softwarepoets

Time to cook, timing to cook

2011-08-05T21:07:00.000+02:00

For awhile I wanted to get into Sous Vide cooking, because it is

cool
involves tinkering with hardware
and is featured in the book "Cooking for geeks".

There are numerous instructions to be found on the web, but somehow, because it is half of the fun, I decided to start to design my own solution. Partly because our local hackerspace "baustelle Hamburg" once tried to organise a Sous Vide cooking event (but we were just getting started with everything, so we had to cancel it - but we have a nice poster!).

Essentially Sous Vide cooking involves food which is sealed in a vaccum bag and put into water of a precise and predetermined temperature. Professional cooking equipment can be very expensive because you need a good temperature control, and since it is not really a mass market, I guess there is quite a big profit margin.

I will either use a rice cooker or a slow cooker, which needs to be modified in order to keep the temperature. To achieve that, I use a microcontroller (Arduino) and a TRIAC based switch to turn the rice cooker (or whatever) on and off using a PID controller.

Essentially it all boils down to choosing the right ingredients. You need a good PID library, a versatile Arduino which is small enough to fit onto a PCB provided by tinkerlog.com and some electronics skills. I already made some prototypes on a bread board and I am currently designing a PCB board, which is not ready yet, but should somehow work.

The biggest problem with this solution is that it uses a fairly lame temperature sensor. The LM 235 has an accuracy of about +/- 1 degree and I am still looking for a cheap and easy alternative. Or I design the sensor in a kind of modular way, so that I can make experiments with other sensors.

BTW, I never can make up my mind which blogging system I like more: this one here, which is driven by blogger or posterous where you can have a look at http://justjoheinz.posterous.com

Ah! And if you have any kind of your own Sous Vide stories, please share!

baustelle Hamburg

2011-03-06T10:41:00.000+01:00

Long time - no updates, but I had been very busy the last months. For a year or so, I had been increasingly involved in open hardware and conducted experiments with the Arduino platform of microcontrollers. I also got a Makerbot 3D printer and started to build my own Prusa Mendel printer.

Doing that resulted in meeting lots of interesting and funny people. We had regular meetings and decided, that we wanted to have a real place where we could meet. So the idea to start a Hackerspace in Hamburg was born. In Germany the term hackerspace has probably some odd connotations. It is almost always perceived as a computer space where people break into other computers. Well, I don't do that (yet :-)), but when you start to look around at other countries and visit for example the /tmp/lab in Paris or NYC resistor in New York or the Open Design City in Berlin, you will notice that they always have the idea in common that technology and creativity go hand in hand, and are blended into new ways of making things, which are way beyond the traditional uses of computers.

The last sentence is of course not true. When computers had been built, their first use, was to connect them to the real world. In order to control machines, to visualize algorithms (the first versions of LOGO actually operated with a real moving robot turtle). We somehow lost the notion that computers can do something in the real world, being content with IDE's, programming languages, word processors, feeds, emails and, and, and... we completely missed that you can for example use your mobile phone to switch the lights in your house on and off.

To cut a long story short, we founded the "baustelle Hamburg", a DIY-hackerspace.fablab-mashup based in Hamburg, Germany. Currently we are sourcing stuff, seeking for funds, built the location (based in the excellent co working space betahaus). We organize meetings and really get going.

If you would like to get in touch, just drop a comment here (English speaking), or have a look at http://wiki.baustelle-hamburg.de/kontakt (German).

Software for Refarm the city/balcony

2010-05-02T18:14:00.001+02:00

I am currently in the process of writing the software for my farm. As usual I took the inspiration from Refarm the city. A pity - they seem to have a brilliant tool available, but my attempts to get in touch failed, and hence I just got my inspiration from their look and feel, and started to write my own little thing using Processing and the excellent controlP5 library.

You can see the humidity sensor to the left, the light sensor in the middle and a general status for the plant to the right.

Refarm the city continued

2010-04-25T15:03:00.000+02:00

Making the best of this sunny sunday afternoon, I continued to work on my microcontroller driven garden project. My first gravity based water supply quickly revealed that the pressure is to low. I also wanted the Arduino to control the water flow, hence I had to order a magnet valve to stop and start the water hose. Additional pressure has to be generated using a water pump. I found a cheap one with Comet Pumpen.

In the pricture above you can see the new water distribution system. Unfortunately it does not work. I guess the parts which I got from a pet store are for air supply and they do not withstand the pressure generated by the pump.

A quick look (above) at the water pump (right), magnet valve (middle) and the "server box" to control the water flow.

Power is managed by a rechargeable lead battery and a prototype board for a relay switch which takes the 5V an Arduino can generate to trigger the relay switch so that the magnet valve and pump can start to operate. This is my first operational soldered PCB (even including a diode which kills the electric current generated by the collapsing magnet field inside the relay. I used a standard 1N4001). Sofar I just trigger the relay using a battery. This is agile hardware development at its best!

Refarm the city

2010-04-18T12:31:00.000+02:00

This weekend I had been sitting on my balcony and had been wondering how I could protect my herbs I need for cooking from drying up, during the periods when I am not at home, travelling for work.

A quick look at the internet brought a project to my attention, which I found very appealing: Refarm the city. Turning my balcony into a Arduino based lab for farming? Deal! So I started creating the water basin.

A box of water bottles turned upside down, will provide an environmentally friendly water tank.

Drill some holes into the caps.

Connect the bottles using sokme tubes and connectors from the nearby fish shop.

Wired everything up.

Some additional controls.

Final outlet. Still need to find a 5V magnet valve to control the outlets.

Prototype for a humidity sensor.

To be done: Construct a water and rain proof shield for the microcontroller to send information to the base station.

Making a MakerBot

2010-04-18T09:42:00.000+02:00

Last weekend a group of tinkerists gathered to build a MakerBot. The MakerBot was bought by Good School, and assembled by Palo Altona.

In case you want - a MakerBot is a 3D printer, capable of "printing" 3D objects out of molten plastic. It is a very fascinating technology. There is plenty of information available in the internet. One of the more fascinating projects is the RepRap, a self replicating printer, e.g. the vision is, that the RepRap will be able to print itself one day.

Or as Chris DiBona, a Google employee, said: "This is China on your desktop."

UML Model Validation

2010-04-09T22:17:00.000+02:00

Today I'd like to share a small video with you which raises an important issue: UML Model Validation. Being an extremely complex language without proper understanding of the rules and constraints of the UML Model it is easily possible to create invalid UML models. That is why there are standard documents and also a certification program for UML to help people look under the hood of the diagrams.

And here is the video by a tool vendor (*) to solve the problem of model validation
http://www.download-omondo.com/model_validation.swf (I took it from a LinkedIn discussion)

I love the part in the middle of the video when the model is actually validated. In UML terms the error message is absolutely correct. In terms of human readable error messages there seems to be a problem, as illustrated by the video (you need to have sound).

(*) Please note that I do not have any kind of affifilation with the vendor, nor know the tool particularily well. Having said that I do not want to say it is a bad tool, I also do not want to endorse it. The problem is very common among UML tools and usually they tend to be decreasingly useful when the constraints to be validated get more complicated.

Arduino robot project pt. 2

2010-04-09T11:21:00.000+02:00

Yippie, the robot chassis arrived a while back from Honk Kong in this wonderful wrapping. While it had been on its way, I had been busy soldering my first InfraRed distance sensor. I even had to experience the disappointment of the whole thing not working after I transferred it from my breadboard, but in the end I just figured out that there was a cable missing.

Yesterday I also had the pleasure to attend my first Palo Altona Drinkup - a group of tinkering specialists based in Hamburg. If you are interested, have a look at the website, there are regular meetings/drunkups.

Arduino robot project pt. 1

2010-03-14T18:09:00.002+01:00

Inspired by a post which I found Fabian Steeg's blog, I purchased the Arduino Microcontroller and started to assemble various little projects. If you are in Germany I highly recommend to get the controller from Fritzing.

When I started wiring the hardware I purchased a book by make:

It is really a funny book and a nice introduction into electronics, with all kinds of weird experiments. Essentially I am into the idea that they invite their readers to break stuff.

After some initial brain storming I came up with the idea, that for my first real project I'd like to create a robot which is capable of making movies. Hence it should be able to move around without bumping into stuff and have a pan and tilt tower where the video camera is mounted.

After some research I found a twin gear box made by Tamiya:

This will replace the standard motor for the tracked vehicle kit (also by Tamiya).

The gear box is already assembled and I am still waiting for the chassis to arrive from Hong Kong. Meanwhile I am constructing the IR Sensors and the pan and tilt tower. The two required servos are already working. Now it still requires some metal work to put all the pieces together.

Xtext Valueconverters

2010-02-21T15:17:00.001+01:00

I just stumpled across a link which explains very nicely how to use value converters in Xtext and thought I just cross post it:

Petter's Random Thoughts on Software: Xtext Valueconverter

The blog post had been written by Petter Graf, probably you would like to check out his other postings.

Xtext, guice and IExecutableExtensionFactory

2010-02-16T19:12:00.000+01:00

Consider that you have written an eclipse plugin using Xtext and added some custom made commands, handlers, menu items ... to your code.

Quite possibly you will want to use google guice sooner or later in your custom code, either to use the advantages of this dependency injection framework yourself, or to access some of the objects which are provided by your xtext plugin, and which you want to inject in your code.

In this case the IExecutableExtensionFactory mechanism provided by eclipse and in a more concrete manner either the subclass of org.eclipse.xtext.ui.core.guice.AbstractGuiceAwareExecutableExtensionFactory which is automatically generated for your ui plugin of the Xtext language. You can also subclass the AbstractGuiceAwareExecutableExtensionFactory yourself, if you do not want to or cannot modify your module definition for guice generated by Xtext. Looking at the generated example should be enough documentation to get you started.

Once you are done, all you need to do is to add the factory in front of your class descriptions in any of the extensions you are using and the class becomes part of the injection container and can "receive" injections:

<extension>
    <handler class="my.package.MyFactory:my.package.handler.SomeHandler" commandId="commandid">
   </handler>
</extension>

That's all and you are ready to go.

TMF Xtext 0.8M5 is out...

2010-02-03T14:29:00.000+01:00

I could not find any release notes yet, but you may point your update manager to

http://download.eclipse.org/modeling/tmf/updates/milestones/

in order to get the new release.

Referencing metamodels in Xtext and using them in xpand

2009-12-18T09:32:00.000+01:00

There are quite a few resources out there what you need to do if you want to reference a DSL in another DSL, say you need to refer from BDSL to metamodel types of ADSL.

In short you need to figure out how to configure your xtext project (add a dependency to ADSL and sort out the genmodels attribute in the xtext configutaration, more about that here) and you need to find out when to use the platform URI and classpath URI specifications to refer to the metamodels and imported models. And there is the importURI attribute which takes cares of importing your model into another model.

All that can be found in the documentation and various other resources of Xtext, however it took a good deal of time to find out how to make xpand (aka the "Generator" ) recognize your combined model. I always had all kinds of exceptions, basically stating that the xpt templates do know nothing about your referenced model, even so everything works fine in the editor.

The solution is short and simple. You just need to add a line in the MWEReader component of the workflow:



<component class="org.eclipse.xtext.MweReader">

<register class="namespace.of.BDLStandaloneSetup"/>

<register class="namespace.of.ADSLStandaloneSetup"/>



... blablabla

</component>

The line for BDSL will already be present, you just need to add the extra line. And maybe you will also need to register the generated EPackages to the StandaloneBean, as usual.

Wordle - a toy for tag clouds

2009-11-19T10:21:00.001+01:00

I just had been toying around with Wordle - a website which allows you to quickly generate fairly flexible word clouds to visualize arbitrary textual content. I am currently looking into ways to visualize content (mostly based on textual models of course). There is another resource I'd like to share. A very powerful layout engine which can be used within have is prefuse, its API is very easy to understand and fairly well documented. Check out the gallery, if you'd like to know more.

Impressions of Google wave

2009-10-04T00:13:00.000+02:00

The other day I received my Google wave account. If you do not know what wave is: some people said that it is like email on steroids and in a way that is true, but there is more to it.

I recommend to watch the first part of the presentation held at the Google I/O conference:

The interesting concept about wave is that it rethinks how communication could be done using the internet and tries to find a solution for it. The solution might not be perfect, but so far I like it. Time will show.

The most interesting part of Google wave is that you can write robots for it, which interact with the communication. For example a robot could analyse the conversation and draw a diagramm according to the content. Writing robots is also really easy. A very good tutorial to get you started can be found here. There are APIs for java and python available. I completed the example in about 5 minutes and I am currently writing a small robot myself which will analyse a DSL to draw use case diagrams as a prototype. Apart from the robot API there are also different scenarios where and how you can extend wave.

Another nice example of the usage capabilties of the platform can be found here:

Are you using wave, have you written your own extensions? I'd be glad to hear. You can also contact me under justjoheinz@googlewave.com or just leave a comment.

NetBeans RCP

2009-09-18T16:01:00.000+02:00

During the past days I had been looking into the NetBeans RCP since I wanted to prototype a GUI rich application. I am actually amazed by it now, and wonder why I had invested the time to study the Eclipse RCP.

I think NetBeans has a couple of advantages over Eclipse when it comes to building GUI applications.

excellent GUI builder
very good module system
a mechanism for decoupling called lookup
learning curve is not very steep as you stay in the Swing idiom and do not have to learn SWT
good tutorials to get you started
a useful set of wizards
very good API to build explorers, editors, property sheets etc.

So far, whenever I build something which was against the NetBeans RCP idiom, it was fairly easy to refactor the code to apply what I had learned. There is also a book available in german and in english. Have a look here. I wrote a small review for it, which can be found at the end of the description, telling you what to expect.

If only Netbeans had better integration with modelling, such as Eclipse and EMF! Well, I guess we have to wait for Netbeans 23.1 M9 to see that.

Making xtext, eclipse and guice work together

2009-08-14T07:32:00.003+02:00

There is a new entry in the xtext documentation dealing with enabling guice for your Xtext Editor.

This is pretty useful, though the same concept used to work before it only found its way into the documentation now. Hence I just wanted to share that information with you. Works really well.

<extension
point="org.eclipse.ui.editors">
<editor
class="<MyLanguageName>ExecutableExtensionFactory:
org.eclipse.xtext.ui.core.editor.XtextEditor"
contributorClass=
"org.eclipse.ui.editors.text.TextEditorActionContributor"
default="true"
extensions="ecoredsl"
id="org.eclipse.xtext.example.EcoreDsl"
name="EcoreDsl Editor">
</editor>
</extension>

Please not that MyLanguageName is actually the name of the factory you can find in your src folder of the UI-Project under your main package.

And now, if you'd like to write some ActionHandler for your xtext outline view, you can do just the same. Simply prefix the Handler class with the factory, and there you go!

Xtext 0.7.2 released, but...

2009-08-12T16:08:00.002+02:00

I get

Cannot complete the install because one or more required items could not be found.
Software being installed: Xtext Runtime (Incubation) 0.7.2.v200908120607 (org.eclipse.xtext.runtime.feature.group 0.7.2.v200908120607)
Missing requirement: Xtext Generator (Incubation) 0.7.2.v200908120607 (org.eclipse.xtext.generator 0.7.2.v200908120607) requires 'bundle org.eclipse.xtend.util.stdlib 0.7.2' but it could not be found
Cannot satisfy dependency:
From: Xtext Runtime (Incubation) 0.7.2.v200908120607 (org.eclipse.xtext.runtime.feature.group 0.7.2.v200908120607)
To: org.eclipse.xtext.generator [0.7.2.v200908120607]

I will investigate that later.

Setting up guice for xtext/TMF and parsing rules for validation

2009-08-06T17:06:00.003+02:00

I am by no means a Guice expert, but here is a small code snippet which works for me, to setup TMF/xtext with guice. The main method may contain simple @Inject annotations to get your correct implementations injected.


public static void main(String[] args) {
BausteineStandaloneSetup setup = new BausteineStandaloneSetup();
setup.doSetup();
Injector injector = setup.createInjector();
Main main = injector.getInstance(Main.class);
main.write();
}

I currently use this to preparse arbitrary files which are not in my DSL and transform them. I do not want to rewrite particular checks for Rules, e.g. to verify if an ID is in the correct format, hence I just get the Parser injected and invoke the rule checking with a StringInputStream.
This looks roughly like this:


@Inject
private IAntlrParser parser;
@Inject
private BausteineGrammarAccess access;
...
InputStream inputStream = new StringInputStream("baustein " + name);
IParseResult result =    parser.parse(access.getBausteinDefRule().getName(),inputStream);

There might be a more efficient way to do this, but currently I am quite happy with the solution. I guess I could try to use the lexer instead of the parser if I only want to check for terminals, but I need to extend the checks anyway.

Lego Architecture

2009-08-02T14:26:00.000+02:00

Available in the States: Lego Architecture
Shown in the picture is the Guggenheim Museum by Frank Llyod Wright.

Every great architect is — necessarily — a great poet. He must be a great original interpreter of his time, his day, his age.

Couldn't have said it better.

Architectes: tous imbéciles

2009-07-29T18:13:00.006+02:00

A nice quote by Gustave Flaubert in his "Dictionnaire des idées reçues" (Dictionary of common ideas):

Architectes: Tous imbéciles. Oublient toujours l'escalier des maisons.(*)

(*) roughly: All idiots. Always forget the stairs of the house.

Of course there are exceptions to the rule as demonstrated by M.C. Escher, chief evangelist for cyclic dependencies.

Another very nice definition can be found in the "Devil's Dictionary" by Ambroise Bierce.

Architect, n. One who drafts a plan of your house, and plans a draft of your money.

I just realized that my architecture quotes are always slightly negative. Well, not all of them. The positive ones are usually by architects and not about architects (D'oh! I just wanted to be more positive - you may find some quotes under the musings label). So - in case you have positive quotes let me know. Just drop a note, leave a comment or draw a plan or use a fancy communication diagram @:)

UML Pinup Calendar

2009-07-29T17:53:00.000+02:00

Christmas is around the corner, so YOU NEED THIS:

Don't forget to create your own profile and apply stereotypes to your calendar. If you are unhappy about the price tag, leave a comment. I am sure we can strike a deal so that you get a useful gift for your beloved ones (boss, colleague, wife, girlfriend...).

Dark Factory of Mass Production

2009-07-27T09:46:00.000+02:00

This weekend I had been on a flea market strolling about and buying books for a bargain. For my own amusement I usually drop by at the section with the kid stalls (they usually get some space for free and do not have to pay a fee). I purchased this Yu-Gi-Oh! card, which I think is a nice example of early IT education (though most of the customers will not be aware of that - yet).

I like that the factory constructs two monsters (thus emphasing the value of factories to create families of objects). I wonder if Yu-Gi-OH! also knows a Builder pattern card? I also like that the factory is called "dark". It stresses the overuse of factories in the realm of testing, where languages such as java, would very often allow us to avoid factories and use mock objects instead (though many mock object framework encourage you to use interfaces for mocking one can easily mock classes too, thus avoiding unnecessary factory code).

Operating manual for spaceship earth

2009-07-02T15:45:00.000+02:00

I am currently reading the book Operating manual for spaceship Earth by Buckminster Fuller. I stumpled across a quote just at the beginning which relates very much to my approach of doing consulting (in the area of systems analysis):

About to provide a new snapshot release for components4oaw

2009-05-27T23:15:00.001+02:00

Good news, we are about to release a new snapshot release for the adapter to Enterprise Architect and openArchitectureWare.

Ueli is working on new features for statemachines. I do the release management (getting angry with maven as usual). I still have to work on switching to a normal eclipse update site and hope to manage the transition soon. For news on the release check here on the blog or have a look at components4oaw. I hope I will be done by this weekend and you can change to a pre-release of version 1.7.0

By the way: we are always very grateful for feature requests and bug reports.