Configure WIFI on Raspbian before the first boot

Usually when I prepare a Raspberry for a new project or just want set up a new operation system I configured the network with attached screen and keyboard. Sometimes this is not possible and the WIFI needs to be configured before the first boot of the Pi.

The actual Raspbian distribution Jessie released on May 27 216 (NOT the lite version) or newer brings a cool feature to preconfigure the WIFI settings. A keyboard and a screen aren't necessary to bring a Raspberry Pi with Raspbian to life.

Configuration on Windows

1. download the Raspbian image on RapsberryPi.org and extract it
2. if you don't have download the Win32DiskImager to copy the image to the SD card
3. insert the SD card in your card reader (micro SD cards with adapter, start the Win32Diskimager (it will ask to run as Administrator), and select the extracted image file (from 1)
   
4. click "Write" to start the transfer of the image to the SD card 
5. when the process is finished successfully, you should see a part of the SD card in Windows Explorer
   
6. right click into the SD card folder and create a new text-file with the name wpa_supplicant.conf
7. open the file (if possible with Textpad or Notepad++) copy the following text into the file, ensure the bold parts are changed to your WIFI, the quote marks are necessary
   
   
   update_config=1
   ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
   network={
       ssid="testwifi"
       psk="testpassword"   
   }
   
   
8. save the file, move the SD card from your computer to the Raspberry and start it 

During the first boot of Raspbian, the file wpa_supplicant.conf will be moved into the folder /etc/wpa_supplicant/ for future starts the WIFI credentials will be in the right place and the Raspberry should be able to connect to the WIFI. The file will be not longer accessible under Windows. 

Configuration on Linux

1.  download the Raspbian image on RapsberryPi.org and extract it
2. before inserting the SD card, check the attached devices with this command:
   
   
   df -h
   
   
3. then insert the SD card and repeat the command after a few seconds
   
   
   df -h
   
   in the output you should find a line like
   
   
   /dev/mmcblk0p1
   
   or
   
   
   /dev/sdd1
   
   okay in this example I will use "mmcblk0p1".
4. With the command:
   
   
   mount
   
   you need to check if the SD card is mounted somewhere. If so, unmount the SD card with
   
   
   sudo umount /mnt/sdcrd
   
   
5. Because df shows the partition and we want to copy the image file to the device, the name of the device in the copy command will be /dev/mmcblk0 or /dev/ssd 
6. when the device name of the SD card is known, the image file can be copied there. the command is:
   
   
   dd bs=4M if=2016-05-27-raspbian-jessie.img of=/dev/mmcblk0
7. after the successful copy to the SD card, the card can be removed and reinserted. There will be a check for the partitions again
   
   
   df -h
   
   in the output you should find again the same /dev/mmcblk0p1device with the command
   
   
   mount
   
   you will see the mountpoint of the SD card (in this example should be /mnt/sdcrd) 
8. in this folder should be files like
   
   
   bcm2708-rpi-b.dtb
   bcm2708-rpi-b-plus.dtb
   bcm2708-rpi-cm.dtb
   bcm2708-rpi-2-b.dtb
   bcm2708-rpi-3-b.dtb
   bootcode.bin
   cmdline.txt
   config.txt
   ...
9. with the command (change in the command mywifi to your SSID and mypassword to the password of your WIFI)
   
   
   sudo wpa_passphrase mywifi mypassword >> mnt/sdcrd/wpa_supplicant.conf
   
   you will create a file wpa_supplicant.conf in this folder
10. now the SD card can be unmounted
    
    
    sudo umount /mnt/sdcrd
    
    the card can be removed and inserted in the Raspberry. 

While starting the Raspberry the first time, the file wpa_supplicant.conf will be moved to it's usual location in /etc/wpa_supplicant. The Pi will connect with the configured WIFI during boot and you can use SSH to connect to the Raspberry. The default login is
username: pi
password: raspberry

key based, password free SSH connection to your Raspberry

If the Raspberry will be only accessed remote without a GUI, normally SSH is the tool of choice. By default the user will use the login name and the password to connect to the Pi. While in Unix, Linux and OSX the user can connect with default tools under Windows putty will do the job.
Putty can be downloaded form http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html.

Generally there are some advantage of using key based SSH connections:

• the password will not be transferred over the network (not even encrypted)
• if your Raspberry is running online, you can reduce the probability of successful brute force attacks
• there can be automated connections to the raspberry

Generating the Key

To generate a SSH Key with Windows, in the first step download the PuttyGen tool from Putty project site. Check if the key type is SSH-2 RSA and the numbers of bits for the key are t least 2048. Click Generate to start the generation of the Key.

After the key has been generated, the window looks like this, showing the public part of the key and the fingerprint.

If you want to add a comment for the key, it might be easier to know what the key was generated for. Additional the key can be protected with a password. In the case of automated connections to the Raspberry, if you set a password, this will be asked for every connection. In my idea it is not necessary for my use case. Okay now everything is done and the private key can be saved. If the key will only used from Windows with putty, just click save private key. The filename extension should be ppk. If you want to use the key on Linux systems (to connect to the Raspberry), you need to export the key as OpenSSH Key.
In the example the public key will not be saved, because the key will be afterwards inserted into the Raspberry configuration. Therefore, the PuttyGen window will not be closed at the moment.

configure the Raspberry for SSH keys

Assuming the Raspberry is running and connected to the network, you will use Putty under Windows to create a connection with your user name and password. In most cases this should be the default user pi and the password raspberry

After the successful log in (with Putty!) you create a folder for the public SSH Key. The command is:

mkdir -p ~/.ssh

Next you create the file authorized_keys, in which we store the public key. The full path to the file will be /home/pi/.ssh/authorized_keys. This location creates a connection with the user pi and the public key.

sudo nano ~/.ssh/authorized_keys

In PuttyGen, select and copy the key from the window below the line "Public key for pasting into OpenSSH authorized_keys file" and insert with a right click into the Putty window with the open editor. The inserted key should be only one! line. If not, something is wrong. Jump with the end key to the end of line and check if the last characters form the authorized_keys file are the same as in the window form PuttyGen.

In nano text editor, the files will be saved with the key combination CTRL X, then Y then Enter. After the file is saved, we will secure it with the following command. Copy, paste and execute it line by line.:

sudo chmod 644 ~/.ssh/authorized_keys
sudo chown pi:pi ~/.ssh/authorized_keys
sudo chmod 700 ~/.ssh

Now the public key is stored on the Raspberry and is connected to a specific user. In the next step, a few settings for the key based SSH connection need to be checked or changed. The config file will be opened for editing with this command:  

sudo nano /etc/ssh/sshd_config

The following settings should be in the file (in different places or different order). If necessary, remove the number sign on the begin of the line (#).

PermitRootLogin no
AllowUsers pi
RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile .ssh/authorized_keys
PasswordAuthentication yes
UsePAM no

If anything has been changed in the file, this will be saved with CTRL+X, then Y and then Enter. In the last step the SSH daemon will be restarted with this command:

sudo systemctl restart sshd

configure Putty for key based SSH connections

Now there is some configuration on the SSH Client Putty. Open a new Putty window:

• Navigate in the Category tree to Connection -> Data and add under auto-login username your chosen user (here "pi")
  
• now navigate to Connection->SSH->Auth and enter path and file name to the private key
  
• as a last step navigate to Sessions and enter Host name or IP Address, chose a name for the session under Saved Sessions and click Save
  

For later connections open a Putty window, double click the saved session name and a connection to the Raspberry will be established. If the key based authentication was successful, the Putty window will look like this:

That's it, congratulations! You successfully created a private key, configured your Raspberry to use the public key for authentication and the Putty for establishing key based SSH connections. If this was helpful or you have an idea what I can improve, I would happy if you leave a comment.

Raspberry Shairport speaker in IKEA bamboo box

Round about two years ago, I started to play around with Shairport on Raspberry. Over the time the solution become a great part to listen podcasts and Music in the house. Unfortunately, a Raspberry and an attached speaker wasn't looking nice. Stumbling over the IKEA hack web page the idea was born to put the Raspberry in one of the IKEA bamboo boxes I had at home.
 
Assembling the hardware
Setting up the software

In the end the result will look like this.

The project did not focus to high end HIFI and therefore I did not spend any time calculating a perfect speaker. The equipment for the speaker is very cheap to keep the budget at a lower level.

Assembling the hardware

What did I use

• the bigger box of the IKEA Dragan bathroom dish set 
• a Raspberry Model A
• a SD Card (4 or 8 GB is more than enough)
• a KEMO M032N amplifier
• a Visaton FRS8 speaker
• a USB car charger
• some resistors, a potentiometer
• some wood
• and a piece of 
• acoustic fabric

 All together I spend less than 60 or 70 Euros - well for this price you will find wireless speakers with Bluetooth... probably also with better audio quality. But of course you will not find a Airplay compatible speaker nor have the fun of tinkering the things.

The amp uses 12V, so the box will run on 12V power source. The source of the Raspberry Pi is 5V. To convert the 12V input voltage I removed all plastic parts and from the USB charger and soldered some wires on it.

Before assembling the raspberry and the speaker into the IKEA box, I soldered the resistors and the potentiometer to a stereo to mono converter. The layout should be as in this diagram:

After finalizing the electrical work, I need to macgyver the box. Honestly I think that I am not very skilled for wood work but luckily all of this would be covered in the IKEA Box and by a piece of fabric :) I finished the assembling after I completed the software configuration because until the completion of the network configuration a keyboard and display was necessary.

Setting up the software

As in the most of my project i have chosen Raspbian as operation system. It's a Raspberry specific Port of the always stable Debian. What we need more?
Download the latest version of Raspbian Jessie from the Raspberry Pi project site. In a first step I removed all the unnecessary packages:

sudo apt-get purge console-setup desktop.* desktop-base dillo gnome.* gsfonts gtk.* gvfs.* libgtk.* libqt.* libxcb.* libxfont.* libxt.* lightdm lxde.* lxpanel omxplayer openbox penguinspuzzle python-tk python3-tk shared-mime-info tcl.* x11.* xarchiver xauth xdg-.* xkb-data xinit xserver.* wolfram

Afterwards the network configuration. First the WIFI passphrase will be stored as hash value in the conf file:

sudo wpa_passphrase mywifi mypass>> /etc/wpa_supplicant/wpa_supplicant.conf

In the next step the WIFI adapter wlan0 will be configured as DHCP, which means that the Raspberry will get it's IP address from the router the config file should look like this:

sudo nano /etc/network/interfaces

auto lo
iface lo inet loopback
allow-hotplug wlan0
auto wlan0
iface wlan0 inet dhcp
wpa-ssid "ssid"
wpa-psk "password"

The network configuration is complete and the interface can be restarted:

sudo ifdown wlan0 && sudo ifup wlan0

After a few seconds we check if the wifi interface has been connected to the Router and obtained a IP address:

sudo ifconfig

Next step was to update and upgrade the OS:

sudo apt-get -y update && sudo apt-get -y upgrade

After the successfull update a new firmware has been installed:

sudo rpi-update

Okay the OS is up to date, now we can install some necessary packages for Shairport:

apt-get install autoconf libtool libdaemon-dev libasound2-dev libpopt-dev avahi-daemon libavahi-client-dev git

The next step is to clone the Shairport sources from git

git clone https://github.com/mikebrady/shairport-sync.git

When it is done we change the directory

cd shairport-sync

an build the config files for the installation of Shairport

autoreconf –i –f

followed by a configure command with following options:

./configure --with-alsa --with-avahi --with-ssl=openssl

in the next step Shairport will be compiled from the cloned source

make

and finaly installed.

make install

For Raspian Jessie is a start up script nessesary, to ensure that Shairport will come up on boot. Create a new file with the following command

nano /etc/systemd/system/shairport-sync.service

and paste this contend (change the bold part for YOUR Shairport name):

[Unit]
Description=Shairport AirTunes receiver
After=sound.target
Requires=avahi-daemon.service
After=avahi-daemon.service
[Service]
Type=simple
ExecStart=/usr/local/bin/shairport-sync -a "MyShairport"
Restart=always
[Install]
WantedBy=multi-user.target

After saving the file, the script need to be added to systemd services:

systemctl enable shairport-sync.service

Done. Shairport can be started with the command:

systemctl start shairport-sync.service

to check if the start was successful:

systemctl status shairport-sync.service

The result should ne something like this.:

shairport-sync.service - Shairport AirTunes receiver
Loaded: loaded (/etc/systemd/system/shairport-sync.service; enabled)
Active: active (running) since Sun 2015-03-01 17:33:51 UTC; 3s ago
Main PID: 3040 (shairport-sync)
CGroup: /system.slice/shairport-sync.service
           ââ3040 /usr/local/bin/shairport-sync -a MyShairport

Mar 01 17:33:51 spi03 systemd[1]: Started Shairport AirTunes receiver.
Mar 01 17:33:51 spi03 shairport-sync[3040]: startup

Okay now we do a reboot and check if the Raspberry will obtain a IP address and Shairport is starting. If so, after a few seconds the Shairport will be available as target in iOS.

As I mentioned before, the final assembling has been done after successful software configuration. The result is a low budget Airplay player in a nice box. :)