An interactive whiteboard is becoming a more common sight in both classrooms and offices around the world. Traditional whiteboards, of course, have been available for several years and simply allow the user to write on the board with marker pen.  An interactive board takes the concept of a traditional board and expands on it greatly. By connecting a computer to both the board and an overhead projector, whatever application is displayed on the computer will be displayed on the board; and by using specialized pens, a student (or somebody leading a meeting etc.) can manipulate the application directly and have the output displayed immediately on the whiteboard.

As the board reflects whatever is on the computer, it can be used for anything a standard display and input (keyboard / mouse) would normally be used for. This includes taking notes, polling the audience in a meeting, displaying images and displaying a presentation.

The way the control-mechanism works can differ between different boards. The first is by use of an infrared pointing device and IR sensor within the board. The board's position in relation to the position of the projected image is calibrated, and then the system can detect where the pointing device is on the board. This allows the user to click buttons, move boxes, take notes etc.

The second main type of board used an electromagnetic pen and compatible sensor. This works in a very similar way to the IR-type board, except in this case is uses an electromagnetic field to judge where the pen is in relation to the whiteboard.

Finally is the resistive touch-type whiteboard. These work in a similar way to a touch screen and can detect where the user is pressing on the board's surface. This provides a major benefit over the other types because there is not a specific pointing implement needed, and the user can touch the screen and control the application with something as simple as a finger if needed.

When comparing the different types, the (prospective) customer should also take note of the way the projector displays an image on the screen. A traditional projector sends its image from across the room onto the screen. This creates a good-quality image; however, it means that if the presenter gets in between the beam of light and the screen, they will cast a shadow. With interactive boards this can cause an issue because the presenter will often be required to step in front of the board to click a button etc.

To remove this problem, there are two types of projector one might consider. The first is called an ultra-short-throw projector. This type can be positioned just above, and very close, to the screen and still create a high quality image. Using this type of projector means the presenter will not need to step in the way of the beam.

The second is called a rear-projection board. In this case, the display will be projected from behind and inside the board, completely removing the problem of somebody standing in the way of the display beam. However, these types of interactive board are often larger and much more expensive than standard devices.

Whatever type of interactive whiteboard is chosen, when used properly, they can significantly improve performance, both in the classroom and in office-environments.