My issue is I want to know when my dog goes in and out of the pet door, I have about 20% of my hearing so those loud annoying audible devices won't work, lol! So here's my idea, I want to use a magnetic door contact from a home alarm system, a relay, a plug-in power supply and a LED! The LED, relay and power supply will be hardwired to my office and the magnetic door contact will be obviously be at the pet door! I don't need a latching circuit, I just want the LED to light up when the door opens then off when closed! I'm not sure what kind of relay I need or how to wire it all up! Sounds simple enough so can you guys help me out?