings have not been selected
    digitalWrite(EN_NPS, LOW);   
  }    
}


void loop ()
{
  // Set a new time if settings have been selected
  if(serialState == 1)
  {
    SetNewTime();
    serialState = 0;
    
    // Turn ON nixie power supply module
    digitalWrite(EN_NPS, LOW);             
  }    
    
  // Millis time start
  unsigned long current_millis = millis();

  // Wait 1 second
  if(current_millis - previous_millis >= 1000)
  {
    previous_millis = current_millis;      

    // Get time from RTC and display on nixie tubes
    DisplayTime();
  }
}

void SetNewTime()
{  
  Serial.println("------ Enter the TIME without spaces in the HHMM format ------");
  Serial.println("- and press enter when you are ready to send data to the RTC -");
  Serial.println('\n');

  // Clear serial buffer
  while(Serial.available())
  Serial.read();
    
  // Wait for the values
  while (!Serial.available()) {}                      

  // Read time as an integer value
  int hhmm_time = Serial.parseInt();

  // Extract minutes and hours
  byte timeSecond = 0;
  byte timeMinute = (hhmm_time / 1) % 100;
  byte timeHour   = (hhmm_time / 100) % 100;
  
  rtc.adjust(DateTime(0, 0, 0, timeHour, timeMinute, 0));             
}

void DisplayTime()
{
  DateTime now = rtc.now();
 
  byte timeHour = now.hour();
  byte timeFormat = HH;
    
  // Check time format and adjust
  if(timeFormat == 12 && timeHour > 12) timeHour = timeHour - 12;
  if(timeFormat == 12 && timeHour == 0) timeHour = 12; 

  byte timeMinute = now.minute();
  byte timeSecond = now.second();

  Serial.print("Time: ");
  if(timeHour < 10)   Serial.print("0");
  Serial.print(timeHour);
  Serial.print(":");
  if(timeMinute < 10) Serial.print("0");
  Serial.print(timeMinute);  
  Serial.print(":");
  if(timeSecond < 10) Serial.print("0");
  Serial.println(timeSecond);      
  
  NixieDisplay(timeHour, timeMinute, timeSecond);
}
 
void NixieDisplay(byte hours, byte minutes, byte seconds)
{
  boolean bitTime = 0;

  for (int i = 45; i >= 0; i--)
  {
    // Clear bit array 
    nixieBitArray[i] = 0;  
  }
    
  for(int i = 5; i >= 0; i--)
  {
    bitTime = hours & B00000001;                  // Extraction of individual bits 0/1
    hours = hours >> 1;                           // Bit shift

    if(bitTime == 1) nixieBitArray[H1[i]] = 1;    // Set corresponding bit     
    else nixieBitArray[H0[i]] = 1;

    bitTime = minutes & B00000001;                // Extraction of individual bits 0/1
    minutes = minutes >> 1;                       // Bit shift

    if(bitTime == 1) nixieBitArray[M1[i]] = 1;    // Set corresponding bit      
    else nixieBitArray[M0[i]] = 1;

    bitTime = seconds & B00000001;                // Extraction of individual bits 0/1
    seconds = seconds >> 1;                       // Bit shift

    if(bitTime == 1) nixieBitArray[S1[i]] = 1;    // Set corresponding bit     
    else nixieBitArray[S0[i]] = 1;
  }
    
  ShiftOutData();
}

void ShiftOutData()
{
  // Ground EN pin and hold low for as long as you are transmitting
  digitalWrite(EN_PIN, 0); 
  // Clear everything out just in case to
  // prepare shift register for bit shifting
  digitalWrite(DIN_PIN, 0);
  digitalWrite(CLK_PIN, 0);  

  // Send data to the nixie drivers 
  for (int i = 45; i >= 0; i--)
  {    
    // Send current bit 
    if(nixieBitArray[i] == 1) digitalWrite(DIN_PIN, HIGH);
    else digitalWrite(DIN_PIN, LOW);     
    // Register shifts bits on upstroke of CLK pin 
    digitalWrite(CLK_PIN, 1);
    // Set low the data pin after shift to prevent bleed through
    digitalWrite(CLK_PIN, 0);  
  }   

  // Return the EN pin high to signal chip that it 
  // no longer needs to listen for data
  digitalWrite(EN_PIN, 1);
    
  // Stop shifting
  digitalWrite(CLK_PIN, 0);    
}

Particle Photon IN-2 Binary Nixie Clock - Code Example

C/C++
// IN-2 Binary Nixie Clock by Marcin Saj https://nixietester.com
// https://github.com/marcinsaj/IN2-Binary-Nixie-Clock
//
// Photon IN-2 Binary Nixie Clock Example
//
// This example demonstrates how to connect clock to Particle Cloud and 
// synchronizing (ones per day) RTC DS3231 time module with cloud time 
// 
// Serial monitor is required to debug synchronization
//
// Hardware:
// WiFi signal
// IN-2 Binary Nixie Clock - https://nixietester.com/project/in-2-binary-nixie-clock/
// Particle Photon - https://docs.particle.io/photon/
// Nixie Power Supply Module, 2 x Nixie Tube Driver V2 & RTC DS3231 module
// Nixie clock require 12V, 1A power supply
// Schematic IN-2 Binary Nixie Clock - http://bit.ly/IN2-BNC-Schematic
// Schematic Nixie Tube Driver V2 - http://bit.ly/NTD-Schematic
// Schematic Nixie Power Supply Module - http://bit.ly/NPS-Schematic
// DS3231 RTC datasheet: https://datasheets.maximintegrated.com/en/ds/DS3231.pdf

SYSTEM_THREAD(ENABLED);         // Enable automatic connection to WiFi and multi-threading 
#include <RTClibrary.h>

RTC_DS3231 rtcModule;           // RTC module library declaration

int EN_NPS = D5;                // Nixie Power Supply enable pin - "ON" = 0, "OFF" = 1 
int DIN_PIN = D2;               // Nixie driver (shift register) serial data input pin             
int CLK_PIN = D4;               // Nixie driver clock input pin
int EN_PIN = D3;                // Nixie driver enable input pin

// Set your Time Zone e.g. +4, -2, -4.5 (4.5 = 4 hours na 30 minutes) 
// https://en.wikipedia.org/wiki/List_of_time_zones_by_country
double const timeZone = +1;

// Choose Time Format 12/24 hour
int const timeHourFormat = 12;

// Each day at 3AM, the RTC DS3231 time will be synchronize with WiFi time
int const timeToSynchronizeTime = 3;
bool timeToSynchronizeTimeFlag = false;

// Bit numbers declaration for nixie tubes display
//           32  16   8   4   2   1
int H1[] = {26, 24, 45, 15, 17, 12};     // "1" Hours
int H0[] = {27, 25, 44, 14, 16, 13};     // "0" Hours
int M1[] = {34, 28, 43, 19, 10,  8};     // "1" Minutes
int M0[] = {35, 29, 42, 18, 11,  9};     // "0" Minutes
int S1[] = {36, 39, 41, 21,  2,  0};     // "1" Seconds
int S0[] = {37, 38, 40, 20,  3,  1};     // "0" Seconds

// 18 bits for "1", 18 bits for "0" - check clock schematic
// 8 bits for gaps - nixie drivers not connected outputs 
// 2 bits for nixie driver gaps - check driver schematic 

// Nixie Display bit array
bool nixieBitArray[46]; 

int currentHour = 0;
int currentMinute = 0;
int currentSecond = 0;

// Millis delay time variable 
unsigned long previous_millis = 0;
unsigned long current_millis = 0;


void setup() 
{
    Serial.begin(9600);
    delay(5000);                    // Wait for console opening   
    
    rtcModule.begin();              // Setup DS3231 RTC module
    
    pinMode(EN_NPS, OUTPUT);
    digitalWrite(EN_NPS, HIGH);     // Turn OFF nixie power supply module 

    pinMode(DIN_PIN, OUTPUT);
    digitalWrite(DIN_PIN, LOW);  
    
    pinMode(CLK_PIN, OUTPUT);
    digitalWrite(CLK_PIN, LOW);         
  
    pinMode(EN_PIN, OUTPUT);
    digitalWrite(EN_PIN, LOW);  
    
    Serial.println("############################################################");
    Serial.println("-------------- Photon IN-2 Binary Nixie Clock --------------");
    Serial.println("############################################################");
    Serial.println();

    Time.zone(timeZone);            // Set user time zone
    SynchronizeTimeWiFi();          // Time synchronization
    digitalWrite(EN_NPS, LOW);      // Turn ON nixie power supply module
}

void loop ()
{
    // Millis time start
    current_millis = millis();

    // Wait 1 second
    if(current_millis - previous_millis >= 1000)
    {
        // Get time from RTC and display on nixie tubes
        DisplayTime();
        previous_millis = current_millis;      
    }
    
    // Check if it's time to synchronize the time  
    if(timeToSynchronizeTimeFlag == true)
    {
        // Time synchronization
        SynchronizeTimeWiFi();    
    }
}

void SynchronizeTimeWiFi()
{
    Particle.syncTime();
    
    // Check what time format has been chosen 12/24
    if(timeHourFormat == 12)
    {
        currentHour = Time.hourFormat12();
    }
    else if (timeHourFormat == 24)
    {
        currentHour = Time.hour();
    }
    
    currentMinute = Time.minute();
    currentSecond = Time.second();
    
    // Year, Month and Day are not needed
    rtcModule.adjust(DateTime(0, 0, 0, currentHour, currentMinute, currentSecond));
    timeToSynchronizeTimeFlag = false;
    
    Serial.println();
    Serial.println("############################################################");
    Serial.println("------------------- Time synchronization -------------------");
    Serial.println("############################################################");
    Serial.println();
    delay(3000);
}

void DisplayTime()
{
    DateTime now = rtcModule.now();
    
    currentHour = now.hour();
    currentMinute = now.minute();
    currentSecond = now.second();

    NixieDisplay(currentHour, currentMinute, currentSecond);
    
    // Check if it's time to synchronize the time
    if(currentHour == timeToSynchronizeTime && currentMinute == 0 && currentSecond == 0 && Time.isAM())
    {
        timeToSynchronizeTimeFlag = true;  
    }
    
    Serial.print("Time: ");
    if(currentHour < 10)   Serial.print("0");
    Serial.print(currentHour);
    Serial.print(":");
    if(currentMinute < 10) Serial.print("0");
    Serial.print(currentMinute);  
    Serial.print(":");
    if(currentSecond < 10) Serial.print("0");
    Serial.print(currentSecond); 
    
    if(timeHourFormat == 12)
    {
        if(Time.isAM() == true) Serial.print(" AM");
        else if(Time.isPM() == true) Serial.print(" PM");
    }
    
    Serial.println();
}
 
void NixieDisplay(int hours, int minutes, int seconds)
{
    bool bitTime = 0;

    for (int i = 45; i >= 0; i--)
    {
        nixieBitArray[i] = 0;                           // Clear bit array   
    }
    
    for(int i = 5; i >= 0; i--)
    {
        bitTime = hours & 0x00000001;                   // Extraction of individual bits 0/1
        hours = hours >> 1;                             // Bit shift

        if(bitTime == 1) nixieBitArray[H1[i]] = 1;      // Set corresponding bit     
        else nixieBitArray[H0[i]] = 1;

        bitTime = minutes & 0x00000001;                 // Extraction of individual bits 0/1
        minutes = minutes >> 1;                         // Bit shift

        if(bitTime == 1) nixieBitArray[M1[i]] = 1;      // Set corresponding bit      
        else nixieBitArray[M0[i]] = 1;

        bitTime = seconds & 0x00000001;                 // Extraction of individual bits 0/1
        seconds = seconds >> 1;                         // Bit shift

        if(bitTime == 1) nixieBitArray[S1[i]] = 1;      // Set corresponding bit     
        else nixieBitArray[S0[i]] = 1;
    }
    
    ShiftOutData();
}

void ShiftOutData()
{
    // Ground EN pin and hold low for as long as you are transmitting
    digitalWrite(EN_PIN, 0); 
    // Clear everything out just in case to
    // prepare shift register for bit shifting
    digitalWrite(DIN_PIN, 0);
    digitalWrite(CLK_PIN, 0);  

    // Send data to the nixie drivers 
    for (int i = 45; i >= 0; i--)
    {    
        // Send current bit 
        if(nixieBitArray[i] == 1) digitalWrite(DIN_PIN, HIGH);
        else digitalWrite(DIN_PIN, LOW);     
        // Register shifts bits on upstroke of CLK pin 
        digitalWrite(CLK_PIN, 1);
        // Set low the data pin after shift to prevent bleed through
        digitalWrite(CLK_PIN, 0);  
    }   

    // Return the EN pin high to signal chip that it 
    // no longer needs to listen for data
    digitalWrite(EN_PIN, 1);
    
    // Stop shifting
    digitalWrite(CLK_PIN, 0);    
}

Example Code

Credits

Marcin Saj

Marcin Saj

28 projects • 29 followers
I am currently involved in the development of the Flipo.io and NixieTester.com project.

Comments

Awards
Early Bird - US Based Project
2021 China-US Young Maker Competition
Related channels and tags
  • Arduino
  • Clocks
  • Internet of Things
  • Particle
  • Retro Tech