Getting Started With Raspberry Pi

• Question: the other problem with using a imac as a display is; imacs only take input signals from thunderbolt devices, at least de new ones, if you only have a displayport signal the imac won't recognize it and won't display anything... kinda uncool, i would have loved to use my imac as a display for my raspberry - hotdawgz
• Answer:

  Indeed, that is true on Thunderbolt equipped iMacs (Mid 2011 and Late 2012 models), the 27” Mid 2010 and Late 2009 models used DisplayPort.

  Thanks for the correction!

• Question: How do I configure a keyboard? - c0wpoke
• Answer:

  Simply run:

  sudo raspi-config

  and use the configuration utility to set your keyboard layout.

• Question: use imac as monitor - molto-amore
• Answer:

  Short answer: no.

  Long answer: The Raspberry Pi supports HDMI and composite video (RCA) and sends these video signals via the respective port. When in target display mode the iMac requires a DisplayPort signal to work as a monitor, which of course the Raspberry Pi cannot output through it’s HDMI connector. HDMI/DisplayPort adapters can be purchased, but they would need to convert the signal to work with the iMac due to the two different standards.

  You may wonder why such adapters exist? Well, a DisplayPort (or Thunderbolt) connector on a Mac can output an HDMI signal allowing you to connect a Mac to a TV, the adapter allows such connections to be made.

• Question: how do I retrieve or reset a forgotten user id & password? - georgesuar
• Answer:

  Assuming you have automatic login enabled:

  When you’re booted you’ll either be at the command prompt already, if you’re in the GUI open a Terminal window. Simply type “sudo passwd username” where username is your username. You can now reset the password for that user account.

  The default username is “pi”, if you’e using a different username find the username by entering “cat /etc/passwd |grep "/home" |cut -d: -f1” to get a list of usernames (Hint: It will be what you use to login!). From LinuxQuestions.org.

  ---

  If you can’t login at all:

  You would need to use the root user to login and change your user password. In Raspbian it appears as though the root password is not set, therefore you would not be able to login as root and reset the user’s password. If you’ve setup any ssh access and the password was set to be remembered, try the above command in an ssh session.

How to Safely Shutdown or Reboot Your Raspberry Pi

Title says it all, but there’s a bit more useful information too. Personally, I’ve always used “sudo halt”.

Learn Python The Hard Way

Finally time to start learning Python. I’ve done a fair amount of programming as a hobby and in education and am competent in Objective-C, and familiar with Java and PHP (and some others). All the Raspberry Pi stuff seems to favour Python, so I’ve taken the plunge and am using this book to learn. I’ll see how I get on and post a bit more on my experience with the book in a week or two.

Something I had overlooked in my previous entries was the lack of any guide to SSH (Secure Shell). This basically enables you to access a computer (including, of course, your Raspberry Pi) using a command line interface on another computer connected via a network - so like running the Terminal application directly on your Pi, but on another computer. This is very useful if you’re running your machine without a screen but need administer it without using VNC.

If you’ve installed Raspbian (and if you’re a beginner like me, I highly recommend you do) you’re given the option to switch this on the first boot up. If you didn’t, you can start the SSH service by entering the following into the Terminal, the reboot your machine:

sudo mv /boot/boot_enable_ssh.rc /boot/boot.rc
reboot 

With the SSH service now running, you need the Raspberry Pi’s IP address to connect. Enter “ip addr show” and your IP address should be on the last line after the word “inet” (see here for more details).

Next you need to connect to your Raspberry Pi using an SSH client. 

• Unix/Linux users: I’m surprised you’re reading this guide, you probably know what to do. :-)
• Mac users: Terminal is in your Utilities folder, in Finder select Go from the menu bar, locate it in Launch Pad or just use Spotlight.
• Windows users: A quick Google search revealed a free SSH client called PuTTY. You are probably done here, I’m not familiar with Windows clients but will try and update this post within a couple of days with more info for Windows users.

With your client open and ready to go, connect to your Raspberry Pi. The following assumes you’re using the default username “pi”. Enter:

ssh pi@xxx.xxx.xxx.xxx (where xxx.xxx.xxx.xxx is your Raspberry Pi’s IP address)
Then enter your password - the default is “raspberry”. 

You should now see a different prompt, “pi@raspbmc:~$”, and you’re ready to enter commands. Type “ls” to list the files in the current directory. Type in any other commands you would in a regular Terminal window, such as in any of the guides on this Tumblr. When you’re done, just type “exit” and you’ll return to the normal prompt, such as “compname:~ username$”

Notes:

• On Raspbmc I found I had to go through an initial configuration the first time I connected - choosing locale, etc - which is all possible using the SSH session.
• I created this post in preparation for a lengthy one on Raspbmc which will require some SSH-ing.  I hope to publish the article within the next week.

Eager to improve the performance of my Raspberry Pi, I installed the Raspbain-based SD card image today and have tested the tips/guides on this tumblr and all work as expected. I hope to continue to add more within the next week or so.

If you’re planning on using your Raspberry Pi as an appliance, you’ll want it to automatically login and load LXDE (the GUI). You may also want to do this if you are just tinkering around with the Raspberry Pi (as I am at the moment) and are using it without a monitor using a VNC server. 

This eLinux Wiki guide explains how to do it, but if you want to start your VNC server instead, instead of adding startx to the bottom of the /etc/profile file, add the command you use to start your VNC server, e.g. “vncserver :1 -geometry 1024x728 -depth 24”.

EDIT: eLinix Wiki updated their entry, the above will no longer work. This is a better way.

Another post for Mac users. If you’ve followed my previous post to setup Avahi for AFP auto discovery, you might want to do the same for VNC.

To do this, add a new service under /etc/avahi/services. Using Terminal:

1. Run “sudo nano /etc/avahi/services/rfb.service”
2. Enter the following:
   <?xml version="1.0" standalone='no'?>
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
  <name replace-wildcards="yes">%h</name>
  <service>
    <type>_rfb._tcp</type>
    <port>5901</port>
  </service>
</service-group>
3. Under the <port> element in step three, ensure you enter the correct port number that you chose when starting your VNC server .
4. Press ctrl and x to exit, then y to save and press return after confirming the file location
5. If your Mac doesn’t pick it up within a view minutes, restart the avahi service: “sudo /etc/init.d/avahi.deamon restart”

You should now see a “Share Screen…” button when you select your Raspberry Pi in the Finder side bar. Click this and the Screen Sharing app will open, enter your VNC password (leave the username blank). Other VNC software should be able to discover it also, though I’ve only tested it on Mocha VNC for iPad.

Strangely, the Apple Remote Desktop app still does not discover my VNC server using bonjour. I’ll update this post if I find out why.