Aug 202013
 

Die von uns in unseren Raspberry Pi Kits gebündelten Logilink WL0084B v2.0 sind für Raspbian und Raspbmc getestet, und funktionieren “out of the box”. Wir stellen in diesem Blog-Eintrag vor, wie dieser nano WiFi Adapter und andere kompatible Adapter unter Raspbmc für das Funknetzwerk eingestellt werden können.

(Anmerkung: für den TP-Link Wireless N Nano USB Adapter TL-WN725N entwickeln wir aktuell ein Paket, mit dem dieser WLAN Stick ebenfalls unproblematisch einzusetzen sein sollte. In unserem letzten Test funktionierte dieser Stick leider nicht out-of-the box.)

Einrichten

Wir gehen hier von einer “virgin Raspbmc” Installation mit Stand 20. August 2013 aus, an der noch keine Einstellungen für das Funknetzwerk getroffen wurden.

Rufen Sie die Raspbmc Settings (unter dem Menüpunkt Programme) per Klick auf:

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Achtung: die Raspbmc Settings benötigen zum Starten in älteren Versionen eine verbundene LAN-Netzwerkverbindung! In unserem aktuellen Test lassen sich die Settings auch ohne LAN Verbindung öffnen.

Öffnen Sie den Reiter “Network Configuration”

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Klicken Sie mit der Maus auf die Pfeile neben Network Mode nach oben oder nach unten, um “Wireless (WiFi) Network einzustellen”

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Scrollen Sie mit Hilfe der Leiste rechts nach unten, und stellen Sie die SSID Ihres Netzwerkes durch Klick auf die entsprechende Zeile ein:

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Es öffnet sich ein Dialog, in dem Sie die SSID einstellen können.

Stellen Sie jetzt Ihren WiFi KEY ein durch Klick auf die entsprechende Zeile.

Bitte beachten Sie: bei einer “normalen” Raspbmc Installation ist eine englische Tastaturbelegung trotz der Sprachauswahl “Deutsch” am Anfang weiter vorhanden. Das führt dazu, dass beispielsweise “z” und “y” vertauscht sind. Falls Ihr WiFI Key solche Zeichen enthält, könnte ein Verbindungsproblem daran liegen.

Wir haben in diesem Artikel beschrieben wie Sie die Sprache für die Tastatur umstellen (Konsolenkentnisse Voraussetzung). Alternativ können Sie auch unser Movie Kit kaufen, in dem diese Voreinstellung bereits für Sie getroffen worden ist. Im Movie Kit sind neben vielen praktischen Komponenten auch MPEG-2 und VC-1 Schlüssel mit enthalten.

Passen Sie ggf. auch den WiFi Security Modus an. WPA/WPA2 sollte in modernen Netzwerken der Standard sein, und kann daher meistens unverändert bleiben.

Sobald Sie fertig sind, aktivieren Sie bitte den Radio Button “Update Now”, und drücken auf OK:

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Das System zeigt Ihnen an, dass die Einstellungen übernommen und angewendet wurden.

Jetzt können Sie Ihr LAN Kabel abziehen (falls es noch angeschlossen ist), und die Verbindung sollte über den WiFi Adapter funktionieren. Es ist kein Neustart nötig.

IP Adresse & Fehlersuche

Im eingebauten Systeminfo Menü können Sie sich eine Übersicht über den Status von Raspbmc geben lassen, unter anderem auch die IP Adresse:

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Durch Klick auf “Netzwerk” erhalten Sie weiterführende Informationen, z.B. zum aktuell verwendeten DNS Server, und ob das System eine Verbindung zum Internet hat:

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Dec 072012
 

As has frequently been written elsewhere, the main source of problems for the Raspberry Pi systems is the power supply. I would even go as far as saying: before debugging anything else, measure the voltage!

On the Raspberry PI two test points are located. TP1 and TP2. With a voltmeter you can measure the voltage between them. According to the Raspberry Pi handbook by Eben Umpton (page 49) it should be between 4,8 V and 5 V.

I am testing several different power supply units (mostly USB chargers …), and will be offering only know good units in the shop. By buying a known good power unit you can avoid the following

Problems / symptoms of low voltage / weak power supplies

  • corrupted SDHC cards (even quality cards will get corrupted / dismounted – eventually the filesystem will not be able to restore itself)
  • frequent USB connects and disconnects
  • some distributions, i.e. Raspbmc / OpenELEC not working correctly / not recognizing mouse and keyboard, while others (Raspbian Wheezy) will work just fine …
  • keyboard (on a powered hub!) working, while mouse (on the same hub) does NOT work

Causes of low voltage

  • weak power supply
  • power supply requires negotiation for more than 500 mA, which the Raspberry PI does not do (Raspberry Pi handbook)
  • greedy USB peripherals attached to the pi, for example illuminated keyboard
  • using rechargeable batteries which are not freshly charged (I see 4,44 V with batteries which are giving 5 + V without load)

Even if your power supply states that it will provide up to 1 A, this will not necassarily be with 4,8 – 5 V – many supplies I’ve tried show this behaviour.

According to Gert van Loo, whom I met at the fair, the Raspberry Pi will take at maximum 1 – 1,5 A, depending on the ambient temperature, before the fuses start kicking in. As such, there will be no point in trying to attach a 4 A powersupply, for instance, in order to provide power to the USB ports.

Known good power supplies

The following adapters or compatible, thoroughly tested, models will be available in our shop:

goobay Model 42438 car adapter (12 V -> 5 V)

Provides between 4,94 V and 5,10 V in our tests. It has a micro USB plug.

D-Parts Mobilphon & Zubehör Gmbh (DP-LGS) Model AC0122-051000 (230 V -> 5 V)

Provides 4,93 V in idle mode. It has a micro USB plug.

Known “bad” power supplies

The power drawn from the Raspi in our tests has been measured at roughly 500 mA – well below the 1 A level specified by the vendors of the following adapters:

LogiLink USB Travel Charger Combo Kit PA0008A v2.0

This (white) mains power supply is quite unstable and NOT suitable to power the Raspberry Pi. It will provide about 4,3 – 4,6 V under load / in idle mode, at about 0,5 A of current being drawn. We’ve tested two supplies of this series. Another downside: the USB plug will not have a good, secure fit in it’s outlet.

We’ve also seen huge oscillations in the voltage with it – ranging from about 3,9 V to 5,1 V.

All in all, the Raspi will display the known symptoms (see above).

The car adapter (which converts 12 V to 5 V) also runs at 4,74 V with the Raspberry Pi in idle moad (no load).

The package states that it will provide 1 A. Maybe. But probably not at 5 V.

 

FRIWO FW7713 (230 V -> 5 V)

This adapter performs better than the LogiLink one, still voltage levels drop below the magical 4,8 V level. Under load we have measured 4,68 V / 4,62 V for instance. (With a nominal 460 mA load from the Raspi).

The USB plug has a more secure fit than in the Logilink counterpart (see above).

Nov 112012
 

This is the first post ever on this blog. So, first of all – a hearty welcome! We hope you have a pleasant stay.

What’s this post about?

Say, you’ve got a Raspberry Pi and two SDHC cards – one is already set up with Raspbian, you can boot into it, and get your Pi online. The other one is empty – and you want to install Raspbmc on it.

There are graphical installers, of course, and other “easy” ways to do it from your main computer, assuming you have one.

But what, if not? Or if you simply want to use a Raspberry Pi to bootstrap another Raspberry Pi?

Well – it’s pretty easy! And of course this procedure can also be used to bootstrap all other known systems for the Pi out there!.

Prerequisites

  • Raspberry Pi, connected to the Internet, booting into Raspbian or another distribution with command line access
  • SDHC card reader
  • second SDHC card
  • enough space on the first SDHC card to download and decompress the image you intend to use

Instructions

We assume you run as normal user (pi), thus you need to prefix some commands with sudo

  • Attach your SD reader with the second SDHC card inserted, on which you want to install Raspbmc. The SD reader should be attached to a powered hub.

Attention!!! All data on the second SDHC will be overwritten by this installation procedure. If in doubt, do not proceed!

Attention 2: If you attach your SD reader directly to the Raspberry Pi, it may become unstable and crash during the writing process (as result of a power deficit during writing to the SD card). Even if your SDHC can be readable just fine, writing to it may use more power and thus lead to unpredictable results.

  • Log into your Raspberry Pi shell
  • Download your image to the /tmp directory using wget. We will use the Raspbian network install (to save space on the first SDHC card).

cd /tmp
wget http://download.raspbmc.com/downloads/bin/ramdistribution/installer.img.gz

  • Unpack it

gunzip installer.img.gz

  • Install dcfldd (Note: if you do not want to install dcfldd just use dd instead – dcfldd displays a progress message)

sudo aptitude install dcfldd

  • Check that your SDHC card is being recognized properly. Most probably, you will recognize it by its size

sudo fdisk -l

image

The SDHC we are going to write to is /dev/sda – I identified it by its size, 16 GB. In the screenshot above you can also see the partitions in each drive.

Attention: Please ensure that you are going to write the the correct target!! Once again, the data on the target WILL be lost. If in doubt, please shutdown your Raspberry Pi and remove all unneeded storage devices – only leave the internal SDHC card and the SDHC you are going to bootstrap.

Attention: Before proceeding, check that you really do NOT need the data on the respective drive anymore. If in doubt, plug it into another machine, for instance an Ubuntu desktop machine to review it’s contents. Please note, that Windows will not recognize Linux partitions.

The other “disk” here ( /dev/mmcblk0) is the SDHC card inserted into the Raspberry Pi directly, from which it boots. As you see, I’ve used a 4 GB card, here.

  • check that no partitions from your target SDHC card are mounted:

mount -l

image

You have to look for /dev/sdaxx here (the device we are going to write to in a second). In this first screenshot, no partitions from this drive are mounted.

image

In this screenshot, we have /dev/sda1 (the first partition) mounted on /mnt/my_mountpoint. If that is the case, you have to unmount it:

sudo umount /dev/sda1

Change the device name accordingly to the partition(s) mounted in your setup. Also recheck using mount -l whether the unmount was successfull.

Writing to the SD Card

  • Now we can write the image to the new SDHC card:

dcfldd bs=4M if=/tmp/installer.img of=/dev/sda

Assuming your image’s name is installer.img, and your device name (the SDHC card) is /dev/sda. Please change accordingly!! The block size 4M should be OK – if it does not work for you (errors …), try 1M instead.

This will take a while – once it is finished, it should display something like this:

root@raspberrypi:/tmp# dcfldd bs=4M if=/tmp/installer.img of=/dev/sda

18+1 records in
18+1 records out
root@raspberrypi:/tmp# ls

Booting into Raspbmc

If you followed the instructions, you should be all set to boot into Raspbmc. Turn off your Raspberry Pi (using halt for instance), switch the SD cards and turn it back on again!

The network setup of Raspbmc will try to connect to the Internet – ensure that the LAN is attached to a DHCP router connected to the Internet, and download the latest release. It will show you a couple of dialogs during the setup, but mostly it is a very straighforward thing. Go grab a cup of coffee, like the installer recommends.

raspbmc-network-installer

Raspbmc will by default install and expand to the entire SD card.

The device will then reboot itself – and you can start to enjoy Raspbmc!

raspbmc-on-Raspberry-Pi

Raspbmc even supports GrooveShark Anywhere:

raspbmc-Grooveshark-Anywhere

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