In my backyard I have a couple of motion activated PIR lights. I also have string lights across the yard that need to be plugged in to turn on. What I would like to do is this. I would like to have a "switch" that the motion lights are plugged into. This switch would be always ON except when I press a button turn a knob etc, and then they are OFF but only for a time; i.e. 15 minutes, 30 minutes etc. The purpose for this is that when we plug in the string lights and are enjoying the nice atmosphere those create, we do not want the motion lights triggering on and turning off all the time. But, I also don't want to put the motion lights on a manual switch and then forget to turn them back on and be left out in the dark. There are lots of remote timers to turn things OFF in 15 minutes etc. But I want to turn something off FOR 15 minutes or 30 minutes and then allow it to come back on.
What you probably want is a spring wound timer switch with SPDT (single pole double throw) contacts to install in place of the ordinary light switch that now controls your outdoor motion lights. These are available with timers spanning up to 12 hours. The SPST variety of this switch is the most common and can only switch something ON for a timed interval, but the SPDT variety can either switch something ON or OFF, depending on the leads connected to the load.
One example would be the 2 hour timer by Intermatic, model FD32HW (I am not recommending this particular product. It is just an example.):
Be careful when ordering because the SPST variety of this timer is by far the most common.