Explanation:

- Joy stick: An input device used to control video games or computer graphics. Essential for interacting with a computer or gaming console.

- Keyboard: A primary input device used to type text and interact with a computer system.

- Projector: A device that projects visuals onto a surface, primarily used for displaying images or videos. Unlike others, it does not serve as an input device.

- Microphone: An input device that captures audio and aids in voice communication or text conversion.

Projector is the odd one out as it is not an input device. It primarily functions as an output device, unlike the others.

Projector