Arduino based boxing work out timer

Failed in my search for a boxing heavy bag work out timer, unless i was to spend over a hundred pounds. 

Also failed to find a DIY build boxing work out timer to copy. Tried a few phone apps, all did not function as required, and most require some kind of payment.

My requirement was to time 3 minutes heavy bag boxing workout, followed by rest for 1 minute, then 3 minutes heavy bag boxing, another 1 minute rest, etc etc up to 12 rounds. I wanted a visual display of which round i was on, and a visual display of how many seconds left of boxing are left in each rounds, along with how many seconds of rest between rounds is left. I also wanted an audible alarm to get my attention when rounds begin and end. I also wanted a start button i could activate with boxing gloves on.

So i purchased a £11 arduino uno R3 and some basic and inexpensive electronics and wrote some code. Once happy, I designed then 3D printed an enclosure and fascia, and soldered it all up. Works a treat. Saved a fortune. I offer all to replicate, and / or modify to your own requirements. I have commented the code with 3 easily changeable variables for round time length, rest time length and number of rounds, so this can easily be modified and used for other fitness activities.