That doesn’t mean that i haven’t been coding small hacks, just that i haven’t posted them. But now is probably a good time to show some of the stuff.

As the title suggest it has something to do with processing.org. I have been using processing on and off for some time. Its is really nice when you want to make a quick hack, or as its called in processing a “sketch”.

In no particular order here is some of the fun stuff made using processing.

General remarks

The following sketches and their sourcecode have served as small hacks, hence don’t expect nice comments or optimal algorithms…

shrinkImage

It is possible to remove the line from a picture representing the least amount of information. The algorithm evaluates every pixels “weight” as the absolute difference between the different color channels (r,g,b). And then finds the “lightest path” from the bottom to the top.

This means that “prominent features” won’t be removed or change size when shrinking the image. Here the definition of “prominent features” is high difference in colors between the neighboring pixels.

Have a look at shrinkImage

Room for optimizations :

Eventhough its quite quick at calculating the weights and finding the lightest path, it does so in every iteration. Letting it use a bit more memory and just recalculate the changes when removing a line should speed it up. I found a huge speedup when just having an array with the weights from the last and current line, when calculation the path, so not only would saving all weights require a bit more memory it would also slow down the first calculation. But I’m sure it would give a significant speed up in the next iterations, and a lot of +-1 frustrations

helloFoo

There a some quick getting to know processing hacks, this is one off the. helloFoo

One of the very cool things about processing is the ability to use openGL, so originally this sketch uses openGL. But applets and openGL isn’t exactly the best combination. It can be done, but since it doesn’t work for me (firefox, linux openJDK JRE) i just converted it to standard java graphics. And the effort required to do this, is remove an import and don’t say setup(400,400, OPENGL) but just setup(400,400). This is trivially true the other way around. If you want to use openGL its quite easy.

The sketch is just bouncing balls, when going away from openGL I reduced the size and number of balls, in order to get a decent animation speed.

FooIII

Again used openGl originally FooIII

Some satellites rotating around some satellites rotating around some ….

sndHello

yes sketches tend to have silly names : sndHello

From Clifford Pickovers  book : Computers, Pattern, Chaos, and Beauty – graphics from an unseen world (p 39 section 4.3 snowflakes from   sound)
Draw symmetrically and in “polar form” the fft of the sound, hence creating snowflakes based on the sound.
Music by David Rovics
Choppy sound I had some problems with the sound when run as an applet. You might have better luck using the jar directly or by downloading the sourcecode and running it with processing

Slit-scanning

The former applet relied on an external library for the sound, ther are quite a few libraries available. I did use GSvideo to hook up my crappy webcam and do some video effects. I experimented with slit-scanning in different ways.Unfortunately this won’t run as an applet and it might only run on Linux.

By creating a cube of the images, where the z-axis represents time, its possible to play back different parts of the movie from different layers in time. Which makes for some quite interesting and dizzing effects.

For example a time buble where playback is delayed around a “bulge in the timespace continuum” :s (a video of some guy playing with it (timebuble1.avi) some sourcecode for a similar effect where the mouse pointer moves the buble (TimeCube.pde) another more “traditional slitscan” (CamWarpTime.pde) .

In general there is plenty of room to fiddle with the code, there a functions like selectSlice or initQueues where its decided how to slice time. its great fun to play with..

The very short desctiption :

inspiration from an example of homogeneous coordinates in my linear algebra book and lectures about lineartransforms.

There is a jar, with sourcecode, if you want to se it “live” or twiddle with it.

tegneri

I got around to hacking some code together for a simple DTMF dialer on the mobile.

Its functional and simple. Enter a number, click ok and it will play the correct sequence of tones. It’s even possible to tweak the duration and pauses.

I have only tested it on my own Nokia 6300, but as far as I can tell it should run on most java enabled mobile phones.

Here are the jad and jar files. If you want to run the program download them to your mobile and have fun.

• dtmf jad
• dtmf jar

At the moment it converts + to 00 and removes +45, as this is appropriate for a danish setting.

Here is the sourcecode if you need to make changes.

DTMF sourcecode

Using Netbeans

I used netbeans 6.0.1 and it was a mixed pleasure. Creating the the flow using a drag’n’drop interface, is well nice for something small and simple as this, but I found that it soon got frustrating. There’s no API to look in, and you have to use the mouse all the time.

This is the basic flow of the midlet. It was very quick to set this up, and it were indeed a pleasure to start with. Somewhere along the way a made a mistake, which the flowdesigner and codegenerator couldn’t handle. And no matter what I tried I couldn’t get rid of it, I knew exactly what i was. I had misnamed a variable and managed to let the generated code go into a never-ending recursion. (something along the lines of: private TextField foo() { return new TextField(Foo);} ). But no matter what I tried it just wouldn’t get back to normal. In the end I just created a new project, remade the flow stuff to what you see above, and copied a few functions over.

And the flowdesigner is quick to work with, but I get a nagging suspicion that if you are going to make something a little more complicated than this it will be an annoyance. You might know exactly where and what to change in the source code, but do you remember where to point, click and edit in the designerinterface? Another critique is that even when you know what to do, your workflow gets abruptted by having to constantly shift hands between keyboard and mouse.

To Netbeans defence i must say that I am used to using Eclipse, and changing to another IDE is in it self a frustrating experience. Whats the shortcut for blah, where do I set this. And its quite possible that I just didn’t know enough about Netbeans structure and shortcuts to feel at home.

Credit goes out to : openclipart.org for the image of the phone and dialabc for the soundfiles.

The first flash assignment were to create a picture slide show, with captions and a soundtrack. Using the Adobe flash gui its very easy, drag and drop “programming”.

But as Richard Stallman says “its not a matter of convenience, but of ethics”. So I went looking for replacements. In another course I had no problems using octave instead of matlab, so should this be any different? Yes, unfortunately it seems that its very difficult to get the needed features in free software, well at least in the given timeframe.

HaXe is able to compile to swf, as well as doing a lot of other nifty stuff. I just learnt about it recently from this video.

I didn’t manage to make the entire assignment, (yet?) in haxe, but i did make this :
flash presentation(5MB+)

UPDATE

I did manage to add sound and captions.

So how did I do it?

Well first of all i installed haxe and swfmill. Haxe is able to use the actionsscript api and swfmill can create resources so your are able to refference them in you haxe code.Here is the recipe i used to create this slideshow.

1. create a xml file for swfmill, in order to create a resources for the haxe code.This i something like

 <movie width="480" height="480" framerate="25">

   <frame>

      <library><clip id="img1" import="library/newton001Slide_.png"/>

unfortunately swfmill isn’t able to add sound to a library, so that had to be loaded directly from a file. I had some trouble getting it to function on the server but i think that adding “-D network-sandbox” to the haxe compilation might have done something. ???

2. run swfmill, thats swfmill simple slides.xml slides.swf

now i had linkage names for the image files, and could add them to the movieClip.

3. Create file SlideShow.hx

The main part. The basic haxe syntax is pretty straightforward, but since it uses the actionscript api it were mostly a question of getting a hang of actionscript. I did however strugle a bit with making a anonymous function, for the sounds onLoad. I used “static inline function sndStart(succes){…}” , its a wee bit diffrent than what i would do in java. but it works.

3. compile.

make a “make file” for haxe, compile.hxml

-swf test.swf

-main SlideShow

-swf-lib slides.swf

-swf-header 480:480:25:FFFFFF

-D network-sandbox

The last part -D is a conditional flag and as far as i can tell it shouldn’t do anything, but a saw it in Fmp3PlayerHx and when i added it the sound seemed to work from the server, using a URL :s :s

4. run haxe compile.hxml

5. display the pretty result. (try not to go crazy when wordpress decides to help you format the html code….), at first i tried embedding the flash in this post, but wordpress kept on changing the code, apparently if you add code and have newlines between the tags it throws in a couple og <p> tags …..

Now its on a separate page, then you don’t have to download the 5 mb flash file just to view the page, and I can use wordpress with out getting too frustrated.

sourcecode slideShow.hx

The music is “the free software song” this version is by Jono Bacon , and I personally prefer it to the version by Richard Stallman

So I started hacking away. Unfortunately I don’t have any nice video or sound clip, but then again its more like a noisemaker and its just a mess of wires. I’ll try to get something up soon.

But it does work, you have to take my word for it or download the sourcecode and wire up your arduino and try it out.

How does it work ?

There a two modes of operation “play mode” or “sequencing mode”, and it shift between modes by clicking the middelbutton (mousewheel button) and it starts out in sequence mode.

sequencing mode

• moving the mouse changes the frequency of the sound. It’s very simple the more you move, the more it changes (just by (X + Y) *magic_number)
• pressing the right mouse button reduces the duration of the sound
• pressing the left mouse button increases the duration
• turning the mousewheel selects a tone in the sequence, either an existing or adds a new one to the sequence.

play mode

• it plays the sequence of tones you’ve recorded.
• the mouse wheel changes the playback speed.

So it keeps track of both a duration and a frequency, it uses a queue and its possible to add sounds to both ends. I haven’t yet hit a maximum but since its in a int array my guess is that it should be able to hold a lot 100 or 1000 of tones. And it should be possible to do some bytepacking to reduce the memory requirements, but since you have to enter each sound manually and there are no persistent storage you really don’t need that to hold a lot of tones.

Sound Sequencing Mouse sourcecode

It was a matter of connecting 4 wires and uploading the code to get it running. But then i found out that there wasn’t support for the mouse-wheel, so i googled the datasheet for the IC, and started hacking. I ended up getting the mousewheel to function and getting output for the buttons. Along the way I refactored some of code, in order to better understand what was happening.

I still haven’t figured out what I should use the mouse for, but it was a fun hack.

Here is the sourcecode, if you want to try something with it : ps2mouse for arduino

I tried to make nice comments so it should be very straightforward to work with. As mentioned a haven’t made most of the code, just some additions and refactoring.

The mouse and the annoying encoder i couldn’t build a circuit for. It can be attached to a motor where there are a slotted wheel.

(21 nov updated code)

]]> http://rotand.dk/2007/11/21/arduino-ps2-mouse/feed/ 3 http://rotand.dk/2007/11/10/arduino-ambient-dashboard/ http://rotand.dk/2007/11/10/arduino-ambient-dashboard/#comments Sat, 10 Nov 2007 16:57:16 +0000 http://rotand.dk/blog/2007/11/10/arduino-ambient-dashboard/ Yesterday I finally got the Arduino, I ordered from Segor Electronics. Which by the way had a good service and packed it securely.

I had a plan to create a Ambient dashboard, that is to have some analog meters that would convey some digital information. In an non obtrusive way, i think it has a very fine name, peripheral awareness.

I found it easy to code the arduino and to work with, so far that is. Using ubuntu I for some peculiar reason had to uninstall braille support, as it automatically recognizes it a braille device.

In order to communicate with the arduino it uses a usb serial connection, that is its connected to the usb port, but it behaves like a serialport. The simple way to send data to the arduino is setting up stty and then you can do stuff from bash like echo “data” >/dev/ttyUSB0 and voila it receives the data.

Here is the prototype setup in all is lousy light condition for mobile cam glory.

There are 5 different meters and they all use PWM, without any capicitors or filters, and it just works, most of the time. Its coded so that when its send a string like 23#34#23#34#34 terminated by a newline, it adjust the displays to the values.(0-254).

Now the next part is to make some kind of script to read relevant information and pass it along to the dashboard, since i use linux some information is available trough acpi as virtual files. But the hunt for easy accessible and relevant data has started, i would really like to display bandwidth usage but so far i haven’t had any luck figuring out where it resides.

Depending on where you start the iteration you get a a different root, and requiring a different amount of iterations. That’s self-evident. The “funny” part is that when searching for complex roots there are areas in the complex plane, where a very small difference in starting point gives different roots, and with remarkable difference in the number of iterations.

This is a plot where each root in the polynomial x^4+2 have been assigned a different color. And each point is colored according to which root a iteration starting here finds.

Now thats the mathematical part of it. Now to the beautiful part or at least more fascinating part. The pattern reapeats it self, as a fractal, when you zoom in.

So i modified my code to zoom in, and i used a diffenrent coloring scheme where i only colored according to the number of iterations taken. This made it possible to generate a video zooming in og showing the rapeating patterns in “nice” colors.

Here a some videos :

4 roots (14.6 mb)
7 roots (50 mb)

Yes I know that its very large files, and maybe i will upload them to google video at a later time for easy viewing and less quality.

So I started to recreate the classic oldskool game Xonix, it’s a game I really like. So simple and addictive. It’s not the first time I’m coding it, I have made it as an applet about a year ago (Xonix applet). As well as being a fun game to play I find it a fun game to code too. Though I have had my share of frustrations. The basic functionality is a fillalgorithm, that has to fill an area on both sides of the line / trail you make with the ‘pilot’. This has to be fast and efficient – nobody likes a game where you have to wait for updates.

When I first made the game i found a neat fill-algorithm. (flood fill wikipedia). So it should have been a piece of cake to implement it in J2me, its java… I deliberately choose not to reuse old code, as I feared it would be horrible ugly. And a course in datastructures and algorithms should have given me some tools to make a better / cleaner implementation. Then the woes began. J2ME, has no ArrayList it has vector and a stack, and the are not generic so no typecasting. I made a version using Vector, but somehow i managed to use all the memory. When I look back I have a nagging suspicion that the Vector isn’t to blame – but rather me that somehow feed it to much data. No matter what it was I got rid of the Vector and started using arrays, and using indexing like in images or c-“double”arrays (index = x + y * WIDTH). Finally it could fit in memory.

And then I started looking for graphics, a nice game really depends on nice sprites – much more than a beautiful algorithm. I couldn’treally find any and its quite painful, at least for me, to make sprites. It gets real ugly, real fast – hmm no it gets real ugly real slow, because i’m no good at creating graphics. Well the frustrations grew and I ending up abandoning the project. The basic gameplay works, but is buggy and as mentioned the graphics sucks.

All in all it was quite fun programming, and some day i might give it another go.

I bought myself a new mobile, a Nokia 6300, it’s got all the bells and whistles. Hmm well at least those I could afford. I choose this mobile because it has : Java, mp3 -player, bluetooth and memorycard.

• specifications from nokia
• review from mobilereview.com

I must admit that i might be a bit of a nerd, so I just had to code something for it. And after “hello world” I found a small and some would say useless application to code.

FreeVibes

I must say I got inspired by vibelet and the article in wired ( Hold the Phone, It’s a Sex Toy ). As the title suggest, its well vibrating. I think that vibelet – though i haven’t seen their program, must be making quite an profit. Because getting a java-enabled phone to vibrate constantly, is quite easy.

So now its Time for FreeVibes, a free software version.

That’s the fancy splash screen	And when its in vibrating mode, this little duck is there. And now why a rubberduck ? ( answers )

If you want to try it out, here are the jar and jad files. Just put them on your java-enabled mobile phone. I have just tested it on my telephone, It should work on any new mobile (with java) :

Jad File
Jar File
Source code

Installation

1. Download the jar and jad file and place them on the phone in the same directory.
2. Run the applet
3. Have fun

Technicalities

Getting things to work with ubuntu feisty fawn.

I use SUNs java 6 and the wireless toolkit for the J2me.

Nokia has a nice area with information about coding for their phones (forum.nokia.com). But i didn’t have any success using their eclipse plugin and carbide.j seems to be a windows application. But eclipseME worked like a charm.

When setting up a device for EclipseME i had to make sure that it was MIDP 2.0 and CLDC 1.1. It wasn’t the default and the Nokia 6300 can’t handle MIDP 2.1.

They code and design is inspired by Nokias tutorial on making MIDP 2.0 games.

The images I used are from the openclipart collection, hacked together with GiMP and Inkscape, and I use obexftp to transfer the files to the phone.