Another project I'm working on required a good timer, but the more I read about Arduino, I realized that I couldn't make an accurate timer using an Arduino that was already devoted to other tasks. The Arduino will always lose time if you perform other tasks. The solution was a Real Time Clock
module that keeps perfect time and has a battery backup so it won't reset if the Arduino loses power.
I like to make things modular, so I decided to combine the Real Time Clock module, an LCD screen, and a few thermistors together on one shield to make a sort of all in one "Atomic clock"/Weather station shield.