Unfortunately, at least as far as I understand it, you cannot use a simple 555 circuit to rapidfire the PS3 controller. The xbox 360 controller could use it, because the triggers are driven high or low when the trigger is pulled. However, the PS3 controller uses a serial polling system that puts multiple buttons/triggers on the same line, and it loops through them, checking the status one at a time. In order to rapidfire the PS3 controller, you have to have something synced with the looping of the signal that checks the buttons/triggers, then manipulate the trigger at the right time. There is a code in the free code section of this forum that works for the PS3 controllers, and is programmed onto a 12f683 microchip.