I have a LED Bar for my project, I need to make the led count down with real time clock but have big problem. That's 80 led pcs.I dosnt know how to control that with arduino.
This is first serious project and apologize for my bad english, I'm thai student I need hlep 
Moderator edit: image attached and linked
I would use a strip of WS2812b LEDs. There are lots of tutorials for using these. They are also known as Neopixels when sold by Adafruit.
Anything else is making a mountain of work for yourself.
Please post pictures correctly for this site, we don't like going off site for images image guide
We do not like cross posts here DO NOT DO IT
I have reported your other post and I expect it will be deleted. While you are at it please read this:-
How to use this forum
nowlovesoi01:
I have a LED Bar for my project,
What LED bar do you have?
A link to spec/data sheet will help.
Thanks.. Tom.. 
@nowlovesoi01, please do not cross-post. Other thread removed.
I'm apologize about my url link photos, this first post.Thank you for every comments ^v^
nowlovesoi01:
I'm apologize about my url link photos
Fixed.
Your other option would be a matrix - 18 pins (so one Uno) can address all these LEDs but it's A LOT of wiring and soldering.
Do you have your LED bar already? If so, please post details.
Or are you still in the design stage? If so, please post requirements for better advice (such as total size and required power/brightness per LED).