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Design and building of a line follower robot

Franklin Jara, Francisco Mendez, Jessica Galvez, Dayana CarrilloEscuela Superior Politcnica de Chimborazo

Riobamba, Ecuador

Franksk8_jara@hotmail.com, , ,

AbstractThis electronic document is a live template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document. DO NOT USE SPECIAL CHARACTERS, SYMBOLS, OR MATH IN YOUR TITLE OR ABSTRACT. (Abstract)Index TermsComponent, formatting, style, styling, insert. (key words)I. Introduction All manuscripts must be in English. These guidelines include complete descriptions of the fonts, spacing, and related information for producing your proceedings manuscripts. Please follow them and if you have any questions, direct them to the production editor in charge of your proceedings (see author-kit message for contact info).II. line follower robot structure

This robot can be divided into several parts:

Sensors

Processor (Arduino) Actuators (Motors and wheels)

Chassis

The electrical circuit of some line follower robots can compare the analog signal received form sensors and then transmit the result to the processor in digit '0' or '1' and some of them send the analog signals to the processor directly and the processor ought to convert them to digital form. Anyway, the analog signals must be converted to the digital form and then the processor can process them.

The main elements of electrical structure are sensors, Analog to Digital Converter, Processor and Motor Driver.

A. The Sensors

Fig.1. The sensor array reflectanceThis kind of robot uses Infrared Ray sensors to find the path and direction; Infrared Ray sensors contain a match infrared transmitter and infrared receiver pair. White surfaces generally reflect well, but while black surfaces reflect poorly.

If the receiver receives the reflection ray, it means that the robot is on white and if it cannot receive it, so the robot is on black. These devices work by measuring the amount of light that is reflected into the receiver. Because the receiver also responds to ambient light, the device works best when well shielded from ambient light, and when the distance between the sensor and the reflective surface is small (less than 10mm). IR reflectance sensors are often used to detect white and black surfaces. White surfaces generally reflect well, but while black surfaces reflect poorly.

The sensor array reflectance fig.1 is used as sensor detector lines but can be used as a proximity sensor or reflectance general purpose, the module brings eight infrared light emitters and receivers (phototransistors) each pair is separated in steps of 0.375 "(9.525mm) each phototransistor is connected to a resistor pull - up to form a voltage divider for obtaining an analog output voltage in the range from 0 VDC - VIN (which typically is 5VDC).

B. Processor (Arduino)

The Arduino is already pre-built out of the box; that will be used later when we finally build the program and test out the robot. This is the brain of the robot; this will hold the code that will allow the robot to follow the line and this will have most of the signal connections plugged in from the motor control board and sensors.Arduinois a family ofsingle-board microcontrollers, intended to make it easier to build interactive objects or environments.The hardware consists of anopen-source hardwareboard designed around an 8 bitAtmelAVRmicrocontroller or a 32-bit AtmelARM. Current models feature aUSBinterface together with six analog input pins and 14 digital I/O pins that can accommodate various extension boards.

Software:

The Arduinointegrated development environment(IDE) is across-platformapplication written inJava, and derives from the IDE for the Processing programming languageand theWiringprojects. It is designed to introduce programming to artists and other newcomers unfamiliar with software development. It includes a code editor with features such assyntax highlighting,brace matching, and automatic indentation, and is also capable of compiling and uploading programs to the board with a single click. A program or code written for Arduino is called asketch.

C. The Actuators (Motors and wheels)

The movement system is an important part of a robot and its objective is how to move robot from one point to another point. This system has some details which show us how to use motors and wheels. There are many kinds of motors and wheels. Our choice is dependent on the robot function, power, speed, and precision.We used two servo motors because, Servo motorshave been around for a long time and are used in many applications.

They are small in size but pack a big punch and are very energy efficient. Because of these features, they can be used to operate remote-controlled or radio-controlledtoy cars,robotsand airplanes. Servo motors are also used in industrial applications, robotics, in-line manufacturing, pharmaceutics and food services. But how do the little guys work?

The servo circuitry is built right inside the motor unit and has a positionable shaft, which usually is fitted with agear(as shown below). The motor is controlled with an electric signal which determines the amount of movement of the shaft.

Usually there are two movement systems for robots:

1. Wheel

2. Tank system

It is better to use wheels for line follower robots. We can use three wheels. Two of them are joined to the motors and installed rear the robot and the other wheel is free and installed front of the robot as a passive caster. Like Fig. 2 which can be seen in below.

Fig.2 Front and rear wheels

Ball Caster

This will be the front-turning wheel that will allow the robot to swivel one way or the other without scraping the chassis. The ball caster is easy to mount; add the spacer to give it enough height so that the platform stays level with the ground (or you can leave it out as long as the sensors that will be mounted are not too close to the ground).

D. The Chassis and Body

Fig.3 fiberglass chassis

There are some good materials for designing robots such as wood, plastic, aluminum and brass alloys. We must pay attention to the resistance, weight and mechanical ability for choosing one of them. There are some agents that we can use them to choose a good body, ability to perforate, incision, flexibility and etc.

In the designed robot, fiberglass fig.3 has been used for chassis because of its lightweight and being strong enough for our project. All components can be installed on the circuit fiber to decrease the weight. For example, motors can be fixed under the fiber and other segments can be installed on the fiber.

The appearance of robot, definitely, is not important. It is noted that the performance is much more important than other things. We have reached to this point that it is better not to use any types of glue for installing components. Therefore, the components can be installed just by screws.

III. conclusions:IV. References:[1] Mehran pakdaman, M. Mehdi Sanaatiyan, Mahdi Rezaei Ghahroudi, A line follower robot from desing to implementation: Technical issues and problems, Babol, Iran.[2] Raimund Edlinger, Michael Zauner, Walter Rokitansky, Electronic Platform for Small Robots in Education, Stelzhamerstr. 23,4600 wels, Austria.