Check out this diy timer project for your gym made with Arduino!
This project is a good beginner Arduino project. I wanted a digital timer in my gym that counted up from 00 to 60 seconds and reset. Since I had a spare Arduino Nano and a dual 7-segment display (rescued from a guitar effect pedal) I decided to build my own instead of driving to Wal-Mart.
If you are not interested in the details and just want to see the result, check out the video below. If you watch more than the first 10-15 seconds then you should seriously consider getting hobby. 😉