DIY a simple Line Follower Robot

October 15, 2009 by admin · 7 Comments
Filed under: electronics

A Line Follower machine is most probably the very first step of most of the students in the field of Autonomous Robotics. It is obvious that for best outcome; we need 3-4 sensors and a microcontroller. But dont worry if you are not familiar to microcontroller programming and designing. You can design your own Line Follower Robot without using any kind of programmable device like microcontroller. Belive me by some tricks, you can get the outcome nearly similar to that by using Microcontrollers. Here i am going to present a circuit which gives a very fine output for Black line follower. You can see the output in the video.

This robot uses two sensors, based on comparator, LDR & LED and a L293d Dual Hbridge to control motor direction.

As we are using two sensors we can get maximum of 4 output conditions as shown in table below.

Left Sensor	Right Sensor	Decision	Action
White (0)	White (0)	No Error	Move Forward
White (0)	Black (1)	Left Misalign	Stop right motor
Black (0)	White (0)	Right Misalign	Stop Left Motor
Black (1)	Black (1)	Not Possible	Stop both motors

How to make sensors ???

sensors are based on simple comparator logic. The IC used to make sensor modules is LM324 quad Op-Amp. sensor includes a transmitter section consist of a high intensity red LED with current limiting resistance of 330E.