GuruBlog : Articles about python

Arduino based Office-WTF-Counter

2009-07-03T08:37:00+02:00

As in any office, my co-workers and I experience several WTF-Situations during our working day. So we decided to implement a simple system to count the WTF's and use them as a metric for our working climate :-)

we use an "emergency stop"-Button which is connected to an arduino. This arduino sends the string "WTF" on the serial line a little python scrip writes them to a file, another processing app count's the lines in the file and offers the result via http, which is read by a processing app for visualisation ...

rotated text in reportlabs

2009-04-09T10:09:00+02:00

if you want to make a great chart like the one below in reportlab, you need rotated text. it isn't very complicated - its just a bit hard to find som examples on the net.

the canvas in reportlab has a saveState and a restoreState method, and supports rotate and translate similar to openGL or processing. see the code example below who it is done.

using the BlenderGameEngine as OSC client

2009-03-08T15:18:00+01:00

i just managed to use the GameEngine of blender as a client for OSC events :-)

now i can change the color of a cube by sending osc events from my pd-patch or the ruby-script i wrote for my openframeworks-demo

the blend file can be downloaded here

the blend file needs OSC.py by Daniel W. Holth to be in the python searchpath, so either copy it to location you start blender form or copy it to your site-package folder (obviously i'm not the only one who had the idea of using this lib with the blender game engine :-] )

very simple OSC debug tool

2009-03-06T08:09:00+01:00

when playing with OSC and i'm not quite sure what osc messages get send by an application i use a little python script which uses the simple OSC api

import osc
osc.init()
osc.listen( "127.0.0.1", 1234 )

in fact it misuses the library ;-)

every time a message is received that isn't bound by a callback function (which is all messages, since we dont bind anything here ), the listener prints a waring containing the address, the format and the value of the message

What's new in Python 3.0

2009-02-09T18:48:00+01:00

i have played a bit with python3.0 and this are the things that catched my eye:

the new print syntax
the exception-handling
decorators
the new io module
classes in python

are no complete list of changes between 2.5 and 3.0 - and don't want to be. they are just a list of thing's i noticed. Some of them are already present in python 2.6 but i newver used that release - so i don't realy know.

flying with python3.0

2009-01-16T18:48:00+01:00

I recently installed python3. While scanning through the module directory a package named "antigravity" catched my eye.

when i typed "import antigravity" python opend a browser-window with this link

i really like python - and xkcd :-)

Disco

2008-09-22T07:45:00+02:00

I recently read about disco a implementation of the map-reduce algorithm using erlang for the master node and the workload management and python for the map-reduce jobs. Its realy funny that the nokia research labs implemented an algorithm introduced by google using a language developed by erricsson :-)

its a bit complicated to install, but once running its realy fun to code with

ReportLab Test

2008-09-10T09:03:00+02:00

I just have tested reportlab a python-framework for pdf generation.

from reportlab.pdfgen import canvas
from reportlab.lib.units import cm


c = canvas.Canvas("hello.pdf")

c.drawString(2*cm,28*cm,"Hello World")

c.line( 2*cm, 26*cm, 2*cm, 16*cm)
c.line( 2*cm, 16*cm, 12*cm, 16*cm )

c.setFillColorRGB( 0, 0, 1 )
c.rect( 2.5*cm, 16*cm, 1.5*cm, 7*cm, fill = 1 )
c.setFillColorRGB( 0, 1, 0 )
c.rect( 4.5*cm, 16*cm, 1.5*cm, 6*cm, fill = 1 )
c.setFillColorRGB( 1, 0, 0 )
c.rect( 6.5*cm, 16*cm, 1.5*cm, 8*cm, fill = 1 )

c.showPage()
c.save()

this little script generates a pdf containing 'hello world' and a simple bar-chart. i think i will give it a try if i have to generate pdf-reports the next time

Multicard setup with freevo

2008-01-15T07:07:00+01:00

I'm using freevo for my vdr and like it very much. Recently in austria terestrial analog tv has bin turned off and everyone had to switch to DVB. So our block got a big Satelite-Receiver and a box that transcodes the DBV-S signal to DBV-C. and i hat to put a DVB-C card in my freevo box ...

to "make the hunt more interessting (shirkan - the jungle-book)" some of the channels still come over analog-tv. freevo handles mulit-card setups very well, but only if the cards are the same type. So i had to patch it a little to support my setup where some channels have to be recorded and viewed from one card and some from the other.

i extended the 'VideoGroup' class by a "vcr_cmd" member, and wrote a little record-pluin that sets the command depending on the channel description

VIDEO_GROUPS = [
    VideoGroup(vdev='/dev/video0',
            adev=None,
            input_type='tuner',
            input_num=0,
            tuner_norm='pal',
            tuner_chanlist='europe-west',
            desc='Default Video Group',
            group_type='ivtv',
            record_group=None,
            vcr_cmd='/usr/local/bin/ivtv-record.py %(filename)s %(channel)s %(seconds)s',
      ),
    VideoGroup(
            vdev='/dev/video0',
            adev=None,
            input_type='tuner',
            input_num=0,
            desc='DVB Viewer',
            group_type='dvb',
            record_group=None,
            vcr_cmd = 'mencoder -oac copy -ovc copy -o %(filename)s -dvbin card=1
                            "dvb://%(channel)s" -endpos %(seconds)s'
      )
    ]

ivtv-record is a small script i have written because i cant use the ivtv plugin anymore (it doesnt use the cmd variables). my record-plugin is a extenion to the "generic-record.py" where i changed the line 'self.rec_command = config.VCR_CMD % cl_options' to 'self.rec_command = vg.vcr_cmd % cl_options'