Timers for a wait list w/o circular referencing

So I am looking for a alternative way to create timers than what I have done. I currently use circular referencing to create timers and as you can imagine circular references are volatile at best in most cases.

What I am doing is I have a queue where employees add themselves, they can only remain in the queue at the top for up to 20 minutes. After the time has expired or they are manually removed the timer starts again for the next person in the queue. This is currently done by one column listing the number in queue that the employee is. When someone is listed as number 1 the timer starts, when their time has passed or they are listed as taken off that number becomes a ZERO and the next person becomes number 1. This works currently but it requires me to keep the workbook open at all times for it to not malfunction. I am looking for a more simple alternative. Keep in mind that using onEdit will not work because when a timer runs out the formulas make the changes and it is not considered a worksheet edit. Because of this the onEdit script does not trigger. Anyone have any ideas?

Go PRO. Pro apps refresh in the background.

I am Pro. I think your misunderstanding whats going on here. The app updating in the background has nothing to do with it. I need a timer to automatically run and reset itself regardless of whether or not someone has input data.

It will start counting down 20 minutes again when the last person’s 20 minute timeframe has ended. If they remove themselves from the list the timer will start at that point in time instead of the 20 minute time out.

No, I understood. Pro apps update the sheet every minute in the background without anyone doing anything to the sheet, that was the basis for my suggestion.

I guess it depends on how you have your timer built. I personally have no experience with this, but did find these in a google search - maybe one of them can give you the missing piece. Good luck.

Tim, thank you for looking and taking your time. These timers still require someone to manually start and stop them. As I mentioned I came up with a way to do this w/o that but it is just not the most streamlined. I fear there is actually no way to do this other than the way that I did it. If you would like to know how I did it I can send you a sample of the formulas in the cells. It takes 5 cells working with one another using 4 circle references with one cell referencing itself as well.