A digital pen is an input device which captures the handwriting or brush strokes of a user, converts handwritten analog information created using "pen and paper" into digital data, enabling the data to be utilized in various applications. For example, the writing data can be digitized and uploaded to a computer and displayed on its monitor. The data can then be interpreted by handwriting software (OCR) to allow the digital pen to act as a text entry interface and be used in different applications or just as graphics.
A digital pen is generally larger and has more features than a stylus. Digital pens typically contain internal electronics and have features such as touch sensitivity, input buttons, memory, writing data transmission capabilities, and electronic erasers.
Accelerometer-based digital pens contain components that detect movement of the pen and contact with the writing surface.
Active pens, such as N-trig's DuoSense Pen™, include electronic components whose signals are picked up by a mobile device's built-in digitizer and transmitted to its controller, providing data on pen location, pressure, button presses and other functionality.
Position-based digital pens use a facility to detect the location of the tip during writing. Some models can be found on graphics tablets made popular by Wacom, and on tablet computers using Wacom's Penabled™ technology.
Camera-based pens use special digital paper to detect where the stylus contacts the writing surface, such as those using Anoto technology.
Trackball pens use a sensor that is located on the pen to detect the motion of the trackball.