There is a variety of different input technologies for IWBs. Choosing between them can be difficult – they all have their own advantages and disadvantages. In the end, the decision will depend on your own requirements and the challenges of your teaching environment.
Resistive Touch Based IWBs
This type of board registers pressure against the screen. This means you can use a stylus or a finger, but you should not use a sharp instrument which could scratch the surface.
The board’s surface deforms slightly under pressure, which closes an electrical circuit. This allows the board to pinpoint the exact area touched with a high degree of accuracy. Different degrees of pressure can be detected, too. So the user can simulate mouse clicks by increasing the pressure.
There are also multi-touch variants of this technology, which can open the door to more expressive interfaces (think of the ease of zooming into an image on a mobile phone.)
The big advantage of these IWBs is the ease of use. As there is no special stylus to use so students can participate with ease.
However, there is a downside. Although the materials are durable, it is possible for them to be damaged over time. Also, heavy pressure and impacts can damage the sensor grid inside the board. Furthermore, the flexible outer surface is more prone to scratches and dents than other, more rigid IWBs.
Electromagnetic Pen Based IWBs
The electromagnetic pen is a passive device that contains a coiled wire. There is no built-in battery or power source. The IWB contains an array of embedded wires which carry an electrical current. When the pen is brought close to the board, electrical induction creates a small current inside the coil. This current generates a magnetic field, which interferes with the flow of electricity in the array of wires. The sensors detect this interference and accurately locate the coordinates of the pen.
The pen contains a couple of switches which can modulate the induced current within the coil, which can also be detected by the board. This simulates the left and right click mouse events. The technology is similar to an artist’s graphics tablet, which is a proven and mature technology.
The advantage of these IWBs is that the board can be made from a tough, resistive material. The downside is that input is only possible through the stylus. This makes collaborative sessions with students a little awkward, as the stylus must be passed around.