Playing with OpenStreetMap resources lately I came to the point where I wanted to calculate routes between points based on the OSM data. Now there is GraphHopper to the rescue! It’s opensource and awesome!
“GraphHopper offers memory efficient algorithms in Java for routing on graphs. E.g. Dijkstra and A* but also optimized road routing algorithms like Contraction Hierarchies. It stands under the Apache License and is build on a large test suite.”
Some might know AmbiLight – a great invention by Philips that projects colored light around a TV screen based upon the contents shown. It’s a great addition to a TV but naturally only available with Philips TV sets.
Not anymore. There are several open-source projects that allow you to build your very own AmbiLight clone. I’ve built one using a 50-LEDs WS2801 stripe, a 5V/10A power supply, a RaspberryPi, and the BobLight integration in RaspBMC (this is a nice XBMC distribution for the Pi).
“Boblight is a collection of tools for driving lights connected to an external controller.
Its main purpose is to create light effects from an external input, such as a video stream (desktop capture, video player, tv card), an audio stream (jack, alsa), or user input (lirc, http). Boblight uses a client/server model, where clients are responsible for translating an external input to light data, and boblightd is responsible for translating the light data into commands for external light controllers.”
The hardware to start with looks like this:
I’ve fitted some heat-sinks to the Pi since the additional load of controlling 50 LEDs will add a little bit of additional CPU usage which is desperately needed when playing Full HD High-Bitrate content.
The puzzle pieces need to be put together as described by the very good AdaFruit diagram:
As you can see the Pi is powered directly through the GPIO pins. You’re not going to use the MicroUSB or the USB ports to power the Pi. It’s important that you keep the cables between the Pi and the LEDs as short as possible. When I added longer / unshielded cables everything went flickering. You do not want that – so short cables it is :-)
When you look at aboves picture closely you will find a CO and DO on the PCB of the LED. on the other side of the PCB there’s a CI and DI. Guess what: That means Clock IN and Clock OUT and Data IN and Data OUT. Don’t be mistaken by the adapter cables the LED stripes comes with. My Output socket looked damn close to something I thought was an Input socket. If nothing seems to work on the first trials – you’re holding it wrong! Don’t let the adapters fitted by the manufacturer mislead you.
Depending on the manufacturer of your particular LED stripe there are layouts different from the above image possible. Since RaspBMC is bundled with Boblight already you want to use something that is compatible with Boblight. Something that allows Boblight to control each LED in color and brightness separately.
I opted for WS2801 equipped LEDs. This pretty much means that each LED sits on it’s own WS2801 chip and that chip takes commands for color and brightness. There are other options as well – I hear that LDP8806 chips also work with Boblight.
My power supply got a little big to beefy – 10 Amps is plenty. I originally planned to have 100 LEDs on that single TV. Each LED at full white brightness would consume 60mA – which brings us to 6Amps for a 100 – add to that the 2 Amps for the PI and you’re at 8A. So 10A was the choice.
To connect to the Pi GPIO Pins I used simple jumper wires. After a little bit of boblightd compilation on a vanilla Raspbian SD card (how-to here). Please note that with current RaspBMC versions you do not need to compile Boblight yourself – I’ve just taken for debugging purposes as clean Raspbian Image and compiled it myself to do some boblight-constant tests. Boblight-constant is a tool that comes with Boblight which allows you to set all LEDs to one color.
If everything is right, it should look like this:
Now everything depends on how your LED stripes look like and how your TVs backside looks like. I wanted to fit my setup to a 42″ Samsung TV. This one already is fitted with a Ultra-Slim Wall mount which makes it pretty much sitting flat on the wall like a picture. I wanted the LEDs to sit right on the TVs back and I figured that cable channels when cut would do the job pretty nicely.
To get RaspBMC working with your setup the only things you need to do are:
Enable Boblight support in the Applications / RaspBMC tool
Login to your RaspBMC Pi through SSH with the user pi password raspberry and copy your boblight.conf file to /etc/boblight.conf.
The configuration file can be obtained from the various tutorials that deal with the boblight configuration. You can choose the hard way to create a configuration or a rather easy one by using the boblight configuration tool.
I’ve used the tool :-)
Now if everything went right you don’t have flickering, the TV is on the wall and you can watch movies and what-not with beautiful light effects around your TV screen. If you need to test your set-up to tweak it a bit more, go with this or this.
Unfortunately complex JSON can get a bit heavy on the structure itself with over and over repetitions of data-schemes and ids.
There’s RJSON to the rescue on this. It’s backwards compatible and makes your JSON more compressible:
“RJSON converts any JSON data collection into more compact recursive form. Compressed data is still JSON and can be parsed with JSON.parse. RJSON can compress not only homogeneous collections, but also any data sets with free structure.
RJSON is single-pass stream compressor, it extracts data schemes from document, assign each schema unique number and use this number instead of repeating same property names again and again.”
While I am using Xcode a lot lately I quickly got used to one or two keyboard shortcuts that come in handy once every while. This cheat sheet aims at bringing you a lot of shortcuts that are pretty hard to remember if you’re not using them all the time (at least for me).
After getting the server and the iOS client application to the people I’ve sat down and started doing something I have not done yet – writing a web application with no server side except a standard HTTP server.
Here’s a little demonstration which I will explain in more detail below:
The default Miataru service can be accessed through the client application with this URL: http://miataru.com/client – This will open a new browser window with a completely fresh session of the application. Since Miataru is all about control of your own data this webapplication does not store anything on any servers – every access to the internet is read-only and only to the Miataru service (just “GetLocation”). Oh – and by default it uses SSL to encrypt all traffic from and to the Miataru service.
You can start by entering DeviceIDs you know or you can – for test purposes – use a DeviceID I am providing for test purposes: BF0160F5-4138-402C-A5F0-DEB1AA1F4216
Oh and if you want to see the device moving on your iPhone just use the miataru iOS client and scan this QR code here:
So that was easy – but if the application does not store anything on any server, how does it maintain the Known Devices list between browser sessions (open/closes of the browser) you ask? – It’s using HTML5 WebStorage to store these information locally in your browser. This has the advantage of being completely local, but also the disadvantage that it is not shared between browsers or machines.
Like usual this whole application is also available completely free of charge and open-sourced to be used, edited and installed on-premise if you like.
“A Dark Pattern is a type of user interface that appears to have been carefully crafted to trick users into doing things, such as buying insurance with their purchase or signing up for recurring bills.”
Having fun with hardware is a good way to learn about the machines which soon will become our new overlords. With this pretty interesting presentation you can dive deep into what a CPU does and how it can be exploited to run code by not running it.
“Trust Analysis, i.e. determining that a system will not execute some class of computations, typically assumes that all computation is captured by an instruction trace. We show that powerful computation on x86 processors is possible without executing any CPU instructions. We demonstrate a Turing-complete execution environment driven solely by the IA32 architecture’s interrupt handling and memory translation tables, in which the processor is trapped in a series of page faults and double faults, without ever successfully dispatching any instructions. The “hard-wired” logic of handling these faults is used to perform arithmetic and logic primitives, as well as memory reads and writes. This mechanism can also perform branches and loops if the memory is set up and mapped just right. We discuss the lessons of this execution model for future trustworthy architectures.”
SDR – or Software Defined Radio is relatively cheap and fun way to dive deeper into radio communication.
“Software-defined radio (SDR) is a radio communication system where components that have been typically implemented in hardware (e.g. mixers, filters, amplifiers, modulators/demodulators, detectors, etc.) are instead implemented by means of software on a personal computer or embedded system. While the concept of SDR is not new, the rapidly evolving capabilities of digital electronics render practical many processes which used to be only theoretically possible.” (Wikipedia)
So with cheap hardware it’s possible to receive radio transmissions on all sorts of frequencies and modulations. Since everything after the actual “receiving stuff”-phase happens in software the things you can do are sort of limitless.
Now what about the relatively cheap factor? – The hardware you’re going to need to start with this is a DVB-T USB stick widely available for about 25 Euro. The important feature you’re going to look for is that it comes with a Realtek RTL2832U chip.
“The RTL2832U is a high-performance DVB-T COFDM demodulator that supports a USB 2.0 interface. The RTL2832U complies with NorDig Unified 1.0.3, D-Book 5.0, and EN300 744 (ETSI Specification). It supports 2K or 8K mode with 6, 7, and 8MHz bandwidth. Modulation parameters, e.g., code rate, and guard interval, are automatically detected.
The RTL2832U supports tuners at IF (Intermediate Frequency, 36.125MHz), low-IF (4.57MHz), or Zero-IF output using a 28.8MHz crystal, and includes FM/DAB/DAB+ Radio Support. Embedded with an advanced ADC (Analog-to-Digital Converter), the RTL2832U features high stability in portable reception.” (RealTek)
You’ll find this chip in all sorts of cheap DVB-T USB sticks like this one:
To use the hardware directly you can use open source software which comes pre-packaged with several important/widely used demodulator moduls like AM/FM. Gqrx SDR is available for all sorts of operating systems and comes with a nice user interface to control your SDR hardware.
The neat idea about SDR is that you, depending on the capabilities of your SDR hardware, are not only tuned into one specific frequency but a whole spectrum several Mhz wide. With my device I get roughly a full 2 Mhz wide spectrum out of the device allowing me to see several FM stations on one spectrum diagram and tune into them individually using the demodulators:
The above screenshot shows the OS X version of Gqrx tuned into an FM station. You can clearly see the 3 stations that I can receive in that Mhz range. One very strong signal, one very weak and one sort of in the middle. By just clicking there the SDR tool decodes this portion of the data stream / spectrum and you can listen to a FM radio station.
Of course – since those DVB-T sticks come with a wide spectrum useable – mine comes with an Elonics E4000 tuner which allows me to receive – more or less useable – 53 Mhz to 2188 Mhz (with a gap from 1095 to 1248 Mhz).
Whatever your hardware can do can be tested by using the rtl_test tool:
root@berry:~# rtl_test -t
Found 1 device(s):
0: Terratec T Stick PLUS
Using device 0: Terratec T Stick PLUS
Found Elonics E4000 tuner
Supported gain values (14): -1.0 1.5 4.0 6.5 9.0 11.5 14.0 16.5 19.0 21.5 24.0 29.0 34.0 42.0
Benchmarking E4000 PLL…
[E4K] PLL not locked for 52000000 Hz!
[E4K] PLL not locked for 2189000000 Hz!
[E4K] PLL not locked for 1095000000 Hz!
[E4K] PLL not locked for 1248000000 Hz!
E4K range: 53 to 2188 MHz
E4K L-band gap: 1095 to 1248 MHz
Interestingly when you plug the USB stick into an Raspberry Pi and you follow some instructions you can use the Raspberry Pi as an SDR server allowing you to place it on the attic while still sitting comfortably at your computer downstairs to have better reception.
If you want to upgrade your experience with more professional hardware – and in fact if you got a sender license – you can take a look at the HackRF project which currently is creating a highly sophisticated SDR hardware+software solution:
If you want to interface with the publicly available instance of the miataru server you can use the URL: http://service.miataru.com. This URL also is pre-configured with the iOS client that got recently available in the AppStore.
I started working on a Node.js project and so far it’s a quite satisfying experience. But what is Node.js?
There are a lot of things that are approached differently in Node. One of which is how you deal with code and debuggings.
I come from a world of fully integrated development environments. I had that for C#, it’s there for Java, it’s even there for Objective-C.
So it’s a bit like a toolbox you are supposed to put together yourself. And in this article I want to describe how a 2-week-beginners development environment for Node looks like. If you got anything to improve or add – go ahead, leave a comment!
GIT! I am using GitX and command line git to work with the source control. Nothing special really.
You got a lot of options here. May it be the awesome Sublime Text 2 or Eclipse or NetBeans. I chose Coda 2 since I already got it and was using it for my humble web development intermezzos. It’s awesome and if you’re on Mac you should give it a try!
Now things are getting interesting. To debug Node.js applications you have a lot of options from which a lot of them works quite good. Unfortunately I was not able to find the one IDE that provides all in one – great code editing and good debugging. So I chose to use a stand-alone debugging solution that does the trick in the best way I can think of. It’s called node-inspector and is available on all possible platforms as it seems.
Triggering and Glue
There’s only one thing left right now which is hindering the code hacking and debugging. And it’s the fact that Node.js in it’s default state does not reload changed local code files after it loaded them once. And this means: When you edit something you would have to manually restart Node.js to see the changes you just made in effect. And that’s where a little tool called Supervisor comes into play. It watches the files of your project and kills+restarts Node.js automatically for you and takes care of that bugging restart-cycle. It just works!
If course there are some more things in regards of writing tests. But this is going to be another article.
I am a long time user of Google Latitude – and since I added a Google Latitude Module to h.a.c.s. almost the whole family started using this service. It’s all about tracking your location.
“Latitude has been retired
Google Latitude was retired on August 9th, 2013. Products retired include Google Latitude in Google Maps for Android, Latitude for iPhone, the Latitude API, the public badge, the iGoogle Gadget, and the Latitude website at maps.google.com/latitude.
What does this mean for me?
You are no longer able to share your location using Latitude….”
We used it for a lot of use cases. If just to know if the other is en-route to a meeting-point or to know if someone arrived safely during a long trip. Or in terms of home automation to let the house know if you are there or somewhere else – for instance to enable or disable the house alarming system or to power up / shutdown the heating if necessary.
After the retirement of Latitude on the 9th of August all those use cases where not doable anymore. Yes there are some tools that do this and that for Location tracking. But when Google Latitude was still active it did not fullfil all use-cases I would have gotten – it was just “good enough”. Now all those subtitutes are not even close to a fraction of the use cases I would have.
Now what? Easy! If nothing works out, you gotta do it yourself!
So I started a new spare-time project I call Miataru. Weird name, eh?
“Miataru or 見当たる is Japanese and means “be found” or “to come across” and it’s meant to be a set of tools to allow the user to track locations and choose how to work with the data as well as how data is stored if at all.” (Miataru.com)
So – this should not be a replacement for anyone for Google Latitude. But the goal is to create a client+server toolset that allows you to cover a lot of use cases around location tracking and the interfacing with other software like home automation.
So expect some articles here about all the funny things and learnings about NodeJS and Objective-C / iOS development.
Some quick words to all you readers:
If you want to participate in an open source project in NodeJS and Mobile devices you’re invited to join anytime!
I’ve added Alarming to hacs a while ago and I’ve now extended the built-in SMS gateway providers with the german telekom services called “Global SMS API”.
This API is offered through the Telekom own portal called developer garden and is as easy to use as it can possibly be. You only need to set-up the account with developergarden and after less than 5 minutes you can send and receive SMS and do a lot more. They got APIs for nearly everything you possible want to do … fancy some “talk to your house”-action? Would be easy to integrate into h.a.c.s. using their Speech2Text APIs.
They have a short video showing how to set it all up:
So I’ve added the SMS-send capabilities to the hacs internal alarming system with it’s own JSON configuration file looking like this:
And this simple piece of configuration leads to SMS getting sent out as soon as – in this example – a window opens:
Before the Telekom Global SMS API I’ve used a different provider (SMS77) but since the delivery times of this provider varied like crazy (everything from 30 seconds to 5 minutes) and the provider had a lot of downtimes my thought was to give the market leader a try.
Most development projects are relying on a source code repository these days to have control over the constant changes by many team members. The source code repository is therefore the complete history of a software project.
With the great tool called “gource” you can visualize it! This for example is the project a team from Rakuten Germany (where I work) worked on for the last couple of months:
Obviously it’s impossible for Apple to fix that quite annoying bug in their operating system that leads to double/tripple/… program entries in the “Open with…” menu. Everytime an application is updated it adds a new entry but does not remove the old one.
This makes your open-width menu look like this:
To fix this you need to run a simple command in your terminal.app:
/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user;killall Finder
This simple command will kill the double/tripple/… entries and restarts your finder.app to make the change visible. Your “Open with…” menu should now only show singular entries per application:
“Hyper-lapse photography – a technique combining time-lapse and sweeping camera movements typically focused on a point-of-interest – has been a growing trend on video sites. It’s not hard to find stunning examples on Vimeo. Creating them requires precision and many hours stitching together photos taken from carefully mapped locations. We aimed at making the process simpler by using Google Street View as an aid, but quickly discovered that it could be used as the source material. It worked so well, we decided to design a very usable UI around our engine and release Google Street View Hyperlapse.“
Die verfügbaren IPv4 Adressen neigen sich dem Ende und IPv6 wird kommen. Da gibt es keinen Zweifel! Dieses Weblog beispielsweise ist seit über zwei Jahren nativ über IPv6 erreichbar. Nun wird es mit jedem Monat der ins Land geht immer ‘brenzliger’ und dementsprechend wichtig ist der Schritt unter anderem auch für die öffentliche Verwaltung. Interessante Einblicke gibt dieses umfangreiche Dokument:
“Seit den Anfangstagen des Internets wird zur Übertragung der Daten das Internet Protokoll in der Version 4 (IPv4) verwendet. Heute wird dieses Protokoll überall verwendet auch in den internen Netzen von Behörden und Organisationen. Das Internet und alle Netze, welche IPv4 heute verwenden, stehen vor einem tiefgreifenden technischen Wandel, denn es ist zwingend für alle zum Nachfolger IPv6 zu wechseln.
Auf die oft gestellte Frage, welche wesentlichen Faktoren eine Migration zu IPv6 vorantreiben, gibt es zwei zentrale Antworten:
Es gibt einen Migrationszwang der auf die jetzt schon (in Asien) nicht mehr verfügbaren IPv4-Adressen zurückführen ist.
Mit dem steigenden Adressbedarf für alle Klein- und Großgeräte, vom Sensor über Smartphones bis zur Waschmaschine, die über IP-Netze kommunizieren müssen verschärft sich das Problem der zur Neige gegangenen IPv4-Adressräume. Das Zusammenkommen beider Faktoren beschleunigt den Antrieb zur IPv6-Migration.
Es wird in Zukunft viele Geräte geben, die nur noch über eine IPv6-Adresse anstatt einer IPv4-Adresse verfügen werden und nur über diese erreichbar sind. Schon heute ist bei den aktuellsten Betriebssystemversionen IPv6 nicht mehr ohne Einschränkungen deaktivierbar. Restliche IPv4-Adressen wird man bei Providern gegen entsprechende Gebühren noch mieten können. Bei einem Providerwechsel im Kontext einer Neuausschreibung von Dienstleistungen wird man diese jedoch nicht mehr ‘mitnehmen’ können. Damit bedeutet eine Migration zu IPv6 nicht nur die garantierte Verfügbarkeit ausreichend vieler IP-Adressen, sondern stellt auch die Erreichbarkeit eigener Dienstleistungen für die Zukunft sicher ohne von einem Anbieter abhängig zu sein.”
Back then I already wrote about the Panic status board which gives a great looking example of a status display. Now there is a software from the company Panic which offers anyone the ability to create such a status board. It’s for iOS and looks awesome!