A digital pen converts handwritten analog information into digital data that can be uploaded to a computer and displayed or used in applications. Digital pens use different technologies like accelerometers, active components, positional tracking, cameras, or trackballs to detect pen movement and pressure and transmit this data to a device. Digital pens allow handwritten notes and drawings to be created digitally and utilized digitically.

1. INTRODUCTION
• 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) and
used in different applications or just as graphics.

2. TECHNOLOGY GROUPS
• Accelerometer- Accelerometer-based digital pens contain
components that detect movement of the pen and contact
with the writing surface.
• Active- Active pens, such as N-trig's DuoSense Pen™, include
electronic components whose signals are picked up a mobile
device's built-in digitizer and transmitted to its controller,
providing data on pen location, pressure, button presses and
other functionality.
• Positional -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.
• Camera -Camera-based pens use special digital paper to
detect where the stylus contacts the writing surface, such as
those using Anoto technology.
• Trackball pen -Trackball pens use a sensor that is located on
the pen to detect the motion of the trackball.

3. ELECTRONIC PEN