Practical Line Following Robot Documentation

1 Introduction
1.1 Preface
This practical has been established to provide the microcontroller course at the
Vienna University of Technology with an autonomous robot. The robot should be
programmed by students participating in this course. The goal of this practical is
to develop a working prototype suitable for teaching purposes.
Line following is the ability of an autonomous robot to follow a line marked along
the floor. This primary objective should be accomplished in the least amount of
time.
Line Following Robot Documentation 3
1.2 Requirements
These features are mandatory for the robot:
• high extensibility
• low complexity
• low costs
1.3 Goals / Aims
The following points should be heeded to guarantee the best possible acceptance:
• easy to program
• high speed and maneuverability
• cool exterior
1.4 Existing Systems
Line following is a popular topic many robot engineers already dealt with. Therefore
several competitions are held worldwide among line following enthusiasts
each year. Many successful projects are well documented available through the

An extensive research effort has been undertaken to evaluate different solutions
and to avoid design mistakes. Here is a list of ideas gathered during the web
research phase:
From http://robotroomSweet.html:
• Lego compatible shaft for different types of wheels
• eventually place a bargraph on the front (debugging, fun)
• visible light sensors better than IR (tape lines cause trouble)
From http://robotroomSandwich.html:
• fancy headlights, nice exterior (chassis)
• white leds as light source improve different color tracking
From http://elm-chanworks/ltc/report.html:
• smooth steering algorithm
From http://barelloPapers/LineFollowing/:
• algorithms
From http://seattleroboticsencoder/200106/
linerigel.html:
• sensor tips, sample time, noise reduction, data processing algorithms, fast
robot!
From http://wa4dsyrobot/line/:
• schematics and source codes
From http://kmitl.ac.th/~kswichit/LFrobot/LFrobot.htm:
• award winning robot, very slow though
1.5 Application Boundaries
There are many tradeoffs one has to face while designing a robot. For example
there is conflict between speed and durability, because heavy batteries improve
range while reducing the robots maneuverability. High speed turns are always
limited by the grip of tires, because, most important, the laws of physics can never
be broken.
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2 BUILDING THE PROTOTYPE
2.1 Robot features
• 6 line tracking sensors
• 2 H-bridge motor controllers for 2 DC motors
• low dropout voltage regulator
• 8 debug leds (bargraph)
• play/pause switch
• RF transceiver
2.2 Microcontroller
It seems practical to use the ATmega16 controller which is currently used in the
lab. This controller is mounted on a multi-purpose Controller Board.
ATmega16 Features:
Figure 3: controller board
• Advanced RISC Architecture, 16 MIPS
Throughput at 16 MHz
• 16K Flash, 512 Bytes EEPROM and 1K SRAM
• two 8-bit Timers, one 16-bit Timer
• 4 PWM Channels
• 8-channel, 10-bit ADC
Totally it has 32 IO pins, which are protected by serial
resistors on the Controller Board against short
circuits.