light pen

1. Advantges:They have extremely good positional accuracy

2. Disadvantges:light pen requires special implementations

3. Disadvantges:sometimes gives false reading due to background lighting in a room

4. Describtion:a light pen is a special surface on a screen sensitive to the tough surface of a pen

5. Disadvantages: small in size so it can get lost easily

6. Advantges:light pens are easy to use