Clock with Arduino © GPL3+

Arduino clock, easy to set up, you can set the date and time by the Serial monitor, this projects uses few components only jumpers, Arduino, and display Nokia 5110/3110, and ready

// pin 3 - Serial clock out (SCLK)

// pin 4 - Serial date out (DIN)

// pin 5 - date/Command select (D/C)

// pin 6 - LCD chip select (CS/CE)

// pin 7 - LCD reset (RST)

//Programa : Teste display Nokia 5110 usando biblioteca Adafruit 
//Autor : VINICIUS LOPES 
#include <Adafruit_GFX.h> 
#include <Adafruit_PCD8544.h> 
// pin 3 - Serial clock out (SCLK) 
// pin 4 - Serial date out (DIN) 
// pin 5 - date/Command select (D/C) 
// pin 6 - LCD chip select (CS/CE) 
// pin 7 - LCD reset (RST) 
Adafruit_PCD8544 display = Adafruit_PCD8544(3,4,5,6,7); 
int second,minute, hour, day, mounth,year;  
unsigned long UtlTime;  
void setup()  
pinMode(2,OUTPUT); 
UtlTime=0;   {    
minute=0;    
hour=0;    
day=0;    
mounth=0;    
year=0;    
Serial.begin(9600);    
 display.begin(); 
 display.setContrast(50); // Adjust the display contrast 
 display.clearDisplay();   //Apaga o buffer e o display 
 display.setTextSize(1);  //Seta o tamanho do texto 
 display.setTextColor(BLACK); //Seta a cor do texto       
display.print(" date e hour ");    
display.setCursor(0,10);    
display.print(" com Arduino");    
display.display(); 
delay (5000);  
//Configura o minute    
display.clearDisplay();    
display.setCursor(0,0);    
display.print("minute: "); 
display.display(); 
Serial.print("\nin between minute:");   
while(minute==0)   {      
if (Serial.available() > 0)      
{        
minute= Serial.parseInt();      
}    
}    
display.print(minute);    
display.display(); 
delay(1000);  
//Configura a hour    
display.clearDisplay();    
display.setCursor(0,0);    
display.print("hour: ");    
display.display(); 
Serial.print("\nin between hour:");  
while(hour==0)    
{      
if (Serial.available() > 0)      
{        
hour= Serial.parseInt();      
}    
}    
display.print(hour);    
display.display(); 
delay(1000);     
//Configura o day    
display.clearDisplay();    
display.setCursor(0,0);    
display.print("day: "); 
display.display();    
Serial.print("\nin between day:");    
while(day==0)    
{      
if (Serial.available() > 0)      
{        
day= Serial.parseInt();      
}    
}    
display.print(day);    
display.display(); 
delay(1000);     
//Configura o mês    
display.clearDisplay();    
display.setCursor(0,0);    
display.print("mounth: ");  
display.display();   
Serial.print("\nin between mounth:");   
while(mounth==0)    
{      
if (Serial.available() > 0)      
{        
mounth= Serial.parseInt();      
}    
}    
display.print(mounth);   
display.display(); 
delay(1000);     
//Configura o year    
display.clearDisplay();    
display.setCursor(0,0);    
display.print("year: ");    
display.display(); 
Serial.print("\nin between year:");    
while(year==0)    
{      
if (Serial.available() > 0)      
{        
year= Serial.parseInt();      
}    
}    
display.print(year);    
display.display();    
delay(1000); 
display.clearDisplay();  
}  
void loop()  
{    
if(millis()-UtlTime<0)    
{      
UtlTime=millis();    
}    
else    
{      
second=int((millis()-UtlTime)/1000);    
}    
if(second>59)    
{      
second=0;      
minute++;      
UtlTime=millis();      
if(minute>59)      
{        
hour++;        
minute=0;        
if(hour>23)        
{          
day++;          
hour=0;          
if(mounth==1||mounth==3||mounth==5||mounth==7||mounth==8||mounth==10||mounth==12)          
{            
if(day>31)            
{              
day=1;              
mounth++;              
if(mounth>12)              
{                
year++;                
mounth=1;              
}            
}          
}          
else if(mounth==2)          
{            
if(year%400==0)            
{              
if(day>29)              
{                
day=1;                
mounth++;              
}            
}            
else if((year%4==0)&&(year%100!=0))            
{              
if(day>29)              
{               
day=1;                
mounth++;              
}            
}            
else            
{              
if(day>28)              
{                
day=1;                
mounth++;              
}            
}          
}          
else          
{            
if(day>30)            
{              
day=1;              
mounth++;            
}          
}        
}      
}    
}     
display.clearDisplay();  
delay(1000);  
Serial.print(day);    
Serial.print("/");    
Serial.print(mounth);    
Serial.print("/");    
Serial.print(year);    
Serial.println();       
display.setCursor(0,0);    
display.print("date ");    
display.print(day);    
display.print("/");    
display.print(mounth);    
display.print("/");    
display.print(year); 
display.display(); 
Serial.print(hour);    
Serial.print(":");    
Serial.print(minute);    
Serial.print(":");    
Serial.print(second);    
Serial.print("\n");    
Serial.println();       
display.setCursor(0,10);    
display.print("hour ");    
display.print(hour);    
display.print(":");    
display.print(minute);    
display.print(":");    
display.print(second);  
display.display(); 
char tecla; 
tecla = Serial.read(); 
if(tecla=='1'){ 
digitalWrite(2,LOW); 
} 
if(tecla=='2'){ 
 digitalWrite(2, HIGH); 
} 
}