We all need clocks so why not make your own in this instructable I'm going to show you how to make a Precision clock once you set will automatically keep track of the current time in the background of everything. While also only needing very little supplies and zero solderings.

Supplies

First, you will need an Arduino but any Arduino will work

Next, you will need an assortment of generic jumper wires.

2 12mm Sparkfun Pushbutton Switches

A traditional Breadboard

and an LCD 1602 16 pin display

Step 1: Wiring

In order for this clock to work you need to wire this in a very specific way or else you will get a bunch of random numbers on the screen rather than the time.

Step 2: The Code

Since we are not using an RTC we the code is going to be a little bit long but thankfully I have done all the hard work for you and provided it here.

Just Copy and Paste this into either the Arduino IDE or the web Editor.

#include "LiquidCrystal.h"

// This defines the LCD wiring to the DIGITALpins const int rs = 2, en = 3, d4 = 4, d5 = 5, d6 = 6, d7 = 7; LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

// Digital LCD Constrast setting int cs=9;// pin 9 for contrast PWM const int contrast = 100;// default contrast

// initial Time display is 12:59:45 PM int h=12; int m=59; int s=45; int flag=1; //PM

// Time Set Buttons int button1; int button2;

// Pins definition for Time Set Buttons int hs=0;// pin 0 for Hours Setting int ms=1;// pin 1 for Minutes Setting

// Backlight Time Out const int Time_light=150; int bl_TO=Time_light;// Backlight Time-Out int bl=10; // Backlight pin const int backlight=120; // no more then 7mA !!!

// For accurate Time reading, use Arduino Real Time Clock and not just delay() static uint32_t last_time, now = 0; // RTC

void setup() { lcd.begin(16,2); pinMode(hs,INPUT_PULLUP);// avoid external Pullup resistors for Button 1 pinMode(ms,INPUT_PULLUP);// and Button 2 analogWrite(cs,contrast);// Adjust Contrast VO analogWrite(bl,backlight);// Turn on Backlight now=millis(); // read RTC initial value }

void loop() { lcd.begin(16,2);// every second // Update LCD Display // Print TIME in Hour, Min, Sec + AM/PM lcd.setCursor(0,0); lcd.print("Time "); if(h<10)lcd.print("0");// always 2 digits lcd.print(h); lcd.print(":"); if(m<10)lcd.print("0"); lcd.print(m); lcd.print(":"); if(s<10)lcd.print("0"); lcd.print(s);

if(flag==0) lcd.print(" AM"); if(flag==1) lcd.print(" PM"); lcd.setCursor(0,1);// for Line 2 lcd.print("Precision clock");

// improved replacement of delay(1000) // Much better accuracy, no more dependant of loop execution time

for ( int i=0 ;i<5 ;i++)// make 5 time 200ms loop, for faster Button response {

while ((now-last_time)<200) //delay200ms { now=millis(); } // inner 200ms loop last_time=now; // prepare for next loop

// read Setting Buttons button1=digitalRead(hs);// Read Buttons button2=digitalRead(ms);

//Backlight time out bl_TO--; if(bl_TO==0) { analogWrite(bl,0);// Backlight OFF bl_TO++; } // Hit any to activate Backlight if( ((button1==0)|(button2==0)) & (bl_TO==1) ) { bl_TO=Time_light; analogWrite(bl,backlight); // wait until Button released while ((button1==0)|(button2==0)) { button1=digitalRead(hs);// Read Buttons button2=digitalRead(ms); } } else // Process Button 1 or Button 2 when hit while Backlight on { if(button1==0){ h=h+1; bl_TO=Time_light; analogWrite(bl,backlight); }

if(button2==0){ s=0; m=m+1; bl_TO=Time_light; analogWrite(bl,backlight); }

/* ---- manage seconds, minutes, hours am/pm overflow ----*/ if(s==60){ s=0; m=m+1; } if(m==60) { m=0; h=h+1; } if(h==13) { h=1; flag=flag+1; if(flag==2)flag=0; }

if((button1==0)|(button2==0))// Update display if time set button pressed { // Update LCD Display // Print TIME in Hour, Min, Sec + AM/PM lcd.setCursor(0,0); lcd.print("Time "); if(h<10)lcd.print("0");// always 2 digits lcd.print(h); lcd.print(":"); if(m<10)lcd.print("0"); lcd.print(m); lcd.print(":"); if(s<10)lcd.print("0"); lcd.print(s);

if(flag==0) lcd.print(" AM"); if(flag==1) lcd.print(" PM"); lcd.setCursor(0,1);// for Line 2 lcd.print("Precision clock"); }

} // end if else }// end for

// outer 1000ms loop

s=s+1; //increment sec. counting // ---- manage seconds, minutes, hours am/pm overflow ---- if(s==60){ s=0; m=m+1; } if(m==60) { m=0; h=h+1; } if(h==13) { h=1; flag=flag+1; if(flag==2)flag=0; }

// Loop end }

Step 3: Schematic (This Isn't Really a Step)

If anyone reading this is a tech nerd here is also a schematic you can look at it go crazy.

Enjoy and have fun and most of all stay fresh.

Introduction: Precision Clock

Supplies

Step 1: Wiring

Step 2: The Code

Step 3: Schematic (This Isn't Really a Step)