IR Sensor Overview

First and foremost, IR Sensors (ie. Infrared Sensors) are awesome due to the unique nature in which they can act as an I/O switch. For our table project we are using a IR Light Barrier Kit (similar to the one pictured above) in order to detect the presence of a person in the vicinity.

The IR Sensor is split into two parts: The IR Emitter and the IR Detector. The Function of the Emitter is basic; It holds two IR LEDs that are constantly on when in use. The IR
Detector is where the magic works. When set to have its primary LED sensor facing the IR Emitter's LEDs (up to 13ft) it stays in a powered off state, or in terms of a switch, an open switch. As soon as something blocks or breaks the path of the IR lights on the Emitter the state of the Detector is set to on, or a closed switch. When closed it activates a + and - output on the Detector board. For our project this is where we communicate with the Arduino/Motor Shield.

Our Arduino/Motor Shield receives the signal from the IR sensor weather it is in + or - state. When in - state, or LOW state, the Arduino/Motor Shield does nothing. When in + state, or HIGH state, the Arduino/Motor Shield begins to respond. It runs code to then send signals to a stepper motor that it is connected to, which in turn will have effect over the table we have the motor built into.

This is a very basic summary of how the entire process works, but the goal we are focusing on is primarily less headaches and simple functional output.