Looking for a Count Up /Down Library

Projects Programming
1

I have been looking all day for a good Count Up/Down Timer that can do at least Hours:Minutes:Seconds and run multiple timers at the same time.

I need to run three simultaneous timers in total.

1- Count UP Timer for Overall System Up Time.
2- Count Up Timer for Active System Time with Start and Stop.
3- Count Down Timer that can be set to different Intervals and can be Started and Stopped.

Thanks

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3

https://github.com/RobTillaart/Arduino/tree/master/libraries/StopWatch

some background

http://playground.arduino.cc/Code/StopWatchClass