What are some good catchers drills you can do alone?

my AAU team is winning nationals(or placing very high in them) every year so they are obviously very good. but i am the closing/ MR pitcher and i and second/third catcher. since its the off season i want to work on getting at least some more play time as catcher. i don't have much room in my house to throw a ball around and nobody to play catch with so i need to find out some drills i can do alone that will get me better.