ROBOTICS

ROBOTICS TUTORIAL 1- HOW TO USE L293D MOTOR DRIVER IC

ROBOTICS PROJECT 1- MAKING A LINE FOLLOWER ROBOT WITHOUT USING MICROCONTROLLER

ROBOTICS TUTORIAL 1- HOW TO USE L293D MOTOR DRIVER IC

Hi…. Friends.. welcome back..!! I am again here with some discussion on L293D motor driver IC , in this article we will discuss how to use L293D in  motor driving applications.L293D is most widely used motor driver IC , it is used in various robotics projects and in other applications where motor driving is required. So lets have a look how we can drive motors using L293D.

                  

PIN DISCRIPTION

L293D IC is a 16 pin IC the function of various pins is as follows-

PIN 1&9- ENABLE PINS

PIN 2,7 & 10, 15- INPUT PINS

PIN 4,5 & 12,13- GROUND PINS

PIN 3,8 & 11, 14 – OUTPUT PINS

PIN 8- VS (+5V)

PIN 16- VSS (VOLTAGE AT WHICH YOU WANT TO DRIVE YOUR MOTOR)

WORKING

The working of L293D is very simple , this IC consists of two H bridges which are capable of driving two motors at a time. Two input are required for driving a motor the connections are as shown-

When A is high and B is low M1 will rotate in forward direction while when A is low and B is low motor will rotate in reverse direction. Similarly we can drive M2 ,using inputs C and D. Thus by changing logic states of inputs the motor rotation direction can be controlled.

PROTEUS SIMULATION

You can understand working of L293D very easily with the help of proteus just implement the proteus design as shown and check the rotation of motor by changing input logic satats.

DOWNLOADS

You can download proteus design file and datasheet of L293D from the links given below-

DOWNLOAD PROTEUS DESIGN FILE

DOWNLOAD L293D DATASHEET

So its all about L293D, in our upcoming posts we will use this IC in various robotics projects.

I hope this article was useful for you guyz………….in case of any query , doubt or critical view just leave a comment. In our upcoming posts we will discuss about some projects using this IC . Stay tuned…….!!

THNX….:  

ROBOTICS PROJECT 1- MAKING A LINE FOLLOWER ROBOT WITHOUT USING MICROCONTROLLER

Hi friend …!! Welcome back…! this time I am here with a very interesting project for robotics beginners, in this tutorial I am going to discuss how to make an autonomous line follower robot without using a microcontroller, so lets have a look how to make your own autonomous robot with intelligence of following a black line on white surface or white line on black surface.

INTRODUCTION

Line followers are the autonomous robots with the capability of following a black line on white surface and vice versa. Basically we use some kind of sensors to detect the color difference between line and surface. In our project we are going to use IR sensors for detail description of IR sensor first of all read this article     BASIC ELECTRONICS PROJECT 6- MAKING AN IR SENSOR

According to the output of sensors we control our motor to control the direction of robot. In this project we are going to make a BLACK LINE FOLLOWER.

REQUIREMENTS

A robust chassis for robot

Two motors

Two wheels

One caster wheel

Two IR sensors

One motor driver IC ( we are using ULN2003A)

IC 7432

And a power supply.

 STRUCTURE OF ROBOT

Attach wheels with motor to the chassis, place sensors at front side at a distance more than width of the black line. Also attach caster wheel at front side between sensors. Structure will look something like this-

ALGORITHM FOR LINE FOLLOWER ROBOT (USING TWO SENSORS)

-Start

-Check for line

-CASE 1-If both sensors are on move forward

- CASE2-If only left sensor is off , turn left till both sensors are on the line

-CASE 3-If only right sensor is off, turn right till both sensors are on the line

These three cases are illustrated in this figure-

ELECTRONIC CONNECTIONS

Now just connect sensors, ICs and motors as shown in the diagram below-

So now our first line follower robot is in action.

In case of any doubt, query or critical view just leave a comment. I am waiting for your comments.

THNX..:)

BASIC ELECTRONICS PROJECT 6- MAKING AN IR SENSOR

Hi..friends ,welcome back……!! This time I am here with some discussion on INFRA RED sensors. IR sensors are most widely used in many electronics and robotics project , so have a look how to make a IR sensors and how to use them.??

INTRODUCTION

IR SENSORS circuit is very important circuit to detect the presence of any object or to distinguish between black and white colors these sensors are most widely used in making a black or white line follower robots. IR emitter detector circuit is very easy to implement and it can be easily used in object detection, motion detection or color sensing.

IR reflective sensors have emitter (IR LED) and receiver (Photo‐Transistor or photo diode). If white surface is present beneath the IR LED or if there is any object, IR rays are reflected and are sensed by the receiver, while in case of no object receiver does not sense IR rays and same is in case of black surface as light gets absorbed and hence receiver does not sense IR rays.

IR SENSOR CIRCUIT 

Here is the circuit which we have to implement for making our IR sensor module just implement circuit and calibrate your circuit with the help of variable resistor for proper result.

now this sensor circuit can be used in so many electronics and robotics projects. In our other posts we will discuss about use of IR sensors in so many projects.

For making a line follower robot with IR sensors just go to this link   ROBOTICS PROJECT 1- MAKING A LINE FOLLOWER ROBOT WITHOUT USING MICROCONTROLLER

I hope this article was useful for you guys..!! 

In case of any doubt, query or critical view just leave a comment. I am waiting for your comments.

 

EMBEDDED SYSTEMS TUTORIAL10- TIMERS IN AVR -TIMER1

Hi friends..!! welcome back this time I am here with some discussion on second part of TIMERS  in avr , this time we are going to discuss about TIMER1. I hope that you have read and understood the previous posts:

Now we are aware with the concepts of AVR so we are moving towards TIMER1. TIMER1 is more or less like TIMER0 so without wasting much time we will simply go through problem statementwe .Once we are done with this, we can proceed to the CTC and PWM modes of operations in subsequent posts.

Problem Statement

This time our task is to flash an LED every 2 seconds, i.e. at a frequency of 0.5 Hz. We have an XTAL of 16 MHz.

Using prescaler and interrupt

So here is the formula.

                TIMER COUNT  = (REQUIRED DELAY/CLOCK TIME PERIOD ) - 1

Given that we have a CPU Clock Frequency of 16 MHz. At this frequency, and using a 16-bit timer (MAX = 65535), the maximum delay is 4.096 ms. It’s quite low. Upon using a prescaler of 8, the timer frequency reduces to 2 MHz, thus giving a maximum delay of 32.768 ms. Now we need a delay of 2 s. Thus, 2 s ÷ 32.768 ms = 61.035 ≈ 61. This means that the timer should overflow 61 times to give a delay of approximately 2 s.

Now it’s time for you to get introduced to the TIMER1 registers (ATMEGA16/32). We will discuss only those registers and bits which are required as of now. More will be discussed as and when necessary.

TCCR1B Register

The Timer/Counter1 Control Register B- TCCR1B Register is as follows.

TCCR1B Register

Right now, only the highlighted bits concern us. The bit 2:0 – CS12:10 are the Clock Select Bits of TIMER1. Their selection is as follows.

Clock Select Bits Description

Since we need a prescaler of 8, we choose the third option (010).

TCNT1 Register

The Timer/Counter1 - TCNT1 Register is as follows.

TCNT1 Register

 It is 16 bits wide since the TIMER1 is a 16-bit register. TCNT1H represents the HIGH byte whereas TCNT1L represents the LOW byte. The timer/counter value is stored in these bytes.

TIMSK Register

The Timer/Counter Interrupt Mask Register – TIMSK Register is as follows.

TIMSK Register

As we have discussed earlier, this is a common register for all the timers. The bits associated with other timers are greyed out. Bits 5:2 correspond to TIMER1. Right now, we are interested in the yellow bit only. Other bits are related to CTC mode which we will discuss later. Bit 2 – TOIE1 – Timer/Counter1 Overflow Interrupt Enable bit enables the overflow interrupt of TIMER1. We enable the overflow interrupt as we are making the timer overflow 61 times (refer to the methodology section above).

TIFR Register

The Timer/Counter Interrupt Flag Register – TIFR is as follows.

TIFR Register

Once again, just like TIMSK, TIFR is also a register common to all the timers. The greyed out bits correspond to different timers. Only Bits 5:2 are related to TIMER1. Of these, we are interested in Bit 2 – TOV1 – Timer/Counter1 Overflow Flag. This bit is set to ’1′ whenever the timer overflows. It is cleared (to zero) automatically as soon as the corresponding Interrupt Service Routine (ISR) is executed. Alternatively, if there is no ISR to execute, we can clear it by writing ’1′ to it.

Code

Now its time for coding its too easy like TIMER0, if you have not gone through TIMER0 please read TIMER0 tutorial first otherwise it will be a bit tough for you.

/*

 * TIMER1.c

 *

 * Created: 1/28/2013 1:59:29 AM

 *  Author: ABHILASH

 */

       #include <avr/io.h>

       #include <avr/interrupt.h>

       // global variable to count the number of overflows

       volatile uint8_t timer_overflow;

       // initialize timer, interrupt and variable

       void timer1_init()

       {

                 // set up timer with prescaler = 8

                 TCCR1B |= (1 << CS11);

      

                 // initialize counter

                 TCNT1 = 0;

      

                 // enable overflow interrupt

                 TIMSK |= (1 << TOIE1);

      

                 // enable global interrupts

                 sei();

      

                 // initialize overflow counter variable

                 timer_overflow = 0;

       }

       // TIMER1 overflow interrupt service routine

       // called whenever TCNT1 overflows

       ISR(TIMER1_OVF_vect)

       {

                 // keep a track of number of overflows

                 timer_overflow++;

      

                 // check for number of overflows here itself

                 // 61 overflows = 2 seconds delay (approx.)

                 if (timer_overflow >= 61) // NOTE: '>=' used instead of '=='

                 {

                     PORTC ^= (1 << 0);  // toggles the led

                     // no timer reset required here as the timer

                            // is reset every time it overflows

            

                            timer_overflow = 0;   // reset overflow counter

                 }

       }

       int main(void)

       {

                 // connect led to pin PC0

                 DDRC |= (1 << 0);

      

                 // initialize timer

                 timer1_init();

      

                 // loop forever

                 while(1)

                 {

                            // do nothing

                            // comparison is done in the ISR itself

                 }

       }

So friends it was all about TIMER1 in AVR , in case of any query doubt or critical view just leave a comment here . in our next tutorial we will discuss about TIMER2 , till then bye…!!

THNX...:)

EMBEDDED SYSTEMS TUTORIAL 9- INTERFACING 128X64 GRAPHICAL LCD WITH AVR

 Hi friends this time I am here with a very interesting embedded systems tutorial, as in last tutorials we learnt about 16x2 LCD interfacing but some times it seems vey difficult to display a huge amount of data on such a small space provided by 16x2 LCD , so there is the solution a powerful 128x64 GRAPHICAL LCD, with a lot of space and facility to display graphics along with alphanumeric data, in this tutorial we are going to learn how to interface a GRAPHICAL LCD with AVR. We  are going to discuss about a ks0108 based LCD interfacing.

What is required??

I am using a HQM1286404 LCD it’s a pretty old one and please don’t be mistaken with newer versions of LCD, if you are using any other version you have to find its datasheet for wiring connections because wiring connections may be different from version to version. I will provide connections for  HQM1286404 LCD only and its pretty hard to get accurate wiring connection , so better consult your datasheet and internet as well. Except this you will need a AVR MCU, I am using ATMEGA 8 here and of course an LCD library  you can find o many libraries on internet but I am giving a best link to download a very nice library written by Mr. Fabian Maximilian Thiele , thanx to him the link for this library is GLCD_LIBRARY

LCD PIN-OUT CONNECTIONS

Here is the correct pin-out of LCD:

1 Vcc

2 GND

3 VCON

4-11 DB0-DB7

12 CS2

13 CS1

14 RESET

15 R/W

16 D/I

17 EN

18 Vee out

19 LED Anode

20 LED Kathode

     

NOTE:- in some cases you will found that your LCD screen is swapped into two halves in such cases just swap the chip select pins and problem will be corrected...:)

LIBRARY USE

The library , which you have downloaded contains to files ks0108.c and ks0108.h  you have to copy these files and have to paste in the same folder wher .c file of your main program is contained and you have to add corresponding header files in the beginning of the program too like

#include "ks0108.h"

#include "ks0108.c"

the .h files contains the information about pin connection and commands you can easily change the connection pin and ports from there .

Getting familiar with commands is just a learning by doing thig more you do more you learn. Just go through  the library to know more about the command its self explaining.

Along with these library files some font files are also provided these fonts must be added by adding corresponding header file in beginning of the program.except these font you can fetch your windows font with the help of this java program GLCDFontCreator2

SOURCE CODE

here is an interesting source code to start with 

#include <inttypes.h>

#include <avr/io.h>

#include <avr/pgmspace.h>

#include "ks0108.h"

#include "ks0108.c"

#include "arial_bold_14.h"

int main(void) {

                   

                    // Wait a little while the display starts up

                    for(volatile uint16_t i=0; i<15000; i++);

                   

                    // Initialize the LCD

                    ks0108Init(0);

                   

                    // Select a font

                    ks0108SelectFont(Arial_Bold_14, ks0108ReadFontData, BLACK);

                    // Set a position

                    ks0108GotoXY(15,10);

                    // Print some text

                    ks0108Puts_P(PSTR("Tech_strong"));

                    // two little circles

                    ks0108DrawCircle(30, 30, 5, BLACK);

                    ks0108DrawCircle(90, 30, 5, BLACK);

                    // again some text

                    ks0108GotoXY(29,38);

                    ks0108Puts_P(PSTR("Tutorials"));

                    // a loading bar

                    for(int x=0;x<128;x++)

                    {

                                        ks0108GotoXY(x,50);

                                        ks0108DrawRect(x, 50, 80, 10, BLACK);

                    }

                    while(1);

}

CIRCUIT DIAGRAM

now just implement this easy circuit burn your MCU with corresponding .hex file and enjoy your GRAPHICAL lcd.

NOTE:- In my program I have changed data port of LCD from PORTA to PORTD so be careful if you are using this circuit connection you will have to change PORTA to PORTD in ks0108.h file of library be careful ….!!

I think it was a useful article for you all in case of any query, doubt or critical view just leave a comment in next tutorial we will discuss about displaying an image on this LCD,… till then bye…!

THNX..:)