Monthly Archives: December 2009

R/C Lawnmower

Posted by techfreak on December 15, 2009 No comments

Hack a Day has great articles about hacks from all over the world. This time I want to write about a very interesting project about radio controlled lawnmower.

[center][img]/media/kiwi/uploads/z1-300×224.jpg[/img][/center]

I wanted to build similar lawnmower with the difference that I would use Wiimote for controlling it. But interfering Wiimote directly to an AVR or other micro controller is a bit hard, so I thought of using the laptop to connect Wiimote to a mower. I already made some plans, but then I realized about the biggest problem – danger of using something like this without my direct control over it.

After all, I’m perfectly capable of hurting myself without additional help, so building this could end badly.

Anyway I’m happy that someone actually made something like this, and I have no problems about him using it as long as it’s far away from me. :-D

More: [url=http://hackaday.com/2009/11/14/rc-lawnmower/]http://hackaday.com/2009/11/14/rc-lawnmower/[/url]

Hackers Clone E-Passports

Posted by techfreak on December 11, 2009 No comments

Two RFID researchers created a video showing how an RFID reader attached to an improvised explosive device could theoretically identify a U.S. citizen walking past the reader and set off a bomb. They haven\’t yet tested the theory on a real U.S. passport since the documents have yet to be distributed. They still here show an attack using a prototype passport with RFID chip placed in the pocket of the victim. As the chip passes the reader, the reader detonates an explosive device placed in the trash can.
[youtube]http://www.youtube.com/v/-XXaqraF7pI[/youtube]

RFID on Mythbusters

Posted by techfreak on December 11, 2009 No comments

Adam Savage talks why they didn\’t do an episode about RFID (In)Security on Mythbusters TV show.
[center][youtube]http://www.youtube.com/v/-St_ltH90Oc[/youtube][/center]

(In)Security of RFID Credit Cards

Posted by techfreak on December 11, 2009 No comments

Hacker explains how easy is it to read data from RFID chips which are integrated in newer credit cards. And he talks about risks of having unencrypted data (owner\’s name, credit card number, expiration date, etc.) on these chips. He uses $10 RFID reader from eBay.
[youtube]http://www.youtube.com/v/vmajlKJlT3U[/youtube]

Human implants

Posted by techfreak on December 11, 2009 No comments

Every day people are replacing keys with RFID implants. You can do a lot things easier with RFID, than with keys. Did you ever misplace car keys? With RFID you just need to be in a range of car\’s RFID module and car\’s unlocked.

However, security experts have warned against using tags in that manners because it is really easy to read data from it with almost every RFID reader.

Someone can approach you and scan your tag without your knowledge. Then copy content your card\’s content to writable tag. And he could drive your car, get in your house or/and even in your workplace.
[center][img]/media/rfid/human-implants.jpg[/img][/center]

What is RFID

Posted by techfreak on December 11, 2009 No comments

RFID is the use of an object (RFID tag) applied to or incorporated into a product, animal, or a person for the purpose of identification and tracking using radio waves.

About RFID

Posted by techfreak on December 11, 2009 No comments

[b]Passive RFID tags[/b] (most common): no battery, require an external power source

[b]Active RFID tags:[/b] contain a battery, can transmit signals autonomously and can transmit over longer distances

[b]RFID tags are used for:[/b] – passports – race timing – transportation payments – product tracking – transportation and logistics – animal identification – inventory systems – human implants – libraries

[b]Potential risks[/b]
RFID for authenticating people is very risky due to the way you can read RFID tag. It is possible to read content of RFID tag just by passing by the person who has it implanted.

Wireless power

Posted by techfreak on December 8, 2009 No comments

I stumbled upon an interesting article about wireless transmission of power and thought of sharing it here.

[center][img]/media/kiwi/uploads/b-300×225.jpg[/img][/center]

It’s really simple and cheap way to wirelessly transmit electricity on really short distance. It’s made of big and small coil, a couple of capacitors and LED diode.

More info: [url=http://www.instructables.com/id/Wireless-Power-Transmission-Over-Short-Distances-U/]http://www.instructables.com/id/Wireless-Power-Transmission-Over-Short-Distances-U/[/url]

ffmpeg and x264

Posted by techfreak on December 6, 2009 No comments

How to install ffmpeg with x264 codec support on Debian Lenny (5.0)?

[b]Why is this useful?[/b] By using x264 codec rather than a FLV video format you will gain on video and audio quality.

1. We need to remove any previous ffmpeg installations.

2. Add additional repository to /etc/apt/sources.list

Open file with nano editor:
[quote]nano /etc/apt/sources.list[/quote]
and add following line on the end of the file:
[quote]deb http://www.debian-multimedia.org stable main[/quote]
3. Install needed libraries:

apt-get install build-essential subversion git-core checkinstall yasm texi2html libfaac-dev libfaad-dev libmp3lame-dev libopencore-amrnb-dev libopencore-amrwb-dev libsdl1.2-dev libx11-dev libxfixes-dev libxvidcore4-dev zlib1g-dev libogg-dev

4. Install x264
[quote]git clone git://git.videolan.org/x264.git
cd x264
./configure
make
sudo checkinstall –pkgname=x264 –pkgversion \"1:0.svn`date +%Y%m%d`\" –backup=no –default[/quote]
5. Install libtheora
[quote]wget http://downloads.xiph.org/releases/theora/libtheora-1.1.1.tar.gz
tar xzvf libtheora-1.1.1.tar.gz
cd libtheora-1.1.1
./configure
make
sudo checkinstall –pkgname=libtheora –pkgversion \"1.1.1\" –backup=no –default[/quote]
6. Install ffmpeg
[quote]svn checkout svn://svn.ffmpeg.org/ffmpeg/trunk ffmpeg
cd ffmpeg
./configure –enable-gpl –enable-version3 –enable-nonfree –enable-pthreads –enable-libfaac –enable-libfaad –enable-libmp3lame –enable-libtheora –enable-libx264 –enable-x11grab
make
sudo checkinstall –pkgname=ffmpeg –pkgversion \"4:0.5+svn`date +%Y%m%d`\" –backup=no –default[/quote]
7. Install qt-faststart

Normal mp4 file needs to be fully downloaded before it can be played by Flash Player. qt-faststart fixes this.

Type following command from ffmpeg source directory:
[quote]make tools/qt-faststart[/quote]
Example:
[quote]ffmpeg -i input.mov -acodec libfaac -ab 128k -ac 2 -vcodec libx264 -vpre hq -crf 22 -threads 0 output.mp4
./tools/qt-faststart output.mp4 output2.mp4[/quote]
Now you can play output2.mp4 by any Flash player. LongTail’s freeware [url=http://www.longtailvideo.com/]JW Player[/url] is quite good, has many options and can play both mp4 and flv.

Now you can use ffmpeg to compress videos with x264 codec. [url=http://techsiteblog.com/convert-video-to-flv-with-php/]Read more about converting video with PHP[/url]

Warning: Latest ffmpeg version has some problems with FLV format and it’s impossible to convert video to .flv with it! If you need flv support try installing older version of ffmpeg (if you install it by apt-get install ffmpeg you will be able to convert to FLV but there is no x264 support).

Source: [url=http://ubuntuforums.org/showthread.php?t=786095]http://ubuntuforums.org/showthread.php?t=786095[/url]

Omni-car

Posted by techfreak on December 4, 2009 No comments

I’m interested in omnidirectional wheels from when I watched [url=http://dsc.discovery.com/tv/prototype-this/prototype-this.html]Prototype This![/url], The Discovery Channel TV series. They used these wheels in episode Six-Legged All Terrain Vehicle.

[center][img]/media/kiwi/uploads/a-300×300.jpg[/img][/center]

I thought a few times about building a RC car with these omni wheels, but never got around to even buy needed materials. And of course there is also a lack of tutorials/articles about it on the Internet.

Well, I then forgot about it, but a few days ago I found a post about Omni-car on Hack a Day blog. [url=http://hackaday.com/2009/11/17/omni-car/]http://hackaday.com/2009/11/17/omni-car/[/url]

Really interesting project, but sadly these wheels are a bit too expensive.

Direct link: [url=http://didyoumakethat.webs.com/projects.htm]http://didyoumakethat.webs.com/projects.htm[/url]