hi I'll show you how to hook up a reed switch to your LED light strips so first thing you want to do is have the positive from your LED strip going to the positive on your power supply just like normal and then you have your negative going from the LED strip to the common c om screw terminal on your Reed switch then from the in C or normally closed screw terminal when you read switch you have that go back to your power supply so as soon as we remove this magnet it will close this little switch and we'll have a complete circuit you'll probably mount this part on the doorframe if you're talking about a closet or a cabinet and you'll probably mount this one on the actual door the part that moves since there's no wires when the magnet gets closed goes off move the magnet away it comes back on so very simple to wire up to simply interrupt your negative go to the comm and then go from the normally closed terminal back to your supply I have a link in the description of where you can buy these