Download project source code: أكتوبر 2012

We have discussed many projects in Robotics before including Line Follower Robot. Maze Solving Robot is similar project but before we discuss about this project, we should know about maze and our objective.

What is Maze?

Maze is a type of puzzle with start start and end points including many dead ends.To solve this puzzle we need to find right path in a fastest possible way.

What type of maze we are going to use for our robot?

Usually, this project requires line maze which is black line on a white background.

Our Objective:

We will build a robot which can find its way in a line maze from start point to end point.

Basic Requirements:

Two Motors: Motors will move robot forward(Both motors running) and help it turns towards left(left motor slow and right fast) or right( right motor slow and left fast).

Five Infrared Sensors: Sensors helps robot to find its path and keeps it updated about the line on the floor.With five sensors their are 32 combination possible but many of them are unlikely to occur in our experiment.For ex. 11111(All indicating black) will never occur because their is only one line and this pattern is showing that line on both side of robot including line on which it is moving.

Concept:

Deciding some rules:
Before implementing this project, you should decide some basic rules which robot must follow. For example if robot face a situation of T or Four Way , in which direction it should turn? Some students go for right hand rule where robot always give preference to right hand side and some go for left hand rule, though both rules are correct, you need to select one of them and teach robot accordingly.

Intersection:

Define intersections ( turns except only right and only left) where robot needs to take decisions.

Storing Information:

Robot should store information about Dead ends(180 degree turns where pattern is five zeroes 00000) and Bad turns.

Algorithm:

Step 1). Robot will start from first end and move straight as their is only one line.

Step 2). It will move Left because their is only left direction( no intersection so no storage) where it can move.

Step 3). Move Left again(no intersection therefore no storage)

Step 4). Move Left ( Intersection and we apply Left hand Rule) Store L

Step 5). Take U Turn ( Reached Dead End) Store value becomes LU

Step 6). Take Left Again ( Intersection and applies left hand rule) Store value becomes LUL . We move Left but because we took U turn in fifth step we now know that we should not have taken Step 4) .To avoid this mistake for future we will replace LUL to S.

Step 7). Move Straight ( Intersection again but as we are following left hand rule, we will not turn towards right,instead we will follow straight Path) and stored value becomes SS

Step 8). Turn right ( Only right available therefore no intersection)

Step 9.) Reach Target.

So SS will correctly guide robot in next run.

Useful Links:

Maze Solving Robot
Recursion Solving a Maze
Micro mouse: Intelligent autonomous maze solving robot

Related Video:

More Projects:

Robotics Projects
Mechanical Projects

Download

Today we will learn how to create a simple discussion forum using PHP and MYSQL. This project is big and can't be covered in single post,so I would divide it into four different posts. Today we will discuss about how we can create skeleton of this project.Next week, we will see how we can use advance features such as jquery,ajax,functions and classes with this project.

File Structure:

We will create five files in root folder and one file db.php (Database configuration file) inside config folder.
index.php : This is home_page or our site from where user can sign in
sign_up.php: Its for new users registration
discuss.php: Post topics
reply.php : Post replies
log_out.php:log out user

Tools: Apache, PHP and Mysql (Download Xampp or WAMP)

What we are trying to do?

When we think about discussion forum, we know that we will need one login system and only registered can post and reply inside the forum.So, we will create three pages just for user login and they are index.php(login form), sign_up.php(for registering new users) and log_out.php(to remove session).

Other two pages will be used for discussion;first for submitting topic and other one will be used for replying.

Step 1. Create Databases:

I have created database discussion where we will create four tables:

categories
users
topics
replies

Database: `discussion`

----------------------------------------------------------

--
-- Table structure for table `categories`
--

CREATE TABLE IF NOT EXISTS `categories` (
  `category_id` int(11) NOT NULL auto_increment,
  `category_name` varchar(100) collate latin1_general_ci NOT NULL,
  PRIMARY KEY  (`category_id`)
)

ENGINE=MyISAM

DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=1 ;

-- --------------------------------------------------------

--
-- Table structure for table `replies`
--

CREATE TABLE IF NOT EXISTS `replies` (

  `reply_id` int(11) NOT NULL auto_increment,
  `reply_content` text collate latin1_general_ci NOT NULL,

  `topic_id` int(11) NOT NULL,

  `reply_user_id` int(11) NOT NULL,

  PRIMARY KEY  (`reply_id`)
) ENGINE=MyISAM

DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=1 ;

-- --------------------------------------------------------

--
-- Table structure for table `topics`
--

CREATE TABLE IF NOT EXISTS `topics` (
  `topic_id` int(11) NOT NULL auto_increment,
  `topic_content` text collate latin1_general_ci NOT NULL,
  `category_id` int(11) NOT NULL,
  `user_id` int(11) NOT NULL,
  PRIMARY KEY  (`topic_id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1

COLLATE=latin1_general_ci AUTO_INCREMENT=1 ;

-- --------------------------------------------------------

--
-- Table structure for table `users`
--

CREATE TABLE IF NOT EXISTS `users` (
  `user_id` int(11) NOT NULL auto_increment,
  `user_name` varchar(16) collate latin1_general_ci NOT NULL,
  `password` varchar(16) collate latin1_general_ci NOT NULL,
  PRIMARY KEY  (`user_id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=1 ;

Step 2. Inserting some dummy DATA
Fill in the category table with related subjects or anythings related , I have filled it with physics,chemistry,maths,physics and biology:

INSERT INTO `discussion`.`categories` (`category_id`, `category_name`)

VALUES (NULL, 'physics'),

(NULL, 'chemistry'),

(NULL, 'maths'),

(NULL, 'physics'),

(NULL, 'biology');

Create Admin user with username and password admin:

INSERT INTO `discussion`.`users` (`user_id`, `user_name`, `password`) VALUES ('1', 'admin', 'admin');

Step 2. Coding Each and very project

index.php

<?php session_start(); 
if(isset($_POST['submit'])) { 
include('./config/db.php');
$user_name = $_POST['user_name'];
$password = $_POST['password'];
$user_name = stripslashes($user_name);
$password = stripslashes($password);
$user_name = mysql_real_escape_string($user_name);
$password = mysql_real_escape_string($password);
$sql="SELECT * FROM `users`

WHERE user_name='$user_name' and

password='$password'";
$result=mysql_query($sql); // execute query

// mysql_num_row is a function used to count number of results we get from the above query
$count=mysql_num_rows($result);

// If result matched $user_name and $password, table row must be 1 row
if($count==1){
$sql="SELECT user_id FROM `users` WHERE user_name='$user_name'";
$result=mysql_query($sql); // execute query
$user_id_array = mysql_fetch_array($result); 
$user_id = $user_id_array['user_id'];
// Register $user_name and $user_id and redirect to file "discuss.php"
$_SESSION['user_name'] = $user_name;
$_SESSION['user_id'] = $user_id;
header("location:discuss.php");
}
else {
echo "Please enter correct username and password (check whether capslock is on)";
}

           } 
 ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD

XHTML 1.0 Transitional//EN"

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Discussion forum from iprojectideas.blogspot.com</title>
</head>

<body>

<form action="#" method="post" name="topic_form">
 <label>Username</label><br /> <input name="user_name" type="text" />
<br />
  <label>Password</label><br />
  <input name="password" type="text" /><br />
  <input name="submit" type="submit" value="submit" />
  
  </form>
  <p>New Users <a href="sign_up.php">Sign up now</a></p>

  </body>
</html>

sign_up.php

 <?php session_start(); 
if(isset($_POST['submit'])) { 
include('./config/db.php');
$user_name = $_POST['user_name'];
$password = $_POST['password'];
$repassword = $_POST['repassword'];
$user_name = stripslashes($user_name);
$password = stripslashes($password);
$repassword = stripslashes($repassword);
$user_name = mysql_real_escape_string($user_name);
$password = mysql_real_escape_string($password);
$repassword = mysql_real_escape_string($repassword);
// check for errors
if($user_name == '' || $password == '' || $repassword =='') {
echo "Please fill correct username and password";
}
else if($password != $repassword) {
echo "password does not match , please try again";
}
 
else {
  $sql="SELECT * FROM `users` WHERE user_name='$user_name'";
  $result=mysql_query($sql); // execute query

  // mysql_num_row is a function used to count number of results we get from the above query
  $count=mysql_num_rows($result);

  // if user name does not exist than register this user in our database and redirect him to discussion forum
  if($count==1){
      echo "User name has been already taken, please try again!";
      }
  else {
     $sql = "INSERT INTO `discussion`.`users` (`user_id`, `user_name`, `password`) VALUES (NULL, '$user_name', '$password');";
     $result=mysql_query($sql); // execute query
     if($result) {
     
     // Register $user_name,$user_id and redirect to file "discuss.php"
     // find out user id
     $sql="SELECT user_id FROM `users` WHERE user_name='$user_name'";
     $result=mysql_query($sql); // execute query
     $user_id_array = mysql_fetch_array($result); 
     $user_id = $user_id_array['user_id'];
     $_SESSION['user_name'] = $user_name;
     $_SESSION['user_id'] = $user_id;
     header("location:discuss.php");
        }
     else {
     echo "Error, please try again";
      }
   } // end of inner else

     } // end of outer else
}
     
 ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Sign up | Discussion forum from iprojectideas.blogspot.com</title>
</head>

<body>

<form action="#" method="post" name="topic_form">
 <label>Username</label><br /> <input name="user_name" type="text" />
<br />
  <label>Password</label><br />
  <input name="password" type="text" /><br />
  <label>Re-enter Password</label><br /><input name="repassword" type="text" /><br />
  <input name="submit" type="submit" value="submit" />
  
  </form>
  <p>Already Registered <a href="index.php">Sign in</a></p>

  </body>
</html>

discuss.php

<?php 
session_start(); 
if(!isset($_SESSION['user_name'])) {
header("location:index.php");
}
else {
$user_name = $_SESSION["user_name"];
$user_id = $_SESSION["user_id"];
echo "Welcome $user_name ";
echo "<a href=\"log_out.php\">Log out</a>";
include('./config/db.php'); 
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Discussion forum from iprojectideas.blogspot.com</title>
</head>

<body>
<?php if(isset($_POST['topic'])) { 
$topic = $_POST['topic'];
$category_id = $_POST['category_id'];
$sql = "INSERT INTO `discussion`.`topics` (`topic_id`, `topic_content`, `category_id`, `user_id`) VALUES ('', '$topic', '$category_id', '$user_id');";
$rsd = mysql_query($sql);
echo "Thanks for submitting your topic $topic in $category_id "; 

           } 
else {
?>
<form action="#" method="post" name="topic_form">
 <label>Topic</label><br /> <textarea name="topic" cols="100" rows="5"></textarea><br />
  <label>Category</label>
  <select name="category_id">
  <?php $sql = "SELECT * FROM  `categories`;";
                             $rsd = mysql_query($sql);
                             while($rs = mysql_fetch_array($rsd)) {
                         $category_id = $rs['category_id'];
       $category_name = $rs['category_name'];
        
       echo "<option value=\"$category_id\">$category_name</option>";
       }
 ?> 
 </select><br />
  <input name="submit" type="submit" value="submit" />
  
  </form>
<?php } 
echo"<h3>Submitted Topics:</h3>";
$sql = "SELECT * FROM  `topics` ORDER BY  `topics`.`topic_id` DESC;";
$topics = mysql_query($sql);
while ($row = mysql_fetch_array($topics, MYSQL_ASSOC )){
  $topic_content = $row['topic_content'];
  $topic_id = $row['topic_id'];
  echo "<h3>$topic_content</h3>";
   $sql = "SELECT * FROM  `replies` where `replies`.`topic_id` = $topic_id;";
   $replies = mysql_query($sql);
   while($row = mysql_fetch_array($replies, MYSQL_ASSOC )) {
      $reply_content = $row['reply_content']; 
   echo "<p> $reply_content</p>";
                } // end of while
  echo "<br /><a href=\"reply.php?topic_id=$topic_id\">reply</a><br />";
}

?>
  </body>
</html>

reply.php

<?php 
session_start(); 
if(!isset($_SESSION['user_name'])) {
header("location:index.php");
}
else {
$user_name = $_SESSION["user_name"];
$user_id = $_SESSION["user_id"];
echo "Welcome $user_name ";
echo "<a href=\"log_out.php\">Log out</a>";
include('./config/db.php'); 
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Discussion forum from iprojectideas.blogspot.com</title>
</head>

<body>
<?php if(isset($_POST['reply'])) { 
$reply = $_POST['reply'];
$topic_id = $_POST['topic_id'];

$sql = "INSERT INTO `discussion`.`replies` (`reply_id`, `reply_content`, `topic_id`, `reply_user_id`) VALUES (NULL, '$reply', '$topic_id', '$user_id');";
$rsd = mysql_query($sql);
if($rsd) {
echo "Thanks for submitting your reply $reply. <a href=\"discuss.php\">Return Back</a> to view it. "; }
else {
echo "Error, reply submission fail";
}

           } 
else {
  $topic_id = $_GET['topic_id'];
  $topic_id= stripslashes($topic_id);
  $topic_id = mysql_real_escape_string($topic_id);
echo"<h3>Reply:</h3>";
$sql = "SELECT * FROM  `topics` where  `topics`.`topic_id` = $topic_id;";
$topics = mysql_query($sql);
$row = mysql_fetch_array($topics, MYSQL_ASSOC );
  $topic_content = $row['topic_content'];
  
  echo "<h3>$topic_content</h3>"; ?>
  <form action="#" method="post" name="reply_form">
  <label>Reply</label><br /> 
  <textarea name="reply" cols="100" rows="5"></textarea><br />
  <input type="hidden" name="topic_id" value="<?php echo"$topic_id" ?>" />
  <input name="submit" type="submit" value="reply" />
  </form>
<?php }
?>
  </body>
</html>

log_out.php

<?php 
session_start(); 
if(!isset($_SESSION['user_name'])) {
header("location:index.php");
}
else {
session_destroy();
header("location:index.php");
}
?>

config/db.php

<?php 
$db_host='localhost';
$db_database='discussion';
$db_username='YOUR_DB_USERNAME';
$db_password='YOUR_DB_PASSWORD';
$connection = mysql_connect($db_host, $db_username, $db_password);
if (!$connection){ die("Could not connect to the database: <br />". mysql_error( )); } 
// Select the database
$db_select = mysql_select_db($db_database); if (!$db_select){
die ("Could not select the database: <br />". mysql_error( )); }


?>

Download

Download project source code

السبت، 20 أكتوبر 2012

Maze solving Robot

الاثنين، 15 أكتوبر 2012

Discussion Forum PHP and MYSQL

الاثنين، 1 أكتوبر 2012

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