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Current state of the art

Hello and welcome to my dev blog!
So this blog is to track what I am up to in my developing...

I am a python convert - when ever I can I now use python.
At this very moment I am working as an engineering intern for Tait Electronics. My research project here is "Using Python as a replacement to Matlab in the field of signal processing".
To this end I am using scipy and matplotlib daily. I have a iBook G4 (ppc) and run linux - precompiled binaries for closed source apps like skype and adobe flash simply don't get realeased for the powerpc. This makes life far more interesting!

Work environment
  • Windows 2000 - eek

  • Eclipse (Version: 3.4.1)
    • Pydev (1.4)
    • Pydev Extensions
    • svn
    • mylyn

  • Enthought Python Distribution (Py 2.5 + scipy + numpy + matplotlib)
  • Python 2.3 -> 3.0 (and svn trunk)

Home environment

  • Ubuntu 8.10 (ppc)
  • Eclipse
    • Pydev
    • svn
    • mylyn
  • django (svn)
  • django-command-extensions (svn)
  • Python 2.5, 2.6, 3.0
  • scipy, numpy and matplotlib, pil...
  • gammu, python-gammu (No wammu - due to Segfault on startup)
  • Sony Ericson 880i + usb cable
  • MythTV/ftp/trac/svn/ssh server


Not open source (at this stage) This project involves making a sms server for interacting with an alarm via txt messages or web interface. Making heavy use of python-gammu for the phone side of it, and django for the web side.


What does it do? Tidy up all your tv episodes. Rename and move your files in the way and location of your choice. Downloads episode names from imdb and renames them in the format you specify all from a cross platform native looking gui. Easily extended and editable to support other tv shows. Eptidy supports proxy setting
Project Page:


Someone emails This program reads the "to" address of the incoming email and searches through your sites members for anyone matching "some name", then looks up the email address of that user. It resends the email, from the original sender to the actual email address looked up. If the user wasn't found it optionally looks through a jobs database then at groups. If still not found the mail is returned to sender with a user not found error.
Project Page:

University of Canterbury Canoe Club Webpage
Custom php framework driven site... currently getting redesigned and one day I will redo in a real language...
Old version of the Code is online at my misc repo for all my shared uni code.

Bev's Tramping Gear Hire and Ana's Place Websites
Ditto - same framework...
Tramping Information and Gear Hire:
Ana's Bed and Breakfast Te Anau:

Usually have a few small projects for the flat server as well

Getting a multi project trac install was the last thing I did. We have ordered new parts and are probably going to do a fresh server install of ubuntu tho, so not entirely sure about going through that again! Although it is very nice to have when its up!

Voipstunt - One of the more recent ones was making a script that logs into voipstunts free calling homeline to homeline. So we could go to the flat website and enter in a phone number and then our phone would ring as voipstunt connects us to the number we dialed...

Future Things
A future project will be going from ubuntu to gentoo on my ppc because to many things are broken in the repository at the moment. Ekiga didn't work untill I compiled from source. Wx programs in general seem to fail. Filezilla flashes onto the screen before dieing a miserable death...
Want to have a good play with ompc.
A media manager for keeping track of what episodes you are up to in a series... in the very early stages of development for that...
I want to get django going on my current webhost:

That should just about do it for now!


Popular posts from this blog

Matplotlib in Django

The official django tutorial is very good, it stops short of displaying
data with matplotlib - which could be very handy for dsp or automated
testing. This is an extension to the tutorial. So first you must do the
official tutorial!
Complete the tutorial (as of writing this up to part 4).

Adding an image to a view

To start with we will take a static image from the hard drive and
display it on the polls index page.
Usually if it really is a static image this would be managed by the
webserver eg apache. For introduction purposes we will get django to
serve the static image. To do this we first need to change the

Change the template
At the moment poll_list.html probably looks something like this:

<h1>Django test app - Polls</h1> {% if object_list %} <ul> {% for object in object_list %} <li><a href="/polls/{{}}">{{ object.question }}</a></li> {% endfor %} </ul> {% else %} <p>No polls are available.</p> …

Homomorphic encryption using RSA

I recently had cause to briefly look into Homomorphic Encryption, the process of carrying out computations on encrypted data. This technique allows for privacy preserving computation. Fully homomorphic encryption (FHE) allows both addition and multiplication, but is (currently) impractically slow.

Partially homomorphic encryption just has to meet one of these criteria and can be much more efficient.
An unintended, but well-known, malleability in the common RSA algorithm means that the multiplication of ciphertexts is equal to the multiplication of the original messages. So unpadded RSA is a partially homomorphic encryption system.

RSA is beautiful in how simple it is. See wikipedia to see how to generate the public (e, m) and private keys (d, m).

Given a message x it is encrypted with the public keys it to get the ciphertext C(x)with:

To decrypt a ciphertext

Bluetooth with Python 3.3

Since about version 3.3 Python supports Bluetooth sockets natively. To put this to the test I got hold of an iRacer from sparkfun. To send to New Zealand the cost was $60. The toy has an on-board Bluetooth radio that supports the RFCOMM transport protocol.

The drive protocol is dead easy, you send single byte instructions when a direction or speed change is required. The bytes are broken into two nibbles: 0xXY where X is the direction and Y is the speed. For example the byte 0x16 means forwards at mid-speed. I was surprised to note the car continues carrying out the last given demand!

I let pairing get dealt with by the operating system. The code to create a Car object that is drivable over Bluetooth is very straight forward in pure Python: