and what the MOTION SENSOR(equipment) do?...I trid using it, and nothing came up that I noticed?
It's like a mini uav radar. Just place it down and if anyone is nearby it will reveal them to you. Good for camping or for playing Domination and keeping an eye on a certain place like for example you just took over C and you want to get A so you place a motion sensor near C so you can know if people are trying to take that area over. Of course it doesn't work if the guy is using Ghost perk though.
Only way to avoid being detected by motion sensor is to use Hacker Pro. Ghost only hides you from spy planes, you still get picked up on motion sensor and blackbird as far as I know.
Oh and FAMAS is at the top of everyone's "most killed by" list I'm pretty sure. I used it for the first week or so and got bored with the easy button so I switched to Spas-12 and AK47 for the most part.