Tomb Raider: Anniversary

The dart shooters are located in the first level of the game, you will not encounter them until you go though the big doors and into the cave of the mountain. So as you enter the cave run forwards until you step onto a pressure pad, stepping on this initiates the dart trap. To disarm them you need to pull two switches.

Walk forwards until you just step off of the pressure pad & turn to the left to face the wall. On here is a ledge, you simply need to make your way up this ledge to your first switch that you need to pull. After you have done that jump from the ledge you are on to the ledge on the opposite wall, now shimmy your way around the wall and down to the second switch. Pull it and the darts will stop earning you the trophy.