C-52 EVB is simple robot experiment. Just need to build a 2 wheels robot with L293D H-Bridge driver and IR sensors. Write down your program with c language.

Introduction

One of my student has made a disgraceful robot that used two stepper motors and with a simple IR sensor. Yes, above picture is what I’m talking. Without battery carrying, a little bit torque of the stepper and misalignment of driving shaft, makes it crawling not walking, but first demo, showed quite impressive to me. He said he wrote a couple of program lines using C, his robot can track the black tape. I feel delighted his intention and endeavor. I thought, ” he borrowed me DS5000, expensive one, a soft uController with internal bootloader, why shouldn’t try with our learning board C-52 Evaluation Board instead”. Another one, told me the same day “I found the L293 Push/Pull Four Channel Driver at Ban-Moah, it costs 1.5 US$ “. I’ve been searching this chip for a year.

The MiniBoard, a Motorola 68HC11 Robot Controller board designed by Fred G. Martin, also uses this driver. The day after, I then decided to prepare the page describing how to use C-52 EVB as a robot controller board. I asked my student for competition, build yourselves robot that can track the black tape. Prize for the winner is 100 US$, with a bit condition that the winner must pay for a big party at Soi Jinda’s Somtum (Papaya Salad) shop. And one of the competitor is me. I thought the rule should be conceived roughly by students and technically by me. The picture on that day will put here soon.

Another robot project you can find here:

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Introduction
Once I made this robot to get some study points while I was studying at the Technical High school in Rijswijk, the Netherlands. I made this in my limited free time, that is why it took me about a year to finish the project. A lot of the used techniques where new, so the research took a lot of the time, but is also the reason why this project had great value to me.

Target
Before I started developing the robot I made a few targets:

Stepper motor is very useful for some robots to make their high accuracy movement. How to drive or control your stepper motor? Use this tutorial as your guide….

General Theory of Stepper Motors

An ordinary DC motor will turn around and around as long as power is supplied. No intelligent circuitry is required to drive such a motor, unless you want to slow it down or reverse direction – just apply power and it spins. A stepper motor is very different. If you just feed it power, it will stay where it is. In order to make the motor move, you have to feed it a changing signal. This is best illustrated by thinking of a magnetic compass with electromagnets around it:

Figure 2.7.1 Motor Stepper

The drawing on the bottom shows power applied to the N electromagnet, drawing the compass toward it. On the right, power is instead applied to the E electromagnet, and the needle has rotated toward that side.

Figure 2.7.2. Basic Stepper Motor

Just four electromagnets would give coarse jumpy motion. Now

Block Diagram

The robot uses IR sensors to sense the line, an array of 8 IR LEDs< (Tx) and sensors (Rx), facing the ground has been used in this setup. The output of the sensors is an analog signal which depends on the amount of light reflected back, this analog signal is given to the comparator to produce 0s and 1s which are then fed to the µC.

Left ———— Center ————- Right

Sensor Array

Starting from the center, the sensors on the left are named L1, L2, L3, L4 and those on the right are named R1, R2, R3, R4.
Let us assume that when a sensor is on the line it reads 0 and when it is off the line it reads 1

The µC decides the next move so as to position the robot such that L1 and R1 both read 0 and the rest read 1.

Left ————– Center ————— Right

Desired State L1=R1=0, and Rest=1

Algorithm:

Line Follower ROBOT

Plermjai Inchuay, plermjai@loxinfo.co.th

Award winner from VingPeaw Competition 2543, the robot built with 2051, L293D, and four IR sensors. Simple circuit and platform, quick tracking and easy-understand program using C language.

I designed my robot, which use two motors control rear wheels and the single front wheel is free. It has 4-infrared sensors on the bottom for detect black tracking tape, when the sensors detected black color, output of comparator, LM324 is low logic and the other the output is high. Microcontroller AT89C2051 and H-Bridge driver L293D were used to control direction and speed of motor.