OSDC 2010 - First Draft Program

The programme is up! Tentative, but up! http://2010.osdc.com.au/programme

Web Cams for Linux

So as a result of a friend asking me about web cam support under Linux for a computer vision project, I found some interesting resources that I thought was worth sharing.

The Linux UVC driver and tools web site lists a couple of really cheap web cams like the Logitech Quickcam C150, which we can source locally for $18 at MSY.

So, some solid state storage, a usb hub and a tiny home server or decent wifi accesspoint with usb would be ideal for this project =)

73, Kim

Interesting power generation projects from the crew of HackerSpace Adelaide

Paul, VK5FPAW, after a challenge from the Adelaide HackerSpace crew, has bee putting together a pedal power rig to power his HAM radio rig for the WIA WIA National Field Day on the October 23rd. Perhaps other HAM radio contents too, like the WIA Spring VHF-UHF Field Day is on November 20th & 21st. More events on the WIA Calendar.

Over at; http://picasaweb.google.com/pschulz01/PedalPower, Paul has a few photos of his pedal power rig. The stationary trainer is a nice way to mount everything. The alternator is a 50A Bosch. So far Paul has spent about $250.

I'm looking forward to hearing Paul, VK5FPAW/StationaryMobile on air on the field day ;)

73, Kim

New warning system for solar storms

From the WIA broadcast news this morning;

WIRELESS WEATHER

NEW EUROPEAN SYSTEM GIVES WARNING OF SOLAR STORMS

Researchers at the University of Bradford located in the United Kingdom say that a new method of predicting solar storms that could help to avoid widespread power and communications blackouts has been launched. Amateur Radio Newslines Norm Seeley, KI7UP, says that up to now, solar weather prediction has been done manually with experts looking at 2 dimensional satellite images of the sun and assessing the likelihood of future activity.

But a team from the university's Centre for Visual Computing has created the first online automated prediction system using 3D images generated from the Solar and Heliospheric Observatory or SOHO satellite.

Already in use by both NASA and the European Space Agency, the Bradford Automated Solar Activity Prediction system also known by the acronym ASAP identifies and classifies sun spots and then feeds this information through a model which can predict the likelihood of solar flares. The system is able to accurately predict a solar flare six hours in advance and the team is working to achieve a similar accuracy for the prediction of major solar eruptions in the near future.

Solar storms involve the release of huge amounts of hot gas and magnetic forces from the surface of the sun into space at around a million miles an hour. The next major solar storms are expected in 2012-13 as part of the sun's 11-year weather cycle. A 2008 US National Academy of Sciences report estimated that modern reliance on electronics and satellite communications means a major storm could cause twenty times more economic damage than Hurricane Katrina.

Although major solar eruptions and coronal mass ejections normally take several days to reach the Earth, the largest recorded in 1859 took only eighteen hours. Solar flares which can also cause significant disruption to communications systems take just a few minutes. Because of this, advance warning is of vital importance to enable steps to be taken to avoid the worst effects of such solar activity.

Data recovered from the system is on-line at the European Spaceweather website;

http://www.esa-spaceweather.net/sda/asap/

The VK5 News: 3rd October

AHARS
Saturday, 23rd October; National Field Day @ Eden Hills Primary School, Strawberry Fair
VK100WIA
Sunday, 7th November; AHARS buy and sell
2nd, 4th Friday; Lunch Blackwood RSL
JOTA 16th
More at; http://www.qsl.net/vk5bar/
VK5KC David

WICEN
9,10th foundation license
23rd October, Nat Field Day
20th, 21st November foundation license training
QRP CW @ Rostrevour Tennis Club
More at; http://www.sa.wicen.org.au/
VK5PH Paul

AREG
Friday 15th October; Meeting at the Reedbeds; Talk on coax cable, types, suitability, tools included
More at; http://www.areg.org.au
VK5BB Ben

Back to studying

Well its been a while since I've regularly had a toasty soldering iron on the workbench. Well for that matter its been a while since I've had a workbench. I have a bench in the shed, but its been so cold and wet that it is really not any fun spending any time there. Also there have been some house renovations that have made space an issue, to the point that I boxed up a bunch of books. I put them "somewhere".

So last weekend I dug out those "missing" books and flicked through looking for ideas. I have some work to do and need to brush up on a number of things. I downloaded the standard and advance syllabus as well so that I can tick off all the topics once I've covered them.

I also picked up a couple of Drew Diamonds books on the week end at the symposium; Radio Projects for the Amateur, volumes 3 & 4. I have been wanting to get my hands on these for some time. They were the first homebrew books I laid eyes on, on the WIA book store. However funds have been an issue for a while so they have been out of reach. Gladly no more is that a problem =)

I've made it through the scary bills part of the year and will be saving up for the "tome" of radio theory from the WIA, Radio Theory Handbook for Amateur Operators (5th ed.) by Fred Swainston, along with EMRFD.

How ever the cost of these seems to sky rocket every year and the postage is becoming outrageous! Oh well, heres hoping that I'll get the reading material before the end of year break to read during those lazy days of summer when work closes down for a bit... Mabye even get the chance to get away for a bit to unwind and read.

In the mean time, I want to read SolderSmoke the book again.

There were some rather crafty ideas presented in there that I need to get my head around again. Need more time on the workbench tinkering. Core things being to straighten out the mutual coupling/inductance and the whole transistor holes thing in my head =) Most the other ideas work for me. I need to tinker with the math around power calculations too. I kind of get it, but nothing backs it up like doing. I figured out current limiting resistors on the last read through =) Also can't wait for Bill to get another SolderSmoke podcast out. Its funny I miss that more than any other regular release HAM radio news. Would be great if it was monthly even. I keep thinking about putting together a podcast, but am still too shy of a microphone.

73,

Kim

Word of the day: flum

flum, v: to move or position an item on a quickly setting glue.

Yesterday I went along to the AHARS symposium. I had a wonderful time. The impact of the event probably won't be fully realised for some time yet. However, I took some notes and a few photos. Also will put together a couple of posts here about the symposium and ideas gleaned from it.

I like to write down words of phrases that I haven't heard before. 'flum' was one such word that I noted yesterday. Thank you to Drew Diamond, VK3XU, for extending my vocabulary. I have more notes to read through and plenty of googling to do =)

73,

Kim, VK5FNET

Exciting things at work

There is much cheer here at work at the moment. This is the season for the anual University rankings and we did pretty well.

Also this week, I am working on posting the videos of OpenDay Blog from last month. We also put them up on our vimeo channel.

We've been pretty busy for a while and next week we are interviewing for another programmer. So its a happy time here after lots of work leading up to OpenDay and other campaigns we've been working on.

73, Kim

junk code

Today I was tidying up my junk code directory. I cut this up one lunch time when I couldn't focus on the FTP server code I was bashing my head against - now sorted.

So, whats this for? There was a challenge a while back on the Brainwagon blog, using /dev/urandom to generate a list of 'random' characters to fit a pattern, ten blocks of five characters, each block separated by spaces.

This is used for testing cyphers and other fun stuff =) I spent some time when I was back in London working on some cypher and compression code. So I can vouch for the need for tools to generate large random sets - one time pads - that you can play back over and over to make sure that you reproduce that bug, with different versions of your code. Correctness was the issue at hand. Later came the performance issues.

So, Mark posted a "Unix/sh challenge". My brain needed a break and who can resist a bit lunch time shell coding? Well I tried and I got it pretty close. Anyway I decided to try a Perl version to see if I could make it easier to read, then make it faster.

#!/usr/bin/perl
my $limit = 10_000;
my @cypher;
while (<>) {
    my @chars = split(undef, $_);
    for my $char (@chars) {
        if ($char =~ m/[A-Z]/ ) {
          push @cypher, $char;
          if ($limit <= scalar(@cypher)) {
              my $offest = 0;
              while (@cypher) {
                  for (1..10) {
                      print "  ";
                      for (1..5) {
                          print pop @cypher;
                      }
                  }
                  print "\n";
              }
              exit;
            }
        }
    }
}

72, Kim

How small can you make antennae?

When we talk about "small antenna", I think about the homebrew antenna I have made for WiFi devices on 2.4GHz.

Now, you can make Yagis for any frequency right? Right, so have a look at this; Antenna directs light at the nanoscale.

"Niek van Hulst and colleagues at the Institute for Photonic Sciences in Barcelona ... fabricated a number of nanoscale Yagi Uda antennas containing the tiny parasitic elements made from gold using lithography to etch the devices onto a glass substrate. The total length of individual antennas was 830 nm where individual feeds were just 145 nm, each separated by 175 nm."

73, Kim

Quote of the day by SKR

I've been using this quote in my email for about seven or eight years;
"Art without engineering is dreaming; engineering without art is calculating." Previously I only had th initials; SKR

Today I found out that SKR is none other than Steven K. Roberts. Yes the creator of the Winnebiko and BEHEMOTH!

I started using that quote because it appealed to my inner geek. Especially after I saw a series illustrations from Janet Reid entitled; 'Renaissance Geek'

See the posts on the Make blog; Make it anywhere with a mobile lab;

• Part 1


• Part 2


• Part 3


• Part 3

AHARS Symposium September 19

Event; AHARS Symposium

Topics; Amateur radio, Construction

Speakers; Drew Diamond VK3XU, Phil Harman VK6APH and more

Venue; Belair Community Centre, Corner of Sheoak Road and Burnell Drive, Belair

Cost; $20 at the door for morning tea, lunch and afternoon tea.

Date; 19 September, 2010

Time; 930am - 5pm

Voltage dividers for 5volt Arduino and 3.3volt SPI devices

I am setting up a radio module to plug into an Arduino.
Specifically the RFM12B like in this schematic;
http://www.flickr.com/photos/jeelabs/3297526692/in/photostream/#/

The Arduino runs at 5volts and the RFM12B runs at 3.3volts. So I have to convert the line levels from 5v -> 3.3v on the inputs to the SPI device and from 3.3v -> 5v for the output.

The example has a 4K ohms and a 10K ohms resistor for the 5v to 3.3v voltage dividers for the Arduino output data lines into the RFM12B, does that sound reasonable?


I did the math and worked through the examples on the Arduino tutorial site and came up with the following values; 1.5K ohms, 2.2K ohms

72, Kim

usbsoftrock Ubuntu package, from the softrock40 group

Seeing the very lengthy instructions posted recently for how to install a set of SDR software for Ubuntu, I thought I'd make a (very small!) start on reducing that complexity.

This evening I've packaged the first piece of SDR-related software in that set of instructions, usbsoftrock version 1.0.1 , for Ubuntu Karmic, Lucid and Maverick. My initial "very unofficial" packages are (or will very soon be) available in my Ubuntu PPA for download and testing. As part of that process I created a (somewhat minimal) man page for usbsoftrock, so that lintian does not complain about the lack of such a page.

To use my PPA in Karmic, Lucid or Maverick, do:

sudo add-apt-repository ppa:jmarsden/ppa
sudo apt-get update

Then to install this packaged version of usbsoftrock, do:

sudo apt-get install usbsoftrock

and the correct version of the package for your release of Ubuntu (32bit or 64bit, Karmic 9.10, Lucid 10.04, or even Maverick 10.10 if you are running the Alpha version) will be installed for you. If I later update this package, you will automatically be made aware of the update, just as you are for other Ubuntu packages, and you will be able to automatically update it if you wish.

Graphically oriented Ubuntu users who prefer using Synaptic or a similar GUI package manager instead of the shell and apt-get can also add my PPA, and then use their package manager of choice to install usbsoftrock.

Note that this package is untested, because I do not possess any SDR hardware that would allow me to test it! Comments and feedback from those who *do* have such hardware are very welcome. Given sufficient interest, as time allows I will probably package up more SDR-related software for Ubuntu and Debian. Eventually such a set of SDR-related software packages could be added to the official Debian and Ubuntu software repositories, ready for easy installation by end users.

Questions arising:

(Q1) Is usbsoftrock usually used in daemon mode (with the -d option), or in command mode? Since it comes without any init scripts, I am assuming command mode is the usual approach, for now.

(Q2) The COPYING file in the source tarball is GPL-3, but the copyright statements in several of the included source files are "GPL-2 or later". Is there a reason for this? Could it be corrected so the two are consistent? This could help official acceptance into Ubuntu or Debian in future.

(Q3) The two source files interactive.c and interactive.h seem to lack any licence/copyright statement. If these could be added in the same manner as the other files are handled, that could also help official acceptance into Ubuntu or Debian in future.

(Q4) Is there an "official" online place from which the source tarball can be downloaded *without* needing to be a member of this Yahoo Group, and where new releases would appear? This would allow a "watch file" to be created in the package to check for new versions as they are released, etc. There is an automated monitoring system in place for this, but as far as I know it can't work with the files inside a Yahoo group file area, since the monitoring system (obviously) is not a member of all Yahoo groups.

(Q5) Currently my package allows access to the USB device(s) by any user in the 'admin' group. This probably works adequately for Ubuntu, but would probably work rather less well for Debian. Is there any standardization of a "hamradio" or similar group for these kinds of permissions which I should be using?

Lastly, if anyone else is packaging SDR-related software for Ubuntu or Debian, please let me know, so we can collaborate and avoid duplicating our efforts.

Thanks,

Jonathan
AF6YF