On a lazy Sunday afternoon, some time back now. I decided to build a synthesizer.

Analogue electronics is not really my thing, I’m much more a digital person but when I found a design online for The #3 Standard WoggleBug by Grant Richter, I just had to build one.

First I built the circuit on some veroboard. This thing is controlled by a bunch of potentiometers, there is no keyboard and certainly no MIDI!

Then I was wondering what to make for an enclosure. My friend Jasper found an empty CD spindle and you know, it was just crazy enough to work.

To create the control panel, I got a CD-R and messed it up a bit with a blowtorch. I mounted the knobs on this and glued it to the central shaft of the CD spindle. A little more glue and the whole thing was assembled inside the spindle.

Here is the finished product. As you can see, the cover of the CD spindle makes a handy travel case.

If you want to hear what it sounds like, Click here for an MP3 (1MB). Okay, this is not a pure recording, I have added some drums and a couple of effects because this thing sounds really rough and is almost impossible to control. You’ll have to imagine me twisting the knobs frantically while you listen.

Anyway, I had fun building it and that’s what makes me happy.

Today I have an interesting problem, a customer in Melbourne has some issues with their Linux box and I would like to log in and fix them. The only problem is, their machine is behind a firewall and NATed to a 192.168.0.x address. The obvious solution would be to use port-forwarding on the firewall but that would involve a lengthy argument with their IT department so here is another way to do it using an SSH reverse tunnel.

This technique requires the cooperation of the customer which is good in a way because they get to control when I have access.

I should note at this point that this technique is based on the one mentioned here on the Gentoo forum.

First I set up a non-privileged account on my linux server which has a public IP address. Then I email this little script to the customer:

#!/bin/sh
ssh -R 10000:localhost:22 doofus@doctort.org

Once they have placed the script on their server and run it (they also need to type the password for the doofus account), I can log into their machine by typing this: (I need to know the root password for their box of course)

ssh root@doctort.org -p 10000

This will actually log in as root on their box. SSH is wonderful don’t you think ?

UPDATE 31-May-2007

I recently had to do this on a server running Debian Etch. In Etch, the tunnelling feature is turned off by default thus preventing this technique from working. To enable tunnelling, you need to edit the file /etc/ssh/ssh_config and add the following line:

   Tunnel yes

Then you need to restart the ssh daemon by typing this:

/etc/init.d/ssh restart

I’m writing this down because I always forget how to do it. Usually your window manager would take care of this for you but here in the embedded Linux world, we don’t always use a window manager.

There’s a lot of detailed information here but in a nutshell, put the following code into the Monitor section of /etc/X11/xorg.conf

        Option          "DPMS"

and then, put this in the ServerLayout section:

        Option          "BlankTime"     "0"
        Option          "StandbyTime"   "0"
        Option          "SuspendTime"   "0"
        Option          "OffTime"       "0"

PS. I could have used the “NODPMS” option but this way leaves it open in future to set some screen blanking timeouts if I so desire.

These are my notes on setting up the IVTV driver on an Ubuntu system. The documentation at the IVTV web site is excellent but what I really want is a simple step-by-step specific to Ubuntu so here we go (this will probably also work on Debian).

Go to http://ivtvdriver.org/ and download the source code appropriate for your kernel version (eg, I have kernel 2.6.15 so I download version 0.4.6). Also download the firmware from the firmware page.

You will need to install the kernel-headers for your kernel:

$ sudo apt-get install linux-headers-`uname -r`

Compile and install the driver:

$ tar zxvf ivtv-0.4.6.tar.gz

$ cd ivtv-0.4.6/

$ make

$ sudo make install

Then unpack the firmware:

$ cd /lib/firmware/`uname -r`

$ sudo tar zxvf ~/firmware.tar.gz

Finally, start the driver:

$ sudo modprobe ivtv

If all goes well, you should be able to see positive looking messages in your dmesg. You can test the video capture is working by issuing the comand

hexdump -C /dev/video0 | head

- you should see a few lines of hex codes. If it doesn’t work, well this is just a simple step-by-step so you will have to work it out for yourself.

Kai has his own web page now. Check it out at http://www.20-20.org/kai

The designers of this DVD player have stepped over the line with this one! What will be next, an “RTFM” button ?

Who says you don’t get wildlife in the city. This friendly fellow was waiting on my bathroom window to greet me as I was having my shower this morning.

Update: I replaced the original photo (taken on my phone camera) with this much nicer one taken by Bea and her fancy camera.

PS. The spider is on the other side of the glass or Bea would not be putting her finger this close.