About this, if you use a variable instead of constant when you check the elapsed time on a timer, you can change the value of this variable within your program, no need to recompile.
A simple method is INCREASE and DECREASE buttons than can change the value of your variable. Start at a default value, then an LCD is practical to display the new value of the variable. Using multiple pairs of buttons make changes easier; one pair for change of 1, one pair for 10, one pair for 100, whatever your needs are.
You might only need buttons that set at specific values.
Robert
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