In this tutorial I will show you how to make a pair of IR emitter/detector circuits and also how to implement them to follow a line.

Pins Needed: One per emitter/detector circuit

There are many different methods of setting up sensors for line following. The most popular are:

1.V shape, sensors are placed in a V shape

2.row, sensors run across the line

3.two sensors, one on either side of the line

For this tutorial I will use configuration 3. 

I am using the QRD1114 emitter and detector package, but later on I will show you how to use other emitters and detectors. The actual circuit is very simple and requires only a few components

Schematic:

Pseudocode:

take reading1 left (on white)
take reading1 right (on white)
Loop forever
    take reading2 left
    take reading2 right
    If reading2 left < reading1 left
        Turn left until reading2 left not less than reading1 left
    else if reading2 right < reading1 right
        Turn right until reading2 right not less than reading1 left
    else if reading2 right > or = to reading1 right
        go forward
    else if reading2 left > or = reading1 right
        go forward

----More Coming Soon----