I have 130 ft of lakefront property and am wondering if I can set up a laser or something that would run parallel to the shoreline and sound a signal or alarm when someone crosses over it towards the water. I have 2 young kids and this seems like it would be a good safety feature. I know there are laser sensors that do this in the garage, but this would have to stretch much farther obviously. Or if not a laser beam, possibly another idea?

I am looking for a no contracts apartment home security system.

Theres only one entrance to our apartment as we're on level 2, so the door is the one place that needs covering; I'm looking for something that will make a LOUD noise when the door is opened after I have set the alarm to 'on'.

This may take the form of a laser beam or something similar?

I do have a cat - if she is likely to set it off at night, its not a problem to keep her away in the bathroom, but pls can you state whether the cat would/wouldn't set the alarm off.

Thanks!!!