Use 2ft cage with a door on end. Get 3 feet of fishing line. Lay cage on side. With door closed you should have to lift it up to open. Use a small stick, prop door up. Tie line to stick and food. Put a rock on top of door and both ends of line to the food and stick.
Using a section of heater pipe, cover the bottom with wire mesh. Nail the pipe to a tree, and put corn in the bottom. Squirrels will climb in, not out!