Picture of LINUSBot - Line Follower Robot
The operation of this Robot is quite simple.

Infra-red sensors placed at the front of the chassis  will monitor when our Robot is over a black line or when it is over a white background.
In this project we will use the appropriate rounded chassis to the Robot.
In case the robot being on the black line, it will always go ahead, and in the case of out of line and fall into a white area, it will determine whether to correct to the left or right, and thus remain on the black line.

The sensors that will be used is  the array infrared sensor Pololu (also called reflectance sensors) QTRx8RC, that consists of eight sensors (only five are used) QRE1113GR.

This array has a digital output and can easily be managed using the appropriate library of Pololu, for determine the position of the line relative to the sensors.

This array of sensors can be broken in a array with 6 sensors and another with 2 sensors.
For more information about the sensors array , visit:

In this first project, we will use a raw control for our robot, ie we are concerned to keep the robot following the line ...
The Robot will run in a track and we will note that the motions of the robot will be somewhat "robotic", ie: not very smooth, but jerky.

See for more projects.
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Step 1: The track

Picture of The track
Pista 2.jpg
The track will be made of a piece of white cardstock and black electrical tape.
The bend ought to a minimum diameter 6" or greater.
Below we have two examples of track

Step 2: Hardware and Components

Picture of Hardware and Components
ball caster.jpg
1 X Arduino UNO, Mega, Duemilanove or Teensy + + 2.0
1 x prototype shield (optional) (highly recommended)
1 x dual H-BRIDGE
2 x Gear Box with 30:1 of ratio transmission and associated DC motor
2 x wheels 3"
2 x 9V Batteries 400 mA / h
2 x 9V battery clip
1 x Ball caster (third wheel)
wires and cables for connections
screws, nuts, washers, spacers for mounting
2 x acrylic parts for cutting the chassis
tools in general
sahmed711 month ago
Can you please send me the code and library for the line follower robot you built? I'm still on the learning stage and this would help me a lot.
I've send an request via email which is
Thanks in advance.

,hello , can you please send me the code on

BIGDOG1971 (author)  ibraheem.alkaebi2 months ago
Hi Ibraheem,

Request the ocde and libraries by sending an email to


Marcelo Moraes
NitishK22 months ago

for coding:

Nandev9 months ago

Hello, can you please send me the code on

BIGDOG1971 (author)  Nandev9 months ago
As you have requested, the code and libraries are sent for you.
Check your email inbox, please.


Hello BIGDOG1971 and or Nandev, could one of you send me the libraries for this project. Much appreciated.

ihvan35357 months ago

Very nice project! ,hello , can you please send me the code on

achand810 months ago

You zip tied the motors to the chassis? I am looking for a way to fix it to the chassis

BIGDOG1971 (author)  achand810 months ago
Hi Achand8,
Yes, in a first instance, I zipped and tied the motors to the chassis but after I glued the motors to the chassis (in the acrylic version).

I hope I have helped you.

Feel free to send me comments/questions/problems.

Best Regards

Marcelo Moraes
achand8 BIGDOG197110 months ago

I am trying to make this one from scratch and I want mine to go fast like 3pi, around 400 rpm. I am looking for better ways to mount to motors to the acrylic. Something like this!

mortezaab1 year ago

Send me an email and I will provide you the ".ino" file.

jrd2101 year ago
Interesting but getting to the download of software is a nightmare, can you just add the *ino to the pdf??
BIGDOG1971 (author)  jrd2101 year ago
Send me an email and I will provide you the ".ino" file.

Have a look at a new concept - A wall follower robot
CPRSJ2 years ago
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