The output of the timer is normally low,
if the button is pressed, then the output goes high for t1 seconds.

If the button is pressed for longer than t1,
then the output will remain high untill the button is released.
Please see the Alternative Circuit if this is a problem.

t1(secs)=1.1*Ra*C/1000
Where R is in K Ohms and C is in uF (micro Farads).