• Pointing Devices Overview
• Purpose Behind Having a Pointing Device
• How a Pointing Device Works
• Various Types of Pointing Devices

A.

Transducer: From the Latin (trans = over or across, as in going over a bridge / ducere = to lead) it means to lead across or transfer. In electronics it is the concept of taking a physical attribute or property from the world around us (like pressure, heat, movement, etc...) and converting it into an electronic signal. Your eyes, nose and fingers sense motion, color, smell, texture and heat and convert these sensations into electronic signals that are neuro-chemically transmitted to your brain. Your brain takes the neuro-chemical data that comes via the nerve pathways and reconverts it into the original sensations of the outside world. Much like this response in your body, a transducer converts physical attributes to electronic signals that a computer can use.

Encoder: Webster’s defines this as, “to convert (as information) from one system of communication to another; especially to convert (a message) into code.” This principle of encoding is much like the decoder rings that used to come in your cereal box as a kid. You and your friend had the “special code” whereby you could send an encrypted message from one to another. This would be sent in code and deciphered using the same code on the other end. Similar to this analogy of the kids toy, photo sensors and LED’s within a pointing device take the motion of an encoder wheel as a digital signal (on the inside of your mouse) and convert it into an analog electronic signal, much like binary or Morse code. This analog signal, transferred through the cord of the mouse tail, is re-converted through software on the inside of the computer back into motion – which becomes the motion of a cursor across the screen or an external system device. For reference see the parts of the trackball image and the Encoder pictured right.