How to build a Line Following Robot 1 – Identifying the line
May 6, 2011 4 Comments
To follow the line robot need to identify the line first. Well there are few things you can do to identify a black line on white background or vice versa. One way is use LDR array and tracks the light reflection level. Black line will not reflect the light as white color. Or you can use IR beam. In this post I am going to discuss how we can use IR beams to identify the line. Black color will reflect the IR beam but white will not. Setting up your sensors will depend on your design. To keep the things simple you can arrange them linear. To gain speed you can arrange them to an arrow shape. In this example we will use 3 IR sensors and locate them as an arrow. There are several IR types to make the following circuit work you will need 3mm IR receivers. For IR emitters we can use both 3mm and 5mm.
If the width of the line to be followed is 2cm, you can go for the following set up.
Circuit diagram for the IR unit as follows.
The IC LM324 can handle 4 IR sensors. We need only 3 to track the line we will use the 4th sensor to identify obstacles.
We will see how to make the circuit to control the motors in next post.
He conquers who conquers himself 
what is the IR part number?
hi, im very fresh with IR LED. can i ask that, i have make the circuit by following your diagram, the result i get is, i tuning the VR until the signal indicator is ON, but when i facing the sensor to other place, the indicator is still ON, is it have any thing wrong for my circuit?
jass plz send me the report of circuits and layouts of LFR by lm324 on my mail , dhamal.aniket5@gmail.com
can anyone send me the whole project report and circuit diagram of all Ic’s to be connected ‘ also layout of that circuit diagram plz