Projection keyboards, sometimes called holographic or laser keyboards, project a virtual keyboard on a flat surface and use an infrared sensor to detect finger placement. The infrared tracker projects a flat plane of IR energy covering the projected keyboard. When the user's finger breaks that plane, the device analyzes its position to determine what key was pressed. These devices commonly use Bluetooth to communicate with smartphones or tablets.
While a virtual holographic keyboard can make it easier to type on a small device, the system can take some getting used to for first-time users. The responsiveness of a holographic keyboard is not always the same as that of a physical keyboard, and the lack of tactile response can be disconcerting at first. In addition, repeatedly striking a flat, hard surface with fingertips can cause pain and repetitive stress injuries. Users should practice typing with a lighter touch to prevent problems when using holographic keyboards for a long period of time.
Virtual keyboards can also be used as different types of controllers. Some models allow users to use a fingertip as a virtual mouse. Virtual piano keyboards are also available, projecting a set of piano keys on the surface instead of a QWERTY keyboard.