Where's My Car

I posted this idea on Facebook but thought I would enter in here also..Have you ever walked around a parking lot looking for your car and by the way hoping no one would see that you have lost your car cus you feel like a dummy, or tried to get into someone elses car? Well I have a great idea just dont have the know how to get it done..Have a antenna ball or something simular to put onto the top of your car antenna and a item on your key chain ( like a key fob) that when you push it your antenna would blink so when you came out of the store all you would have to do is push your button and your antenna on your car would blink for you and you could find it without anymore shame :)