March 11th, 2010 / 5 Comments » / by Ankur Shrivastava
In Dec 2009 at foss.in at the maemo stall i saw a guy control a small toy car through accelerometer on his N900, i thought of replicating that but it just remained in my mind, so last Saturday i finally decided to implement it and went straight to a toy store and bought a toy RF car, one hour of hacking and i was able to control the small car through by phone (Nokia E61i) here is the video of it working.
the concept is simple, i send commands through my phone over wifi to my laptop which controls the car remote, controlling a toy car remote is very easy with a Parallel port and few transistors but laptops don’t have parallel ports, so i used a micro-controller in between to sort that out, so now micro controller controls the car remote by acting on signals received over UART from laptop.
the working is Phone —(WiFi)—>Laptop —(USB/UART)—> Micro controller —(Relays)—> Car Remote —(RF)—> Toy Car
will post details with code sometime later
January 27th, 2010 / No Comments » / by Ankur Shrivastava
LUG Manipal python workshop poster
LUG Manipal is organising a workshop on python, Workshop is aimed at people interested in beginning programming with python.No programming experience required.
Details are ->
Time: 5:30 pm
Place: NLH 103
Date: 29th JAN to 3rd FEB
September 25th, 2009 / No Comments » / by Ankur Shrivastava
Recently i have started coding in C a lot and what i came across from a lot of people is that doing Threading in C is very hard, is it really like that? here is a simple Pthread program that should clear that up
in the above program i have just created 2 threads and passed thr1 ( = 1 ) and thr2 ( = 2 ) values as parameters the function void * thread ( void * ptr ) is executes as a separate thread, we create two thread objects thread1 and thread2, and start threads using pthread_create function passing thread object, function pointer and parameters as arguments, here NULL specifies default attributes for the thread, we can change this by passing pthread_attr_t structure instead of NULL.
we wait for the threads to finish using the pthread_join function
One major problem that is faced by most of the people is of using a library which is not a thread safe library, so you need to be careful about the libraries you use in your program, if not sure about a particular library being thread safe, just assume it not to be thread safe
PS – No updates from a long time as i dont have a proper net connection ….
July 30th, 2009 / No Comments » / by Ankur Shrivastava
i was trying to explain sockets to one of my friend and this is what i used, the code should be self explanatory, this is a very simple application of sockets…
June 25th, 2009 / 6 Comments » / by Ankur Shrivastava
It all started with a failing Student’s Teacher Feedback System, designed by few fourth year students of my college, in oct-nov 2008 the system was not able to scale and everything was reverted back to paper, it was then when i was contacted by a teacher from my Department ( Information and Communication Technology ), regarding if i can improve it.
i asked DJ if he wants to join me and after few weeks of coding there it was Manipal university’s first (working) Feedback System, when the point of hosting it came, i was surprised to find Manipal University has no Linux servers, i mean come on no Linux what are you people click sys admins, then we decided to setup our own server in the department, thus giving Manipal university its first Linux ( fedora 10 ) server.
currently it just hosts the Feedback System, but we are planning to use it as local ( internal ) fedora repository mirror, we need permission from the WiFi provider ION because almost all the students use only WiFi and not LAN, last time we tried we were denied by saying ” You are a threat to our network “, lets see how it goes this time. we will also require people to manage it but i think this can be handled very well by LUG Manipal, some pics
Fedora 10 server in Manipal
Fedora 10 server in Manipal
PS – i am looking for a way to convince them that setting up a mirror will be helpful for them as well as students can anyone suggest me how to go about it??
June 15th, 2009 / 2 Comments » / by Ankur Shrivastava
last week i gave my 250GB HDD to one of my friend and when i got it back it was filled with viruses, it was that virus which creates .exe inside every , since there were a lot of folders in the HDD ( it was 200GB full ) it was practically impossible for me to go and delete every virus in there, so i decided to make a simple script to remove these viruses here it is
May 24th, 2009 / 5 Comments » / by Ankur Shrivastava
Few weeks ago i came across this article on Techcrunch which says tinyurl is worth $46Million (of course before twitter started using bit.ly as default) which made me think how hard is it to make a simple service like tinyurl and i figured out its not hard. so i used apache’s mod_rewrite to rewrite the url and forward the code to a php script ( url.php ) which will then search for the url in database and take the use to the original url and for shorting, url it is inserted into a table with a auto increment primary key and the key is converted to base36 which contains [a-z] and [0-9], making the short code…
First create a database say ’shorturl’
CREATE TABLE IF NOT EXISTS `shorturl` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`url` varchar(300) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
then create file .htaccess where you want your url to be and write
RewriteEngine On
RewriteCond %{REQUEST_URI} \/([0-9a-z]*)$ [NC]
RewriteRule ^(.*) url.php?url=%1 [L]
and to create the url we will use a simple file say create.php
<html>
<head>
<title>Url Shortner</title>
</head>
<body>
<?php
ob_start();
$host=""; //host
$dbuser=""; // database username
$dbpass=""; // database password
$db=""; //database name
$con = mysql_connect($host,$dbuser,$dbpass);
mysql_select_db("url",$con);
if (!isset($_POST['shorten']))
{
echo "<center><h3>Enter the url to shorten</h3><form method='POST'><input type='text' name='url' />
<input type='submit' name='shorten' value='Shorten' /></form></center>";
}
else
{
if (isset($_POST['url']))
{
$url=" ".mysql_real_escape_string($_POST['url']);
if (strpos($url,"http://") or strpos($url,"https://") or strpos($url,"ftp://"))
{
$url=mysql_real_escape_string($_POST['url']);
}
else
{
$url="http://".mysql_real_escape_string($_POST['url']);
}
$q="select * from url where url='{$url}'";
$res = mysql_query($q,$con);
$row=mysql_fetch_row($res);
if (!$row)
{
$query="insert into url set url='{$url}'";
$res = mysql_query($query,$con);
}
$query1="select id from url where url='{$url}' limit 1";
$res=mysql_query($query1,$con);
$row=mysql_fetch_row($res);
echo "shortened url is http://yoursite.com/".base_convert($row[0],10,36);
}
}
ob_end_flush();
?>
</body>
</html>
then our url.php file
<?php
ob_start();
$host=""; //host
$dbuser=""; // database username
$dbpass=""; // database password
$db=""; //database name
$con = mysql_connect($host,$dbuser,$dbpass);
mysql_select_db($db,$con);
if (isset($_GET['url']))
{
$query="select * from url where id ='".base_convert(mysql_real_escape_string($_GET['url']),36,10)."'";
$res = mysql_query($query,$con);
$row=mysql_fetch_row($res);
header("Location: ".$row[1]);
}
ob_end_flush();
?>
April 6th, 2009 / 4 Comments » / by Ankur Shrivastava
This Sunday when i was giving DBUS a look and thinking about all the cool things possible with it, one of my friend came asking how can he control his torrents from anywhere and i thought controlling is ok, do you want SMS updates??, i fired up qdbusviewer and there it was a simple way to get sms notifications of finished torrents using well twitter and ktorrent, so here are the steps
1) setup your cell phone to recieve SMS updates in twitter,
2) get one more twitter account lets say ktorrent, follow ktorrent and turn device updates on,
3) now save the script below say as torrenttwit.py
4) now enter this ktorrent account username and password in the script below,
5) start ktorrent if not already started, now run the script by typing “python torrenttwit.py”
