clock (second and minutes)

i need make clock display second and minutes using arduino UNO R3

do a search in the box at the top of this page for "clock display " or similar, there have been many projects to give you ideas

how i can set timer in arduino

You can either go through the examples and learn gradually, or you can post on the " gigs and collaborations " and see if someone will design it for you for money.

how i can set timer in arduino

Why do you think you need to?

Does this help?

/*
** Arduino sketch to display date, time temperature and humidity.
** Uses LCD2004 display, Tiny RTC and DHT11 temperature and humidity sensor.
** All parts are readily found on eBay
**
** NOTES:
** I2C pins are A4 SDA, A5 SCL on UNO, 20 SDA and 21 SCL on MEGA 2560.
** DHT11 data connects to Pin 12.
** Displays time in 12 hour format.
** Only reads DHT11 sensor every x seconds for smooth time updating
**
**
**
** Written by Kuhntucker
** LICENSE: GNU General Public License, version 3 (GPL-3.0)
*/
unsigned long readint=15; //Read DHT11 every readint seconds.
unsigned long lasttemptime; //Used to restrict reading DHT11 to every readint seconds.
#include <LiquidCrystal_I2C.h>
#include <Wire.h>
#include <RTClib.h>
#include "DHT.h"

#define I2C_ADDR 0x3F // Define I2C Address where the SainSmart LCD is
#define BACKLIGHT_PIN 3
#define En_pin 2
#define Rw_pin 1
#define Rs_pin 0
#define D4_pin 4
#define D5_pin 5
#define D6_pin 6
#define D7_pin 7
LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin);

#define DHTPIN 12 // DHT11 Data Pin
#define DHTTYPE DHT11 // For DHT 11 sensor

DHT dht(DHTPIN, DHTTYPE);
RTC_DS1307 RTC;

void setup()
{
lcd.begin (20,4);
Wire.begin();
RTC.begin();

//Set the clock to the date & time this sketch was compiled.
if (! RTC.isrunning()) {
RTC.adjust(DateTime(DATE, TIME));
}

// Switch on the backlight and prep the LCD
lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE);
lcd.setBacklight(HIGH);
lcd.clear();
lcd.home ();

writetemphumid(0,2); //wwrites initial temp and humidity
lasttemptime=millis();
} //End setup

void loop()
{
writedate(0,0);
writetime(0,1);
if(millis()-lasttemptime>1000*readint) //Reads DHT11 every readint seconds
{
writetemphumid(0,2);
lasttemptime=millis();
}
if(millis()<lasttemptime) //Resets lasttemptime and reads DHT11 on millis() rollover, ~every 49 days.
{
writetemphumid(0,2);
lasttemptime=millis();
lcd.print("did it");
}
} //End Loop

//function to write the time
void writetime(int col, int row)
{
byte timehour;
DateTime now = RTC.now(); //read the clock
timehour = byte(now.hour());
lcd.setCursor (col, row);
if (timehour>12) timehour=(timehour-12);
if (timehour==0) timehour=12;
lcd.print(timehour, DEC);
lcd.print(':');
if (now.minute()<=9) lcd.print("0");
lcd.print(now.minute(), DEC);
lcd.print(':');
if (now.second()<=9) lcd.print("0");
lcd.print(now.second(), DEC);
lcd.print(" ");
if (now.hour()>12) lcd.print("PM "); else lcd.print("AM ");
} //End writetime

//function to write the date
void writedate(int col, int row)
{
int daynumber;
char* weekday[]={"Sunday=0 ", "Monday ", "Tuesday ", "Wednesday ",
"Thursday ", "Friday ", "Saturday ", "Sunday=1 "};
DateTime now = RTC.now(); //read the clock
if (now.hour()==0 && now.minute()==0 && now.second()<2)
{
lcd.setCursor(col, row);
lcd.print(" ");
}
lcd.setCursor(col, row);
daynumber = now.dayOfWeek();
lcd.print(weekday[daynumber]);
if (now.month()<=9) lcd.print("0");
lcd.print(now.month(), DEC);
lcd.print('/');
if (now.day()<=9) lcd.print("0");
lcd.print(now.day(), DEC);
lcd.print('/');
lcd.print(now.year(), DEC);
} //End writedate

//function to write temperature and humidity
void writetemphumid (int col, int row)
{
float h = dht.readHumidity();
float t = dht.readTemperature();
// check if returns are valid, if they are NaN (not a number) then something went wrong!
if (isnan(t) || isnan(h))
{
lcd.setCursor(col,row);
lcd.print("Failed to read from DHT");
}
else {
t=(9.0*t/5.0)+32.0;
lcd.setCursor (col, row);
lcd.print("Temp: ");
lcd.print(int(t));
lcd.print(" F");
lcd.setCursor ( 0, (row+1));
lcd.print("Humidity: ");
lcd.print(int(h));
lcd.print("%");
}
} //Endwritetemphumid

After you Paul .. :slight_smile: