Use the second pulse circuit from an analogue clock, it comes with inbuilt crystal which will make the clock very accurate. Otherwise using 555 timer,it can't count time with accuracy, so all your hard work becomes useless.
Bhai thoda sa dimag lagao or clock ⏰ banao. Main bhi banane wala hu new disital clock cd 4017 ic ki madad se Mere you tube channel ko sports Karo tab diagram milega