Simple newbie camera question

I playing around with BGE and I’m trying to create a simple room (four bare walls, floor, ceiling) with the camera inside and the ability to move the camera around with the arrow keys. So, I took the default Blender cube, scaled it up until the camera and light where inside the box. I also changed the material on the four walls so I can tell the difference between the walls and the floor. I Inverted the normals on the box so that it’ll render the inside of the box, and then set sensors and actuators on the camera to respond to left / right arrows to rotate the camera and up / down arrows to move forward and backwards. So far so good and very easy.
Now the tricky part, I want to stop the camera from going outside the box. So I make camera and the box both static actors and I add another condition to the up / down arrow controls to check for touch (or collision - I’m still not sure what the difference is) and set it to filter to the material on the walls and, it doesn’t work. I can still go straight through the walls! What’s the right way to do this?
The closest I got was setting the camera to dynamic (rather than static) which does stop it going through the wall, but also makes it subject to gravity which causes it to fall to the floor first (from about the middle of the room).

Well, with the camera set to dynamic, you can set the Damp to 1.
That should free it from gravity…

That’ll work. Thanks!