jan.krutisch.de

• 28 Jul 2010 » Fighting those rotary encoders

  Another halfbyte day. This time, I’m finally doing serious electronics work. One problem that bugged me for quite some time now and that I definitely needed to get ticked off my todo list was how to properly read rotary encoders with the Arduino slash AtMega.

  There are numerous ways to do that and most people will tell you that you ideally need an interrupt to do it right. Using an interrupt might be okay, if you want to attach one encoder to your project, but it all falls apart as soon as you want to have more of them (in my case, the current target is as much as 16 encoders). Last year, when I tried to build my Budget “monome”, I already had a simple setup involving some shift registers in place, but somehow, reading the encoders always failed miserably.

  I then stepped back from reading specs and the arduino wiki and tried to learn from the pros. The midibox.org project of course has some pretty advanced encoder code, but, to be honest, I didn’t really feel like trying to find out what roughly 300 lines of hand optimized PIC assembler will do.

  Finally, a few days ago, I took a second look at the Minicommand project from wesen (of ruin&wesen fame). The whole project is open source and it is pretty readable as well, as it is highly structured, maintainable C++ code.

  After a day of wrestling with my (undocumented) last years hardware and my slight inability to read data sheets, I now have 8 encoders running smoothly in hightly unoptimized Arduino code, which is more than I had hoped for for today.

  What’s next? The encoders I use also have buttons built in and I already have a third shift register in place to read out those buttons – Something for next week. And then I plan to replace the arduino I currently use for testing with a jeenode, so that I can use the encoders over a wireless connection.

• 14 Jul 2010 » The beginning of a new era

  Today was a pretty fun day. I slept in, I worked a bit on some stuff that I never got around doing before (like cancelling old insurances, mags I don’t read anymore and things like that), cleaned parts of our flat and the went to the open air pool with the girl. I can’t say the day went exactly as I planned it to go, but the main reason behind it was that I didn’t really have a plan.

  What was special about this day? Well, for once, I am no longer on vacation. Plus it is wednesday. Which means that this was actually the first day I was able to use from my newly aquired 10% time off. I’m officially on 90% (or, put differently, 36 Hours a week) since the first of June, but with the long vacation and all, today is a real first.

  I did it yesterday, and I will do it again: From now on, every free wednesday will be called “halfbyte day”. A day for tinkering. A day for making future. A day for doing stuff that’s outside the scope of my “normal” mindmatters routine, which is about developing software for people using the web, as we like to call it these days.

  halfbyte is my twitter name, my github name and also my demo scene pseudonym for at least 15 years now. I know it’s kinda sucky and there are loads of nybble jokes out there, but I grew fond of it and I like to think of it as my more experimental, less professional alter ego.

  As it seems, both my company (beforementioned mindmatters) and I think that it is a good idea to emphasize on the differences between the professional web developer Jan and the tinkerer with soldering iron and oscilloscope halfbyte. Let’s see how this turns out.

  Both halfbyte.de and halfbyte.org are finally back under my control, and I am currently trying to find out what I could do with them.

  I expect great things to come from this, and so should you. Stay tuned.

• 04 Jun 2010 » RailsWayCon Recap

  On wednesday, the second RailsWayCon conference, organized by the Software&Support team, in Berlin came to an end. This time, I had not one, but two talks to give and this put me in the rather unfortunate position to have spent more time in my awesome hotel room finishing the slides than to attend other people’s talk.

  As last year, the programme was pretty good. The omnipresent Yehuda didn’t fail to impress with his talks on Rails 3 and jQuery usage in Rails, always good to hear what’s going on in the core team. I also particularly enjoyed the talks by Michael Mahlberg and Jens-Christian Fischer, one on the SOLID design principles and how to use them in Rails applications and the other one being a great session to explain and actually do Coding Dojos/Katas. I guess we at mindmatters need to get back to them, it’s a lot of fun and you learn a ton on pair programming while doing it.

  Also really good was Sven Fuchs’ talk on the i18n gem and the underlying design principles. And of course, Jonathan Weiss didn’t fail to deliver, I enjoyed his talk on CouchDB and missed the other one, though.

  As usual, there were also some more mediocre talks, with people either being too chaotic or too insubstantial in their presentations – but nothing was actually able to beat the awkwardness of the panel on “Designers vs. Developers” that was part of the webinale conference of RailsWayCon was only a small part. I really could do without 5 people sitting on stage discussing issues we solved like 5-6 years ago (E.g. the whole “pixelperfect” webdesign issues) while completely ignoring the issues that are currently our biggest problem like the fact that print designers usually have no clue whatsoever on information architecture, UX design and agile processes.

  In contrast, I very much enjoyed the Panel on Tuesday evening, there was beer and some good discussions. One minor downside though was Michael Johanns try to kind of artificially push the discussion into a general “Rails in the enterprise” discussion.

  Generally I would give the advice of not focusing too much on Enterprise problems. There were quite a few talks on enterprise features and enterprise patterns or ways to optimize projects for the enterprise. While it is generally understandable as S&S have their roots in the rather enterprisey Java market with conferences like the big JAX probably being their cash cow, also several members of the programme commitee are consultants with a classical enterprise track record, I still think that it doesn’t really fit Rails too well. This also kinda shone through during the panel discussion on tuesday evening, where I got a loud round of applause for just raising the question why we focus on the enterprise so much.

  But that’s a point for another post – My personal and general sentiments against working in the enterprise field are rather strong and I already promised on twitter to elaborate a bit on that.

  Last but not least I also very much enjoyed the dinner on Monday with the Railslove guys and Dennis and the post-conf meetup on Wednesday with the berlin guys like Mathias, Jonathan, Phillip and Thilo.

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• 20 Apr 2010 » The shift that wasn't meant to be

  I seem to have upset the gods of transportation. Or put differently: My personal flight success rate for this year is currently a whopping zero percent.

  Okay, a little context can not hurt. Wolfgang and I had quite a busy week ahead of us: We attended Berlin’s very own re:publica conference from wednesday to thursday and wanted to fly to lisbon for this years edition of shift, where both of us had talks to give.

  On thursday night it became clear that this would probably not happen that way. On friday, a probably rather frustrated Pedro (because at least 50% of his international speakers sat anywhere in the world BUT lisbon) asked me via email if I could probably hold my talk remotely. I was a bit reluctant at first but agreed to do it later on. No, the experience of that wasn’t too enjoyable, because I really like to have direct feedback by the audience which isn’t quite possible if you 1. can’t see the audience and 2. can’t really hear the audience as well. Seems that it wasn’t that bad for the audience and I got quite some good feedback on it from the organizers, but I really would prefer attending the next conference in person, thank you very much.

  Now I please don’t want to talk about that anymore. I had an enjoyable Sunday under the sun of Travemünde, while it reportedly poured in lisbon. That’s at least a descent form of compensation.

  On to the talk: As usual with my talks, I’m not too happy about the end result – it didn’t fit into the 25 minutes I had, it didn’t manage to bring the points across that I had in mind, but hey, I could probably talk for several hours on Open Source Hardware and 30 minutes is a pretty harsh time constraint – On the other hand I really need to get better at this. Next stop will be RailsWayCon in Berlin on the end of may, where I will be holding two talks – One very very technical (on my mongodb experiences) and one that’s more like this one on fun projects to improve your conding skills.

  Open source hardware is really nothing new, the idea has been around for almost as long as the concept of open source (which didn’t have that name until the beginning of the nineties), but somehow it took quite some time to gain momentum on the internet and find it’s ways and niches to become as successful as it is right now.

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• 31 Jan 2010 » The musichackday that wasn't meant to be

  As my coworker Florian would put it: Damn the sh*t f**k. For us (us being the hamburgian musichackday tourists Michael, Wolfgang and Jan with a taste for low budget travel plans), the musichackday was over before it even started. We patiently stood in line at the Ryanair dominated airport in Lübeck, but, really, we should have known better. Not a single Plane left or arrived at Lübeck after 15:00 on Friday. It was snowing like hell (a very cold hell, that is) and the snow ploughs tried their best, but, heck, it was almost impossible to drive safely with a car out there, so it probably wasn’t a too bad decision to not try to land or start there. Safety first, safety first.

  

  But, being a screwed Ryanair customer, it was clear for us that we had no chance to get to STHLM in time, except for making the travel at maybe 3 times the expense originally planned.

  This obviously being the most awesome hackday evar, I’m still quite disappointed. But I repeat myself. Wolfgang suggested early on that we should hack on regardless and so all of us met on Saturday, started with a good Breakfast with leftovers from the porkcamp and dived into the projects we had originally planned for Stockholm.

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• 27 Jan 2010 » iPad it is

  this article has been updated on the 28th of January to correct some errors and clarify a few points

  First off: I think the name is a poor choice. The web, especially the twitters seems to agree. I would have loved all the other names that flew around during the last days, like iBook, Canvas, Palette, whatever.

  With that out of the way, I am pretty baffled by both the product itself but also the reactions to it.

  What can I say. No multitasking feels weird with a device that can run special versions of iWork on it. (Let’s hope they do a lot of state saving and the apps start fast). Apart from that, the whole thing feels like an extremely solid, well designed piece of hardware/software.

  Now here’s the real problem: While OS X on my Mac has it’s proprietary edges, the system is mostly open. iPhone and iPad are, by default, pretty much closed devices. And this leaves a lot of questions unanswered. For example, it restricts your music buying to iTunes, which is good for noone but Apple. This is, for example, not the case for iTunes on my Mac, simply because I can drop any piece of music, on CD or as mp3, into iTunes. But there’s a glimpse of hope…there are some changes (yah, NDA fun at work, so I cannot tell anything specific) in the 3.2 SDK that might allow Applications to add files to to other Applications. Maybe. We’ll see.

  And now there’s iBooks: Will it restrict Book buying to the iBooks store? We don’t know yet, but at least it is based on a standard (ePub), so it might be possible to add non-DRM books (like my beloved pragprog series) directly to the iBooks app. But what about the DRM format? Will it support the defacto standard Adobe DRM and by that opening your iPad to the hundreds of titles that publishers sell for, e.g. the Sony readers? I somehow doubt that, but we will hopefully get some details on that very soon.

  For me, somehow, the closed nature of the iPad is much worse than the closed nature of the iPhone, probably because it’s closer to a “real” computer and I like those to be as open as possible, thankyouverymuch.

  Still, I do not agree with many commenters that the iPad is an underwhelming supersized iPhone and nothing else. Or that it cannot compete with netbooks. Or that there are no usecases.

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• 26 Jan 2010 » An update on the web synthesizer

  After the last post on my crazy “synth in a browser” idea, I tried various other concepts to bring the idea to life. I am not very happy with the current state, but definitely see potential in some of the ideas.

  After the rather brutal failure of the streaming idea (I guess, I could, with some serious hackery and a little more systematic approach, trim down latency to around 10sec which might be still way too much to be anywhere near beeing useful), I tried to explore other possibilities. If generating the sound on a server is out of question, I need to generate it in the client. Well, duh.

  Now, conventional wisdom says that this is probably too much for the obvious client choice: Javascript. Plus, there’s no interface for “streaming” on the fly synthesized audio from javascript.

  But, as it seems, conventional wisdom was invented before Google Chrome, the V8 javascript VM or Safari and the Nitro engine came to life. I personally think that conventional wisdom was invented for a IE 5.0.

  So it should be at least worth a try. But even if it is possible to write a realtime software synthesis system in javascript (and I am only spilling a few beans when I tell you: it IS!), this leaves me with the problem of actually playing the generated sound.

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• 13 Jan 2010 » The Hudson Siren - Small pieces loosely joined

  

  A strong, intrusive indicator for continuous integration failures is extremely useful to keep software quality high. People tend to forget the CI stage if nothing seems to go wrong. And while the usual CCTray-Stuff “kind of” works, a more physical approach may be in order for larger teams. While large “information radiator” screens might be desirable, we chose to go a lot cheaper. One of my colleagues, the recent Rails convert Christoph actually took the first, most important step and implemented the actual notification hardware, using freely available “police lights”, a simple USB driven relais board and a Linksys NSLU2. His work was pretty outstanding: It involved crosscompiling USBLib for the NSLU2 (not to forget installing Debian on it), wiring it all together and then writing some kind of network protocol for it. Now, the actual protocol is pretty simple: Open a telnet connection (aka TCP/IP-Socket) to a specific port and send a command like “BLINK 3 RED” to it. This is, of course, “Keep it simple stupid” aka KISS at it’s best.

  Except that now we were faced with a problem: Our CI servers are outside of our office network and you probably don’t want to expose a relatively insecure protocol (with an implementation that’s very likely to contain bugs an attacker could exploit). So, portforwarding from our firewall was out of question. In a very KISSy move, my colleague Timo set up some SSH tunneling and then wrote a simple Hudson-Plugin which would then use the above mentioned protocol via the SSH tunnel. This worked for some time but then we split up our CI server installations (and after that only Java projects could use the Sirens) and anyway, this was a bad kludge, so when the tunnel went down some day due to a server restart, we never restarted it.

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• 09 Jan 2010 » A most unusual hack

  Sometimes, you have to take a bath to make things come together. In my case, I was pondering porting the absolutely fabulous nanoloop to the iPhone platform. But that was only one piece of the puzzle. The other one was a podcast (Bitsundso) where one of the regulars (namely Thorsten Philipp) was explaining the brand new apple flavor of http streaming – Which is based on delivering a video or audio stream in small chunks (8-10 seconds seems to be a good value) and glueing them together using an extended version of m3u-playlists.

  But first, a bit of background. Nanoloop is a music synthesizer/sequencer for the Gameboy, more specificly for the Gameboy Classic and the Gameboy advance (those are two different versions). I am a proud owner of one of the Nanoloop 2.3 cartridges, wich are handmade by Hamburgian resident and 8Bit-Superstar Oliver Wittchow. Editing music with the not-exactly-rich user interface of a handheld game console (a screen and 10 buttons: Left, Right, Up, Down, Start, Select, A, B, L and R) is challenging. Managable and, as Youtube or even my very own Soundcloud stream testifies, with usable results, but, nevertheless, far from being intuitive. Oliver did his best to streamline the experience and to make everything as consistent as possible, but still.

  Now, my plan was (and still is) to either convince Oliver to port Nanoloop to the iPhone or to do a knock off of it myself. Here’s the problem: While porting the sound engine should not be a huge problem (both devices are using ARM architecture, plus the iPhone should be an order of a magnitude faster), the interface has to be completely different. Because the iPhone has no buttons. Well, strictly speaking it has four buttons and a rocker switch, but none of them are usable in your own software. What it has, though, is a touch screen. Multitouch, even.

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• 07 Jan 2010 » Eine kleine schwedische Meiereikunde

  Jetzt wo der Herr Siepert nicht mehr nur Foodbloggt, könnte ich doch eigentlich auch mal anfangen, Foodzubloggen. Ich hab da leider nicht so viel kulinarische Sexyness beizutragen wie ebenjeniger, aber jeder hat mal klein angefangen.

  Jeder, der mich ein bisschen besser kennt, weiss, das ich gefühlt ein halber Skandinavier bin. Ich bin fast jeden Sommer in Schweden, nach ’ner Woche da oben radebreche ich sogar ganz passabel Schwedisch. Auch Dänemark ist mir nicht fremd, im Gegensatz zu dem klassischen Dänemark-Urlauber kenne ich mich allerdings auf Seeland, Lolland und Falster wesentlich besser aus als auf dem “Festland”.

  Nundenn. Wie es das Schicksal wollte, verbrachte ich den Jahreswechsel auch in Dänemark, und zwar in Lalandia, ein Ort, den der geneigte Individual-Reisende vermutlich ganz abscheulich findet (Think: Dänische Version der Center Parcs), der aber den Vorteil hatte, ein ganz hervorragendes Schwimmbad zu besitzen und Ferienhäuser mit freiem WLAN. Schon sehr Massentouristisch (und über den Jahreswechsel erschreckend voll) und für mich sicher kein Ort, an dem ich drei Wochen Sommerurlaub verbringen möchte. Für unsere spontane Flucht aus dem Großstadt-Sylvester-Wahnsinn war es jedenfalls ideal.

  Aber eigentlich sollte es doch um Milchprodukte gehen, also wo war ich stehen geblieben? Ach ja. In Dänemark muss ich natürlich Ymer kaufen. Und dann kam meine Freundin auch noch mit Dingen aus Schweden (wo sie den ausgewanderten Teil Ihrer Familie besuchte). Und so entstand die Idee, dem geneigten Leser einmal kurz die Vorzüge der skandinavischen Meiereiprodukte nahezubringen. Denn ich stelle immer wieder gerade bei frischgebackenen Skandinavien-Neulingen fest, dass man sich nicht so recht rantraut an all die komischen Dinge, die sich da im Kühlregal stapeln. Was nicht weiter verwunderlich ist, denn erstens sind die Namen nicht selbsterklärend und zweitens ist die Schnittmenge mit den uns Deutschen vertrauten Milchprodukten nicht sonderlich groß.

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