~ Ijsland

Ijsland.

Reizen

~ Doorhacking: Opening a Door With Your Cellphone

The problem: There is a group of people that want access to Hackerspace Ghent but there is only one remote to open the gate.

The solution: Build a system that reacts to a phone call by opening the gate if the number of the caller is whitelisted.

What you need:

• A BeagleBoard or some BeagleBoard alternative with a Linux distribution running on it. Any server running a unix like operating system should be usable.
• A Huaweii e220 or an alternative GSM that supports (a subset of) AT commands and has a USB port.
• A team of hackers that know how to solder something togeher. E.g. The hardware guys of hackerspace Ghent.
• A python script that reacts to calls.

The Hack: First of all try to get caller id working by following the Caller ID with Linux and Huawei e220 tutorial. If this works you can listen to the serial communication using pySerial and react to a call. The following python code shows the wait for call method:

  
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def wait_for_call(self):
  self.data_channel.open()
  call_id_pattern = re.compile('.*CLIP.*"\+([0-9]+)",.*')
  while True:
    bytes = self.data_channel.inWaiting()
    buffer = self.data_channel.readline(bytes)
    call_id_match = call_id_pattern.match(buffer)
    if call_id_match:
      number = call_id_match.group(1)
      self.handle_call(number)

The handle_call method … handles the call.

The second thing that is needed is a way to send a signal from the beagle board to the remote. Sending a signal from the beagle board using Linux is really simple. The following bash commands initialize, activate and deactivate a pin.

  
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echo 168 > /sys/class/gpio/export
echo "high" > /sys/class/gpio/gpio168/direction
echo "low" > /sys/class/gpio/gpio168/direction

Code, Projecten, en Hackerspace Ghent

gatekeeper.py

~ Jobsopschool.be beter beveiligd

Omdat er op jobsopschool gevoellige informatie te vinden is (bijvoorbeeld C.V.’s van kandidaten) is de beveiliging ervan belangrijk. Om die veiligheid te garanderen werd de vacaturesite voor onderwijzers op een volledig dichtgetimmerde aparte virtuele server geplaatst. Een server met enkel de broodnodige software zorgt voor een veilige en snelle afhandeling van requests.

Ook werd er voor gezorgd dat alle verkeer versleuteld wordt via SSL. De lighttpd webserver server werd geconfigureerd met deze tutorial die de configuratie van lighttpd met SSL bespreekt. Er werd een SSL certificaat van godaddy aangekocht omdat het root certificaat van godaddy in zowat alle browsers aanwezig is en omdat ze een redelijke prijs vragen.

Code en Projecten

~ Caller ID with Linux and Huawei e220

This is the scenario: you have a Huawei e220, a linux computer and you want to react to a call from a set of predefined numbers. E.g. ordering a pizza when you receive a call from a certain number.

The Huawei e220 supports a subset of the AT commands, which subset is an enterprise secret of te Huawei company. So there is no documentation available for the device I bought, thanks Huawei. Anyhow when you attach the e220 to a Linux machine you should get two serial ports:

  
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/dev/ttyUSB0
/dev/ttyUSB1

To connect to the devices you can use a serial client. GNU Screen can be used as a serial client like this: screen /dev/ttyUSB0 115200. The first device, ttyUSB0 is used to control ttyUSB1, so to enable caller ID on te Huawei e220 you need to send this message to ttyUSB0:

  


  
AT+CLIP=1

To check for calls you should listen to ttyUSB1. A serial session for ttyUSB1 looks like:

  
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^BOOT:44594282,0,0,0,6
^RSSI:18
RING
+CLIP: "+33499311152",145,,,,0
^BOOT:44594282,0,0,0,6

The RING and CLIP messages are the most interesting. The RING signifies an incoming call, the CLIP is the caller ID. The BOOT and RSSI are some kind of ping messages. The following Python script demonstrates a complete session that enables caller ID, waits for a phone call and prints the number of the caller.

  
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#!/usr/bin/env python
import serial, re

command_channel = serial.Serial(
        port='/dev/ttyUSB0',
        baudrate=115200,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS
)
command_channel.open()
#enable caller id
command_channel.write("AT+CLIP=1" + "\r\n")
command_channel.close()

ser = serial.Serial(
        port='/dev/ttyUSB1',
        baudrate=9600,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS
)

ser.open()

pattern = re.compile('.*CLIP.*"\+([0-9]+)",.*')

while 1:
        buffer = ser.read(ser.inWaiting()).strip()
        buffer = buffer.replace("\n","")
        match = pattern.match(buffer)
        if match:
                number = match.group(1)
                print number

Code, Projecten, en Hackerspace Ghent

~ YIN Pitch Tracker in JAVA

To make Tarsos more portable I wrote a pitch tracker in pure JAVA using the YIN algorithm based on the implementation in C of aubio. The implementation also uses some code written by Karl Helgasson and Teun de Lange of the Jazzperiments project.

It can be used to perform real time pitch detection or to analyse files. To use it as a real time pitch detector just start the JAR-file by double clicking. To analyse a file execute one of the following. The first results in a list of annotations (text), the second shows the annotations graphically.

  
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java -jar pitch_detector_yin.jar  flute.novib.mf.C5B5.wav
java -jar pitch_detector_yin.jar  --file flute.novib.mf.C5B5.wav

The provided flute sample is from The Musical Samples library of the University of Iowa and converted to mono wav. The source code of the pitch tracker can be found below.

Muziek, Code, Cultuur, en Projecten

pitch_detector_yin.jar, pitch_detector_yin_src.zip, en flute.novib.mf.C5B5.wav

~ Boids 3D with Processing

Code, Projecten, en Portfolio

boids_windows.zip, boids.png, boids_macosx.zip, boids_linux.zip, boids_src.zip, peasycam.jar, Boids.jar, core.jar, en loading.gif

~ Order Pizza with USB Pizza Button

Recently I bought a big shiny red USB-button. It is big, red and shiny. Initially I planned to use it to deploy new versions of websites to a server but I found a much better use: ordering pizza. Graphically the use case translates to something akin to:

If you would like to enhance your life quality leveraging the power of a USB pizza-button: you can! This is what you need:

1. A PC running Linux. This tutorial is specifically geared towards Debian-based distos. YMMV.
2. A big, shiny red USB button. Just google “USB panic button” if you want one.
3. A location where you can order pizzas via a website. I live in Ghent, Belgium and use just-eat.be. Other websites can be supported by modifying a Ruby script.

Technically we need a driver to check when the button was pushed, a way to communicate the fact that the button was pushed and lastly we need to be able to react to the request.

The driver: on the internets I found a driver for the button. Another modification was done to make the driver process a daemon.

The communication: The original Python script executed another script on the local pc. A more flexible approach is possible using sockets. With sockets it is possible to notify any computer on a network.

  
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if PanicButton().pressed():
  # create a TCP socket
  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  # connect to server on the port
  s.connect((SERVER, SERVER_TCP_PORT))
  # send the order (margherita at restaurant mario)
  s.send("mario:  [margherita_big]\n")

The reaction: a ruby TCP server waits for message from the driver. When it does it automates a HTTP session on a website. It executes a series of HTTP-GET’s and POST’s. It uses the mechanize library.

  
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login_url = "http://www.just-eat.be/pages/member/login.aspx"
a = WWW::Mechanize.new
a.get(login_url) do |login_page|   
  #post login_form
  login_form = login_page.forms.first
  login_form.txtUser = "username"
  login_form.txtPass  = "password"
  a.submit(login_form, login_form.buttons[1])
end

Some libraries are needed. For python you need the usb library, the python deamons lib needs to be installed seperatly. Setuptools are needed to install the deamons package.

  


  
sudo apt-get install python-usb python-setuptools

Ruby needs rubygems to install the needed mechanize and daemons library. Mechanize needs the libxslt-dev package. You also need the build-essential package to build mechanize.

  
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sudo apt-get install rubygems libxslt-dev
sudo gem install mechanize daemons

To automatically start the daemons on boot you can use the crontab @reboot directive of the root user. E.g.:

  
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@reboot /opt/pizza_service/pizza_daemon.rb
@reboot /opt/pizza_service/pizza_button_driver.py

Code, Poging tot humor, Projecten, en Hackerspace Ghent

order_pizza_with_panic_button.jpg, pizza_daemon.rb.txt, pizza_server.rb, usb-panic-button.png, en pizza_button_driver.py

~ Touchatag RFID reader and Ubuntu Linux

This blog post is about how to use the Touchatag RFID reader hardware on Ubuntu Linux without using the Touchatag web service.

An RFID reader with tags can used to fire events. With a bit of scripting the events can be handled to do practically any task.

Normally a Touchatag reader is used together with the Touchatag web service but for some RFID applications the web service is just not practical. E.g. for embedded Linux devices without an Internet connection. In this tutorial I wil document how I got the Touchatag hardware working under Ubuntu Linux.

To follow this tutorial you will need:

• Touchatag hardware: the USB reader and some tags
• A Ubuntu Linux computer (I tested 9.10 Karmic Koala and 8.04 )
• SVN to download source code from a repository

The touchatag USB reader works at 13.56MHz (High Frequency RFID) and has a readout distance of about 4 cm (1.5 inch) when used with the touchatag RFID tags. Internally it uses an ACS ACR122U reader with a SAM card. A Linux driver is readily available so when you plug it in lsusb you should get something like this:

  
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lsusb 

Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 004: ID 072e:90dd Advanced Card Systems, Ltd

lsusb recognizes the device incorrectly but that’s not a problem. To read RFID-tags and respond to events additional software is needed: tagEventor is a software library that does just that. It can be downloaded using an svn command:

  


  
svn export http://tageventor.googlecode.com svn/trunk/ tageventor

To compile tagEventor a couple of other software packages or header files should be available on your system. Te tagEventor software dependencies are described on the tagEventor wiki. On Ubuntu (and possibly other Debian based distro’s the installation is simple:

  
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sudo aptitude install build-essential libpcsclite-dev build-essential pcscd libccid
#if you need gnome support
#sudo aptitude install libgtk2.0-dev

Now the tricky part. Two header files of the pcsclite package need to be modified (update: this bug is fixed see here). tagEventor builds and can be installed:

  
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cd tageventor
make
...
tagEventor BUILT (./bin/Release/tagEventor)

sudo ./install.sh
...

When tagEventor is correctly installed the only thing left is … to build your application. When an event is fired tagEventor executes the /etc/tageventor/generic script with three parameters (see below). Using some kind of IPC an application can react to events. A simple and flexible way to propagate events (inter-processes, over a network, platform and programming language independent) uses sockets. The code below is the /etc/tageventor/generic script (make sure it is executable), it communicates with the server: the second script. To run the server execute ruby /name/of/server.rb

  
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#!/usr/bin/ruby

# $1 = SAM (unique ID of the SAM chip in the smart card reader if exists, "NoSAM" otherwise
# $2 = UID (unique ID of the tag, as later we may use wildcard naming)
# $3 = Event Type (IN for new tag placed on reader, OUT for tag removed from reader)

require 'socket'

data = ARGV.join('|')
puts data

streamSock = TCPSocket.new( "127.0.0.1", 20000 )
streamSock.send(data, 0)
streamSock.close

  
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require "socket"  
dts = TCPServer.new('localhost', 20000) 
loop do  
   Thread.start(dts.accept) do |s|
     puts s.gets
     s.close  
   end  
end

The tagEventor software is made by the Autelic Association a Non-Profit association dedicated to making technology easier to use for all. I would like to thank Andrew Mackenzie, the founder and president of the association for creating the software and the support.

Touchatag hardware

Code, Harde waren, en Projecten

~ Jobsopschool

Ik heb in opdracht van scholengroep Sperregem een website gemaakt die het vinden van kandidaten voor korte vervangingen vlotter doet verlopen. Mensen met interesse voor een job in het onderwijs in de omgeving van Torhout, Kortrijk, Zedelgem kunnen zich er op inschrijven.

De website heeft enkele voordelen voor verschillende scholen in de scholengroep:

• Het zoeken van kandidaten is erg eenvoudig: na het invoeren van een vacature komt er een lijst met kandidaten met een geschikt profiel die tijdens de vacature beschikbaar zijn.
• Er kunnen e-mail of SMS-berichten verstuurd worden om kandidaten op de hoogte te brengen van een vacature.
• Profielen van kandidaten zijn altijd up-to-date: de kandidaten zijn er zelf verantwoordelijk voor en kandidaten lange tijd niets van zich laten horen worden automatisch op non-actief gezet.
• De historiek van kandidaten wordt automatisch bijgehouden en kan opgezocht worden.

Ook voor de aspirant onderwijzers is de website handig:

• De vacatures zijn publiek zichtbaar, kandidaten kunnen dus actief solliciteren.
• Ze kunnen zelf hun profiel beheren en bijvoorbeeld een vernieuwde versie van hun C.V. uploaden.
• Voor elke kandidaat is een gepersonaliseerde lijst met vacatures beschikbaar (ook via RSS), afgestemd op hun profiel.

Daarnaast is het ook voor de personeelsdienst een handige tool: die kan nu een beter overzicht bewaren over de vacatures en de invulling ervan in de verschillende scholen.

Hieronder staan enkele screenshots.

Startpagina

Nieuwe vacature

Code, Projecten, en Portfolio

~ Vooruit.be vernieuwd

Vandaag is de vernieuwde vooruitwebsite gelanceerd:

We bieden je nog meer video’s, foto’s, audiotracks en tekstmateriaal en hebben ook jouw persoonlijke voordelen uitgebreid. Wanneer je lid wordt van www.vooruit.be, kan je nog steeds je kalender aanvullen, vrienden maken en reacties posten, maar daarnaast krijg je ook aanbevelingen op maat, kan je voorstellingen tippen en kan je berichten sturen naar vrienden *.

Het gepersonaliseerde aanbevelingssysteem is door Greet Dolvelde en mezelf in het kader van onze thesis: Collaborative Filtering: Onderzoek & implementatie [pdf] ontwikkeld. Dus waar wacht je nog op? Word lid, check de aanbevelingen bij concerten en vooral je gepersonaliseerde aanbevelingen.

Voor de iets minder enthousiaste doorklikkikkers staan hieronder wat screenshots van de verschillende soorten aanbevelingen op www.vooruit.be:

Gebruikersprofielpagina

Aanbevolen evenementen

Buren

Aanbevolen artiesten

Evenementpagina

Aanbevelingen bij evenement

Gelijkaardigheid tussen gebruikers

Code, Cultuur, en Vooruit