Line Follower Robot

An Arduino based robot with infrared sensors programmed to follow a line

Introduction

During my second semester I participated on a group project to developed a functioning line follower robot with the parts that were already provided. The task was divided into three main parts, one for each member, those parts were:

Design and manufacturing
Programming, troubleshooting and testing
Analytical and research

Due to my previous experience and confidence with Arduino programming I selected the second option: Programming, troubleshooting and testing.

Parts and Materials

Parts provided

The parts that were given to our team were:

One breadboard
Two 6v/15v DC motors
One Arduino (Orange Pip)
One Adafruit motor shield V2
Two plastic wheels
5 infrared Sensors

Extra Parts

We also incorporated and replaced our own selected parts with the aim to improve the robot, those elements were:

XT60-Connectors
Perspex Clear Acrylic Plastic
3 Capacitors
Aluminium rods
4 High Traction Wheels

All Parts

Prototyping, Programming and Testing

Software:

During the programming phase, I wrote 5 different Arduino codes, each code iteration had more improvements than the previous ones. The infrared sensor would send a digital value to the Arduino and based on those values a corresponding function would action the wheels with a pre-set speed and direction.

The reason I wrote 5 different code iterations was because I was testing to find a precise and improved code that would be used on the robot, each code would be test in order to find the most optimal one

Infrared sensor operation diagram

Programming code

Testing

Distance calibration

Manufacturing

Wood frame with motors

Wood frame without motors

Improved motor case holder

Planetary gear wheel Prototype

First finished tank prototype

Frame replaced for Perspex Clear Acrylic Plastic

Higher traction wheels installed

Second finished prototype

Custom Gearbox designed

One of the main challenges was the EMF returning from the motors to the Arduino causing the whole system to be stuck on a loop and stooping all operation, to prevent that I soldered 3 capacitors to both motors. Also the motors had high speed but little torque, so they were improved with a custom gearbox to increase the torque.

Improvements

The tracks were 3D printed but due the PLA material properties the tracks weren't elastic enough, thus making them impractical. They were replaced with high grip wheels.

The original robot design was based on the Ripsaw Tank, the reason being was due the way a tank moves, The higher grip and the ability to turn 360 degrees on the same position seemed efficient for a robot that needed precise turns.

The plywood chassis was also replaced for a Perspex Clear Acrylic Plastic, the reason was because of its higher strength and robustness.

Perspex Clear Acrylic Plastic Chassis

Ripsaw Tank

Failed 3D printed track

Finished model

Reflection

Sadly, I couldn't test and record the robot because of the gearbox broke before the presentation and testing day. If I could had improve this robot, I would had upgraded the code with PID for precise and quick line reading and movement, designed a better gearbox, replaced the motors for less power consumption ones and higher torque therefore eliminating the need for a gearbox. Installed a more efficient and easy to use motor driver.

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