PS3 controller's motion sensor doesn't work?

Question

Now, I got a PS3 a little while ago, and a red light up controller. The PS3 came with a regular controller aswell but, whenever I use the Light up controller, the motion sensor is not working. I don't know if it even has one. It's a wireless controller but you have to plug a USB into the PS3.
 

Here's a link to the controller on Gamestop: http://www.gamestop.com/ps3/accessories/ps3-afterglow-controller/69393

Do I have to do something to get this motion sensor to work?
Or does it just have no motion sensor?