Beaglebone: Using an USB WiFi dongle to connect to wireless networks at boot.

I'll cover how I configured my BeagleBone so it now (automagically) connects to wireless networks at boot.

Note: I assume you are running Ubuntu 12.10 in your Beaglebone.

Manual connection

First, let's check whether the Beaglebone can use the WiFi dongle by setting up a manual connection.

Before starting the test, let's install some software with the ethernet cable plugged in:

#On the beaglebone
sudo apt-get install lshw
sudo apt-get install wpasupplicant

Now unplug the Ethernet cable from the Beaglebone. And start a connection using the USB emulated Serial connection.

# On the PC
screen /dev/<ttyUSBx> 115200

Now let's check if the Beaglebone has recognized the WiFi dongle.

# On the beaglebone
lshw -C network

I got this:

*-network:1 DISABLED
description: Wireless interface
physical id: 2
bus info: usb@1:1
logical name: wlan0
serial: d8:eb:97:12:e4:c0
capabilities: ethernet physical wireless
configuration: broadcast=yes driver=rtl8192cu driverversion=3.2.33-psp26 firmware=N/A multicast=yes wireless=IEEE 802.11bgn

If you see something similar, it means your device has been detected by the Linux kernel and an appropriate driver has been loaded.

Remember the logical name, in this case is wlan0.

Now, turn on the WiFi dongle. (Use the logical name obtained from the last command)

# On the beaglebone
sudo ifconfig wlan0 up

Blue LED indicates that the WiFi dongle has been turned ON.

Scan for visible WiFi networks.

# On the beaglebone
sudo iwlist wlan0 scanning

You should see your network in the list:

wlan0     Scan completed :
          Cell 01 - Address: 00:13:49:CA:F5:10
                    Channel:4
                    Frequency:2.427 GHz (Channel 4)
                    Quality=56/70  Signal level=-54 dBm
                    Encryption key:on
                    ESSID:"your-ssid"
                    ...

Now, let's connect to your network.

# On the beaglebone
sudo nano /etc/network/interfaces

Append or modify the file to include the following text (I'm assuming your network it's WEP protected):

auto wlan0
iface wlan0 inet dhcp
    wireless-essid <ssid>
    wireless-key s:<ascii key>

Next, start the connection

# On the beaglebone
sudo ifup wlan0

And finally, test the connection

# On the beaglebone
ping www.google.com

Congratulations, you have connected to a wireless network.

Going automatic

We'll use wpa_supplicant to automate the connections to wireless networks.

wpa_supplicant is a daemon that manages unsecure, WEP and WPA wireless connections.

wpa_supplicant stores the information about the wireless networks that it can connect to in a .conf file, usually named wpa_supplicant.conf.

You can create/edit it, using:

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

This is how it should look like:

ctrl_interface=/var/run/wpa_supplicant

# Unsecure Network
network={
    ssid="<ssid>"
    key_mgmt=NONE
    priority=<unsecure_priority>
}

# WEP Network
network={
    ssid="<ssid>"
    key_mgmt=NONE
    wep_key0="<key>"
    priority=<wep_priority>
}

# WPA Network
network={
    ssid="<ssid>"
    psk="<passphrase>"
    priority=<wpa_priority>
}

For more examples about the .conf file, check this website.

Let's reconfigure the network interface to add support for wpa_supplicant.

sudo nano /etc/network/interfaces

Change the wlan0 part to match the following text:

auto wlan0
iface wlan0 inet dhcp
    wpa-driver wext
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

Finally reboot the BeagleBone to see the changes.

sudo reboot

Done!

Beaglebone: Installing Ubuntu 12.10

I've got my hands on a Beaglebone, and the first thing I did was installing the latest Ubuntu 12.10 on it. Here how I proceeded.

This post is mainly for self-documenting, feel free to follow my footsteps at your own risk. These steps will probably also work on the Beagleboard.

Back up the original image

The Beaglebone comes with the Linux Ångström distribution. So I backed up the original image, in case something failed. Even if I were to stick with the Ångström distro, it's a good idea to back up the original image.

I removed the microSD that shipped with the Beaglebone, and inserted it into my PC SD slot. Then I checked in which partition it got mounted, using the following command.

df -l

/dev/sda is my PC harddrive, and /dev/sdb is the Beaglebone SD card.

After identifying where the SD was mounted, I used the following command to backup the SD.

dd if=/dev/<sdx> | gzip > /path/to/image.gz

In case I needed to restore the image, I'll have to use the following command:

gzip -dc /path/to/image.gz | dd of=/dev/<sdx>

Installing Ubuntu

I followed the instructions from elinux. These are the summarized steps:

• Download the minimal Ubuntu 12.10 image

cd ~/Desktop
wget http://rcn-ee.net/deb/rootfs/quantal/ubuntu-12.10-r2-minimal-armhf-2012-11-29.tar.xz

• Verify the integrity of the image

md5sum ubuntu-12.10-r2-minimal-armhf-2012-11-29.tar.xz

Which should match the following output

b0ee1964a3f8196f4f1a501d1d2ac83a ubuntu-12.10-r2-minimal-armhf-2012-11-29.tar.xz

• Untar the package

tar xJf ubuntu-12.10-r2-minimal-armhf-2012-11-29.tar.xz
cd ubuntu-12.10-r2-minimal-armhf-2012-11-29

• Flash the image into your SD

sudo ./setup_sdcard.sh --mmc /dev/<sdx> --uboot bone

Finished flashing the Ubuntu image into the SD card.

For the record (Older releases):

Release 1: http://rcn-ee.net/deb/rootfs/quantal/ubuntu-12.10-r1-minimal-armhf-2012-10-19.tar.xz
MD5: 31be6761a37af98906c5c1e892601e85

Connecting to your Beaglebone

After flashing the Ubuntu image, I removed the SD from my PC and plugged it back into the Beaglebone. I decided to make the first connection using the tty over USB.

After connecting the Beaglebone to my PC using a USB cable, I had to figure out the exact name of the ttyUSBx with the following command.

dmesg | grep ttyUSB

From documentation, ttyUSB0 -> JTAG, ttyUSB1 -> UART (terminal)

I used GNU screen to stablish the connection:

sudo apt-get install screen
screen /dev/<ttyUSBx> 115200

After the connection was established. I saw no output so I pressed the reset button on the Beaglebone.

Voilà

The default login information is below.

• login: ubuntu
• password: temppwd

Things to do after installing Ubuntu

OK, I logged in! ... Now what?

Change your password

First thing first, I changed the default password to something stronger

# On the Beaglebone
passwd

Connect the Beaglebone to the internet

I plugged an Ethernet cable into the Beaglebone, and checked if the connection was OK.

# On the Beaglebone
ping www.google.com

I let ping run for a while and then I finished it with Ctrl+C.

Notice the "0% packet lost", that's a Win.

OK I lied, it didn't work the first time, I got 100% packet lost, but resetting the Beaglebone solved the problem.

Autocompletion

Next, I enabled bash completion - a.k.a. the tab autocompletion:

# On the Beaglebone
sudo apt-get update && sudo apt-get install bash-completion

Change the hostname

The terminal prompt says "ubuntu@arm". This means the Beaglebone hostname is "arm". I changed that with the following commands.

# On the Beaglebone
cat /etc/hosts

I got the following output.

# On the Beaglebone
127.0.0.1 localhost
127.0.1.1 arm

So I changed the second line with:

# On the Beaglebone
sudo nano /etc/hosts
# changed the second line from arm to <new-hostname>

Next, I did:

# On the Beaglebone
cat /etc/hostname

And got:

# On the Beaglebone
arm

I changed that with:

# On the Beaglebone
sudo nano /etc/hostname
# changed the hostname from arm to <new-hostname>

Finally I rebooted the Beaglebone to apply the changes.

# On the Beaglebone
sudo reboot

Change your login name

Now the terminal prompt says "ubuntu@beaglebone", the login is "ubuntu". I also changed that.

I had to enable the root account:

# On the Beaglebone
sudo passwd root
# Entered a temporary password

Pressed "Ctrl + D" to logout and I logged as root:

Logging as root.

I changed the old username with:

# On the Beaglebone
usermod -l <new-username> ubuntu

I also added a comment to my new user:

# On the Beaglebone
usermod -c "<full-name-or-comment>" <new-username>

Next, I moved to my new home:

# On the Beaglebone
usermod -md /home/<new-username> <new-username>

Finally, I also renamed the "ubuntu" group to match my new username:

# On the Beaglebone
groupmod -n <new-username> ubuntu

I logged out (Ctrl + D) and logged with my new username:

Logged with my new username.

Finally I locked the root account:

# On the Beaglebone
sudo passwd -l root

Set up a zeroconf hostname

A zeroconf hostname, simplifies SSHing with a local machine by assigning it a hostname on the LAN. This way I don't need to know the IP (which can change over time) to start a SSH session.

#On the Beaglebone
sudo apt-get install avahi-daemon

Now I can connect to the BeagleBone via ssh using the following command:

# On the PC
ssh <beagle-username>@<beagle-hostname>.local

SSHing the Beaglebone

I finished the screen session, using Ctrl+A and then K. I rebooted the Beaglebone, this way the avahi daemon got launched on the next boot.

ssh jorge@beaglebone.local instead of ssh jorge@192.168.1.x

SSH login without password

Everytime I SSH'ed the Beaglebone I needed to input the Beaglebone login and password. The next commands got rid of that.

# On the PC
ssh-keygen # Don't enter a passphrase
ssh-copy-id <beagle-username>@<beagle-hostname>.local

SSH without login

Install GNU screen

I quickly found out that I needed multiple SSH sessions to open multiple terminals on the Beaglebone. Searching for a workaround I found GNU Screen.

With GNU screen I can create multiple "screens", with one terminal inside each of them. All this can be done with keyboard commands.

#On the Beaglebone
sudo apt-get install screen

To start screen I needed to use the following command on every login.

#On the Beaglebone
screen -S 1

This was annoying, so I automated the task:

# On the PC
gedit ~/.bashrc

I appended the following text:

Now with a single command, I can SSH login into the Beaglebone and enter in a running "screen" or create a new "screen", if it doesn't exists.

#On the PC
sshbeaglebone

SSH session with the Beaglebone splitted in 3 using screen.

Other important software

I also installed additional software:

#On the Beaglebone
sudo apt-get install man-db # Manuals
sudo apt-get install vim # Text editor
sudo apt-get install octave # Numerical package
sudo apt-get install build-essential # make, gcc, et al.

What's next?

• Convert Vim into an IDE.
• Using an USB WiFi dongle to connect to wireless networks at boot.
• Figure out how to access (with C or ...Python?) the Beaglebone hardware registers. Sorry, no time for this one, you might want to check PyBBIO. Good Luck!

Acknowledgements

• The BeagleBoard community for producing the Beaglebone.
• The Embedded Linux community for their tutorial on how to install Ubuntu on the Beagles.
• Brandon Mintern for his great post about SSH and Screen.