how to get mobile Internet (3G / LTE) in Japan

Posted on by Daniel Kirstenpfad

If you visit Japan the next time and you want to get perfectly good Internet access while there on your mobile phone I can recommend the b-mobile offer. On my last stay in Japan (May 2014) I tried their service for the first time and I was not let down.

They give you two options: The 1 GB prepaid option gives you 1 GB as fast as possible. The 14days prepaid gives you 14 days of limited speed coverage (300kbps).

Bildschirmfoto 2014-05-18 um 18.04.18

I went for the 14 days prepaid option knowing that I might get some usage depending on where I go. The 300kbps where faster than I thought – at no given time I experienced any speed problems. The coverage was awesome since it just dialed into NTT Docoms 3G/LTE network.

For just under € 30 this is an awesome option for any traveller. Even better: You can pick it up at the Airport or you can have it delivered to your hotel! We tried both and it worked both as expected. Fast delivery, perfect service!

Source: http://www.bmobile.ne.jp/english/product.html

Need to do Load Tests? Try Tsung!

Posted on by Daniel Kirstenpfad

Tsung is an open-source multi-protocol distributed load testing tool

It can be used to stress HTTP, WebDAV, SOAP, PostgreSQL, MySQL, LDAP and Jabber/XMPP servers. Tsung is a free software released under the GPLv2 license.

The purpose of Tsung is to simulate users in order to test the scalability and performance of IP based client/server applications. You can use it to do load and stress testing of your servers. Many protocols have been implemented and tested, and it can be easily extended.

It can be distributed on several client machines and is able to simulate hundreds of thousands of virtual users concurrently (or even millions if you have enough hardware …).

Source 1: http://tsung.erlang-projects.org/

MOSH (Mobile Shell) – fixing SSH for everyone

Posted on by Daniel Kirstenpfad

How many times did you experience a connection loss on your terminal window in the last week? Yeah I know – like everytime you close the lid of your notebook and move to a different place. So like a dozen times every day.

And everytime you reconnect to your servers and you use things like screen to keep your terminals open and your programs running while you’re disconnected.

On the other hand – did you ever curse the internet gods while you tried to do a very important check or bugfix to a machine whilst on a train or mobile roaming network? It’s not what I would call fun-times. When there are no constant disconnects the lag is just infuriating. MOSH also solves this since it’s predicting and responding way faster then vanilla SSH. Your terminal becomes useable again!

So there’s now MOSH to the rescue:

Remote terminal application that allows roaming, supports intermittent connectivity, and provides intelligent local echo and line editing of user keystrokes.
Mosh is a replacement for SSH. It’s more robust and responsive, especially over Wi-Fi, cellular, and long-distance links.
Mosh is free software, available for GNU/Linux, FreeBSD, Solaris, Mac OS X, and Android.

[youtube]http://www.youtube.com/watch?v=XsIxNYl0oyU[/youtube]

Install it on your servers and your clients and never lose a connection again.

Source 1: http://www.gnu.org/software/screen/
Source 2: http://mosh.mit.edu

IPv6 native root server has problems with OpenFire Jabber / XMPP Server to Server

Posted on by Daniel Kirstenpfad

I was setting up a new root-server machine and went for the Debian 7 minimal set-up. Thankfully the root-server provider I am using (hetzner) is connected with IPv4 and IPv6 natively. Awesome stuff!

If you’re using an IPv6 native set-up these days you STILL have to be cautious about possible side-effects with software having bugs and not knowing how to deal with these ginormous ip adresses.

So there’s a well known Jabber / XMPP server that I am using for some years now without any issues. I was even using it on native IPv6 connected machines earlier.

But with the fresh and clean set-up of Debian 7 and IPv6 by the hoster several problems started bubbling up.

1: the ‘there can only be one ipv*’ problem

Turns out that the debian team decided to set a system setting by default that lets IPv6 aware applications bind to IPv6 only. Good thing, you can disable it by adding this to your sysctl.conf:

net.ipv6.bindv6only=0

2: the ‘who resolves first is right’ problem

When you get a IPv6 native machine it might have a resolv.conf consisting of IPv4 and IPv6 name servers. And don’t worry: Everything is going to be all-right as long as the software you’re planning to use is perfectly capably dealing with the answers of both types of servers. The IPv4 ones will default to the A records, the IPv6 ones to the AAAA record.

Now there’s OpenFire. A stable and easy to use XMPP / Jabber server implementation. It’s based upon Java and I am running it with Java 7 on my Debian machine.

Unfortunately in the current 3.9.1 version of OpenFire there’s a bug that leads to Server-to-Server XMPP connections not working when they resolv to IPv6. So for example your Google-Talk contacts won’t work at all.

The bug itself is rather stupid: Seems that OpenFire expects an IPv4 adress from the DNS lookup and crashes on an IPv6 adress.

The solution is as easy as the bug is stupid: Remove the IPv6 defaulting nameservers from your resolv.conf.

# nameserver config
nameserver 2xx.xxx.yyy.99
nameserver 2xx.xxx.yyy.100
nameserver 2xx.xxx.yyy.98
nameserver 8.8.8.8
nameserver 8.8.4.4
#nameserver 2axx:yyy:0:zzzz::add:9898
#nameserver 2axx:yyy:0:zzzz::add:9999
#nameserver 2axx:yyy:0:zzzz::add:1010

Source 1: defaulting to net.ipv6.bindv6only=1
Source 2: http://community.igniterealtime.org/thread/51902

The Data Visualisation Catalogue

Posted on by Daniel Kirstenpfad

“The Data Visualisation Catalogue is currently an on-going project developed by Severino Ribecca.

Originally, this project was a way for me to develop my own knowledge of data visualisation and create a reference tool for me to use in the future for my own work. However, I thought it would also be useful tool to not only other designers, but also anyone in a field that requires the use of data visualisation regularly (economists, scientists, statisticians etc).

Although there have been a few attempts in the past to catalogue some of the established data visualisation methods, there is no website that is really comprehensive, detailed or helps you decide the right method for your needs.

I will be adding in new visualisation methods, bit-by-bit, as I research each method to find the best way to explain how it works and what it is best suited for.”

Bildschirmfoto 2014-03-29 um 13.11.59

Source 1: http://datavizcatalogue.com/

Brackets: a multi-platform editor written in javascript – including NodeJS

Posted on by Daniel Kirstenpfad

“Brackets is an open source code editor for web designers and front-end developers.”

hero

On the first tries it’s an awesome thing to have all that JavaScript debugging, Live HTML editing and what-not in one place. Give it a spin.

[youtube]https://www.youtube.com/watch?v=T6d5C3rLeFY[/youtube]

Source 1: http://brackets.io/

weave your net of things that have internet…ehm – internet of things

Posted on by Daniel Kirstenpfad

node-red-screenshot

“The internet of things” is a buzzword used more and more. It means that things around you are connected to the (inter)network and therefore can talk to each other and, when combined, offer fantastic new opportunities.

Yeah right.

So NodeRed is a NodeJS based toolset that allows you to create so called “flows” (see picture above). Those flows determine what reacts and happens when things happen. Fantastic, told you!

Source 1: http://nodered.org/
Source 2: http://en.wikipedia.org/wiki/Internet_of_ThingsSource 3: http://nodejs.org/

How to fix a mono CS0589 Internal compiler error during parsingSystem.FormatException error on the RaspberryPi

Posted on by Daniel Kirstenpfad

When you want to compile some C# code using MONO on Linux on your RaspberryPi and you encounter this strange error message:

error CS0589: Internal compiler error during parsingSystem.FormatException

You need to do:

  1. Update your Debian by running:

    sudo apt-get upgrade
    sudo apt-get update

  2. Upgrade your RaspberryPi firmware:

    sudo rpi-update

  3. Reboot your RaspberryPi
  4. Retry compiling – should work now.

The reason for Mono to crap out like above: Previous Mono versions and RaspberryPi firmwares where not compatible due to one side using HardFP and the other not.

ZFS Tutorial

Posted on by Daniel Kirstenpfad

“ZFS is really the final word in filesystems. With a feature set longer than this tutorial, it can take a while to master. You can set many more options per dataset, enable disk usage quotes and much more. Once you’ve used it and seen the benefits, you’ll probably never want to use anything else. Hopefully this has been helpful to get you on your way to becoming a FreeBSD ZFS master.”

Source: http://www.bsdnow.tv/tutorials/zfs

I give you: the SONOS Audiobook / Podcast Auto Bookmarker – never lose your Listening Progress again…

Posted on by Daniel Kirstenpfad

Since the SONOS system I’ve bought turned out to be highly hackable I’ve spent some quality-time this weekend fixing the worst downside I’ve found so far that the SONOS system had for me

I am listening to a lot of Podcasts and Audiobooks. And it turns out that those two Genre are not particularly good supported by SONOS. When you’re listening to a 4 hour podcast and you stop it to play a song in between (since you stretch the listening of that podcast to several days) the next time you start that 4 hour podcast the SONOS system did not remember the position that you stopped at the last time and restarts the podcast from the beginning.

If you did not remember where you left of the last time, you’re lost. The same goes for Audiobooks.

Now this is the first feature I am teaching my SONOS system. And I am opensourcing it so you can do it as well.

SONOS Auto Bookmark Tool

Everything you need can be run on a RaspberryPi:

  1. You need NodeJS and node-sonos-http-api installed and running.
  2. You need MONO and sonos-auto-bookmarker (change the configuration.json file in bin/Debug after you xbuilded the .sln file)

Now the Auto Bookmarker Tool will, with the help of the sonos-http-api, monitor your household and whenever something longer than 10 minutes is played and stopped it bookmarks the last played position. Whenever you restart that track it will then seek to the last known position automatically.

[youtube]https://www.youtube.com/watch?v=Eqk3SyNv8sE[/youtube]

Source 1: https://github.com/bietiekay/sonos-auto-bookmarker

Let the SONOS hacking begin!

Posted on by Daniel Kirstenpfad

I always wanted a networked multi-room audio solution as you can easily see here and here and here and here. Now it seems I’ve finally found something that integrates very well into our music listening habits and our infrastructure. And on top of that it turned out to be highly hackable.

I’ve went with SONOS for that multi-room solution. After trying two speakers for two rooms I’ve invested the budget into the full-house solution (not all speakers on below picture). And finally everything is as I always wanted.

Be warned: If you buy one speaker, you will definitly buy more.

IMG_0367

So what’s in those boxes? Besides beautiful and high-quality speakers there’s a 250 Mhz linux powered computer inside each speaker. It got 64Mbytes of memory and wireless adapters to span it’s own wireless mesh network (hidden by default).

Each speaker on it’s own can be controlled and accessed through the SONOS controller applications (Windows/Mac/iOS/Android) or through several tools that open up new possibilities.

Screen Shot 2014-03-22 at 17.52.10

There will be more articles coming on the topic of hacking SONOS, adding functionality and using it for things not officially planned for by the manufacturer. Joy!

Update:

Source 1: http://splok.org/sonos_interface

How to install NodeJS and NPM on the RaspberryPi without getting “Illegal Instruction” error messages

Posted on by Daniel Kirstenpfad

I tried a couple of times to compile NodeJS on the RaspberryPi and failed miserably. It not only takes ages to compile NodeJS on the Pi. After the successful compile and install run most of the time running it just results in an error message “Illegal Instruction” or “Ungültiger Maschinencode”.

Now there’s a pretty easy way to do that on your own. Run these commands:

wget http://node-arm.herokuapp.com/node_latest_armhf.deb

After the download is finished successfully you can install it by running this as root:

sudo dpkg -i node_latest_armhf.deb

This will have installed a relatively new NodeJS built as well as NPM on your RaspberryPi. Don’t panic when NPM is slower than you would expect… just be patient.

Enjoy!

On-Screen OCR – helps you when all you get is an image…

Posted on by Daniel Kirstenpfad

“You want to extract one paragraph of text from a pdf your coworker sent you? One quote from your professor’s presentation? A couple of code lines from this tutorial clip on your favourite movie platform? It’s just one hotkeypress away. OCR everything on the fly.

Condense is the product of many frustating years of using overly complicated OCR software. “Take a screenshot, boot up your OCR suite, select the area you want to extract, select an output file…” Oftentimes typing out is faster than walking through this procedure.”

[youtube]http://www.youtube.com/watch?v=hLqVLplAD8w[/youtube]

Source 1: http://www.condenseapp.com/

document your REST interfaces with style: Swagger

Posted on by Daniel Kirstenpfad

“Swagger is a specification and complete framework implementation for describing, producing, consuming, and visualizing RESTful web services. The overarching goal of Swagger is to enable client and documentation systems to update at the same pace as the server. The documentation of methods, parameters, and models are tightly integrated into the server code, allowing APIs to always stay in sync. With Swagger, deploying managing, and using powerful APIs has never been easier.”

Bildschirmfoto 2014-03-15 um 22.35.09

Source 1: https://helloreverb.com/developers/swagger
Source 2: https://github.com/wordnik/swagger-core
Source 3: http://petstore.swagger.wordnik.com/#!/pet

miataru can embed your location into any website now!

Posted on by Daniel Kirstenpfad

An exciting new feature has been added to the Miataru service! It’s now possible to embed the location of a device into any website. Here’s an example:

It’s a pretty easy process. When your device is available on the standard public miataru service you only have to embed an iFrame into the website. Just like this:

<iframe width=”320″ scrolling=”no” height=”240″ frameborder=”0″ src=”http://miataru.com/client/embed.html#BF0160F5-4138-402C-A5F0-DEB1AA1F4216;Demo Device”></iframe>

Source 1: http://miataru.com/client/#BF0160F5-4138-402C-A5F0-DEB1AA1F4216
Source 2: https://github.com/miataru/miataru-webclient

GraphHopper: blazingly fast routes with OpenStreetMap

Posted on by Daniel Kirstenpfad

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.”

GraphHopper
Source 1: http://graphhopper.com