I googled around but weren’t able to find such a utility. But i did find cli-sip client pjsua, based on pjsip. Its posible to use it in conjunction with a shell script.

Scripting

jacob@vps:~./control.sh sip:108329@foobar.com "wake up you lazy bastard!"
Is the basic usage i wanted to have. In order to get this functionality there are two steps.

Generating wav file

I ust use text2wave, from festival, which is available as a package on ubuntu.
echo $2 | text2wave - -o message.wav

$2 to use the second argument, and pipe it to text2wave. Let text2wave read sdtin and output a file message.wav

Call and play the wav file

pjsua_app --config-file=test.conf --play-file message.wav $1
Here the magic is in the conf file. Its a rather straightforward to use, and the documentation is good.

# we don't want the host's audio device
--null-audio
# SIP parameters
--realm domain.com
--registrar sip:number@domain.dk # DNS SRV, or FQDN
--username USERNAME
--password PASS
# default of 55 will be rejected as being too short by sipX
--reg-timeout 3600
# auto-answer all calls with "200 OK"
--auto-answer 200
# automatically loop incoming RTP to outgoing RTP
--auto-loop
# mix WAV file into the audio stream
--auto-play
--auto-loop
--duration=60

This is based on a config file i found somewhere, can’t remember where. There a a lot of other options, pjsua handles nat quite nicely as well. It was easy to test it at my homebox, behind a router, just be sure to set an external ip address.

Now this will call and play the message, but it wont stop pjsua. It will just sit around waiting for someone to call. I couldn’t find any nice way to handle this, but since pjsua reads stdin for commands, it possible to pipe commands to it.
echo "sleep 60000 q" | pjsua_app --config-file=test.conf --play-file message.wav $1
So sleep for 60 seconds, then accept the next input from stdin, the “q”uit command.

Generally this configuration is set for 1 minute, it might be necessary to tweak this.

Frustrations

There is/were a bug in the tarball, that meant that it wouldn’t run if it couldn’t find a soundcard, since it should run on a vps this is quite annoying. But in the svn version its solved, so if you want to do something like this, use the svn version. Other than this installation is straightforward.

When working with cron, remember to use full paths. In the control.sh script the better solution were to add a cd working directory, in order to have all the paths correct. This were quite annoying to debug, as the script would run from the shell. And just fail when added to the crontab. Furthermore mails from crontab were delayed, so i couldn’t see the output. I did get someone to look over my shoulder and spot the bug.

I made have generated quite some random attractors.

Now I need to find the most beautiful ones, and I need your help!

I have created a voting system, where 3 attractors line up and you select the best one. The votes are then accumulated and and overall top 10 is generated.

Strange Attractor wars

It is heavily inspired by kittenwars.com.

I have been hacking away on this far to long. But expect an article with more details on Strange attractors and probably more features in the “war” application. (like top 100, biggest looser, most victorious etc).

Now just go and make some votes

But they are not as fascinating as CA’s where you expand the neighborhood to include all the eight adjacent cells. That’s called the Moore Neighborhood.

Representing the time dimension. As the intersting part is the evolution of the system, representing time is essential. With a two-dimensional CA it has to be done using animations, and who doesn’t like blinking pixels. This makes CA’s makes even more fun.

In order to decide the state of a cell I look at the Moore neighborhood for every cell on the grid, and count how many neighboring cells are alive. If a cell is alive, then we have to determine whether it survives or dies. If a cell is dead / empty there is the posibility of birth. By defining how many neighbors a cell has to have to survive, and hov many it takes to “give birth” it is possible to run the automata. And this is enough to define a highly complex behavior.

The ubiquitous Conway’s game of life survives if there are 2 or 3 neighbor’s alive and a cell is born if 2 cells are alive, this can be written as : S/B = 23/2. Using a notation like this makes it easy to try out new rules, just adjusting the S/B sets.

I made a small c++ program again using CImg to render these automatons. It’s a rather quick hack, and as such there are plenty off room for optimizing.

But for now it does its job and I don’t intend to develop it further, at least for now. And I think that CIimg might not be the best api for this, I need to look into SDL.

I spent way too much time hacking around to get a nice coloring scheme, and well CImgs intended users are making image manipulation, and not generating images from scratch. SDL is’t intended to generate images from scratch either, but as far as i can tell its easier to manipulate images as int arrays.

Well it does work and i were able to try out some of the rules listed at Wikipedia article about Life like cellular automatons, there online java simulators somewhere on the Internets so I won’t bother to upload any videos – as its much more fun to watch in action an play about with the settings as you go along. If you want to play with the code, well here it is : Cellular Automaton code it’s ugly and you need CImg.h

And now I’ve just downloaded EvoCell which has all the features and a lot more.

Online simulator : MJcell this is a very good implementation. Its fast and has lots of rules and patterns