GeekSanta writeup

A surprisingly successful set of workshops were run over the last month, on soap-making, useless machines, and knitting decorations for christmas trees from chainmail. The useless machines workshop was run by Martin and was very successful. Those who missed out on buying a kit on the day may buy direct from him on his website.  For those who don’t know what a useless machine is, participant ntoll wrote it up, including a video.

The soap-making workshop started with some serious demonstrations of melt and pour soap and how to add dyes and pigments, but got very rapidly experimental.  Unfortunately there are no picture’s of Mat’s mustard-dyed “soap”, which is probably all for the better.

Pat ran the chainmail workshop, and taught how to make simple European 4-in-1 and European 6-in-1 with coloured rings to make trees.  This went well and the chainmail forest is shown below.

On the success of these workshops, we shall definitely organise more, although not quite so many together.  Any suggestions for workshops to be made via comments, Twitter, Facebook, the mailing list.  And roll on GeekSanta 2013!


Christmas meal 2012

We’re going to have a Christmas curry this year, on the 10th December.  The current plan is meet in the Malt Shovel on Bridge Street at 7pm onwards, and then move to Aladdin’s Balti Hut for 7.30pm.  Comment on the mailing list if you’re coming so I can book the table

SDR flowchart: POCSAG

Not sure any of these are entirely working, but the local area doesn’t appear to use POCSAG but has maybe gone onto FLEX as the frequency bands look a bit busy.

Simplest attempt is using a modified version of osmo-pocsag.  It writes out baseband to a file.  Create a fifo, and direct the the cmdline app to its output.
A more complex version is based on this (by bafe), and has some good waterfall pictures to give a better indication of what’s going on.  Confusingly it’s called gr-pocsag, and thus confusable with the POCSAG decoding GRC block by patchvonbraun here, which needs compiling and installing.
I’ll update this once I’ve actually either confirmed that what I’m seeing is not POCSAG or which/either/both/none works.

Playing with the RTL SDR

So the hackerspace will imminently have a number of Realtek-based SDRs as demonstrated last meeting.  An SDR, or Software-Defined Radio is a very flexible device, that performs the equivalent of a “raw recording” of a portion of the RF spectrum and then the raw samples can be processed in any way you like on your computer.

So for example, you can pick up FM radio, the pager network, transmissions from the ISS, or aircraft transponders.  Working GRCs will be posted on the blog
We’re going to try doing some of these things in the space over the next few months, the exact dates will be discussed on the list.  If you’d like to try this, here’s some links:

Another useful resource is the subreddit for it.