Item 4 - PlayStation 2 Controller
The function of the PlayStation 2 controller is to translate the human user's commands to the PlayStation 2 console.
The design of the controller takes many requirements into consideration. Most importantly the controller needs to translate the mechanical inputs of the user into simulated motion within a video game. This is truly the main function of the controller, so without this consideration the controller has little use. In addition, the controller must complete these translations nearly simultaneously with the input command. If too much lag is present in the controller's translation, the usability of the device will be significantly diminished.
Finally, the controller must provide as much realism as possible. To achieve this, the magnitude of the input must provide a varied response to the console. In the PlayStation 2 this is done through pressure sensitive buttons. The result is different commands being sent from the controller based on the pressure of the button press. Rumble motors within the controller also add to this realistic experience by providing a simulated feel of action within the game.
Interaction with Humans - Human Machine Interface (HMI)
The PlayStation 2 controller provides three types of command interfaces for the user. The most obvious interface is the dual joystick control. Based upon the user inputs to these joysticks various commands are sent to the PlayStation 2. Also included in the interface are the twelve pressure sensitive buttons. As mentioned earlier, the force with which these buttons are pressed determines the code sent to the console. The last control interface on the controller is the "Analog" button. This button operates as a toggle switch which turns the Joystick controls on with one press and off with another press.
Interactions with the World - Sensing
Interaction with the outside world is another vital feature of the PlayStation 2 controller. This "sensing" aspect of the controller enables the controller to know which command to send to the console based on the force with which a button is pressed. The controller is also able to sense a rumble code sent from the console to enable and disable the rumble motors. Without these features the realism intended to be built into the controller would be lost.
Also key to the operation of the controller are the rumble motors embedded within the handles of the device. These small DC motors spin weights in the controller to create a rumbling sensation when the console demands such a reaction. By offsetting these weights the motors provide a very unbalanced rumbling in the controller's grips.
The power consumed by the rumble motors, pressure sensors, microchip, and "Analog" light is provide to the controller through the cord to the console. The plug from the console to the wall converts the AC power drawn in to DC power for the rumble motors. Since there is no gearing, the speed of the motors can only be controlled by adjusting the power with which they are provided.
There is no power conversion within the controller. DC power is drawn from the console, so no conversion is necessary to power the controller.
The only motion conversion which occurs in the PlayStation 2 controller is by way of the rumble motors. These motors convert their rotation to intentional vibration by way of the attached weights. The center of gravity of these weights is moved off the rotating axis in order to provide an unstable vibration.
Though it may appear simple on the outside, the PlayStation 2 controller is a relatively intelligent device. It is able to communicate the specific human inputs to the console by correctly analyzing which command is being input and sending the corresponding code to the console. In addition, the controller also monitors the codes sent from the console to the controller in order to start and stop the rumble motors at the proper time.