Meet the VoCore, a coin-sized Linux computer

SSH and Software

The second way to access the VoCore is via a Secure Shell (SSH) connection. On Linux and Mac OS X, you can do this by opening a terminal window and typing:

$ ssh root@<your Vocore's IP>

In my case, that's:

$ ssh root@192.168.1.108

From Windows, you'll have to use something like PuTTY [3].

Again, use vocore as your password (you might want to change that at some point), and you'll drop into a Bash terminal. From here, in classic Linux fashion, you can manage most things on your device and then some. To check to see whether the VoCore is connected to the Internet, type:

# ping raspberry-pi-geek.com

You should see your VoCore connecting and sending and receiving packages from the Raspberry Pi Geek servers.

You can also install new packages (note that this can also be done from the web interface: Visit System | Software to see what is installed, what is available, and then pick and choose packages to install (Figure 8).

Figure 8: You can install new software by visiting System | Software on the web interface. You will also be able to see how much free space is available.

The package manager used in OpenWrt is called OPKG and is very similar to the Apt utility used in Raspbian. If you run

# opkg list

you will notice the list of available packages is very small. Here, you might hit your first snag with the unit: It turns out that when you try and update the repository list with

# opkg update

you could get an HTTP/1.1 404 Not Found error. This is because the addresses of the repositories have changed since the version of OpenWrt that the VoCore currently runs. Fortunately, solving this problem isn't that difficult. All you have to do is update the list by hand.

The default OPKG repository list is stored in the /etc/opkg.conf file and looks similar to Listing 1, except the default repositories do not have /generic/ in the path. A little research shows that, indeed, neither of the addresses in the VoCore OpenWrt version of opkg.conf exist anymore. Therefore, you only have to substitute the defaults with the two new addresses, as shown in lines 5 and 6.

Listing 1

Corrected opkg.conf

01 dest root /
02 dest ram /tmp
03 lists_dir ext /var/opkg-lists
04 option overlay_root /overlay
05 src/gz cheese_base http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/base
06 src/gz cheese_luci http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/luci

You can do this by opening /etc/opkg.conf with the Vi command-line text editor. Or, if you are uncomfortable with Vi, you can use the web interface and visit System | Software and click on the Configuration tab.

Now if you run the commands

opkg update
opkg list

the update completes without a hitch and the list of packages is much more populated.

However, you'll still find some glaring absences. For starters, you won't see any high-level languages like Python or Perl. To install those, you'll need to include a new repository in /etc/opkg.conf. Add:

src/gz cheese_packages \
  http://downloads.openwrt.org/snapshots/\
  trunk/ramips/generic/packages/packages

at the end of your file and run opkg update again. The next time you run opkg list, the roster will be considerably longer and will include Python, Perl, and other packages. You can also include other repositories, such as those shown in Table 1.

Table 1

OpenWrt Standard Repositories

Name

Description

Address

Base

Essential packages needed by OpenWrt.

http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/base

LuCI

Packages needed by the web interface LuCI.

http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/luci

Management

System administration tools.

http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/management

Packages

Generic packages that don't fit into any other category. This is where you will get most of your software.

http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/packages

Routing

Packages that convert OpenWrt into a fully fledged routing system.

http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/routing

Telephony

Packages that allow you to convert OpenWrt into an IP telephony system.

http://downloads.openwrt.org/snapshots/trunk/ramips/generic/packages/telephony

Note, however, you cannot go mad installing stuff on the VoCore, because you have at most 16MB to play with. Be selective.

To see the description of a specific package, type

# opkg list <name of package>

The difference between OPKG and a more advanced system (e.g., Raspbian's Apt) is that, if you type

$ apt-cache search python

in Raspbian, you will get all the packages that contain the word python in their name or description. This is useful if you are not only looking for Python itself but also for modules or tools for the language. However, with OPKG, typing

# opkg list python

only shows you the description of the package with that exact same name, (i.e., the base Python package). To get a whole list of packages that contain the word python, you can sieve OPKG's results through grep:

# opkg list | grep python

To install a package use:

# opkg install <package name>

To remove it, use:

# opkg remove <package name>

You can find a full list of OPKG commands online [4].

Updating

You can also update VoCore's whole system. Many larger devices, like your phone or desktop computer, have both firmware and an operating system. However, for most embedded devices it's all one and the same, so OpenWrt is the VoCore's firmware as well.

You can get the latest OpenWrt distribution compiled for VoCore online [5]. Open the web interface and go to System | Backup/Flash Firmware. If you have been working with the device for a while, it might be a good idea to Download a backup. Click Generate archive, and you will be able to download a tar.gz file to you computer (Figure 9).

Figure 9: Getting ready to flash a new firmware onto the VoCore.

Move down to Flash new firmware image. If you have already configured your VoCore to join your network and whatnot, you might want to make sure the Keep settings checkbox is marked. Click Browse and navigate to the .bin file you downloaded previously [5]. Make sure your VoCore is safely plugged in to the mains and won't get unplugged during the flashing process, because, if it does, you'll brick it.

Click Flash Image. Flashing could take a few minutes, and the VoCore might be assigned another IP when it comes back online. Be patient; wait for 10 minutes and then check to see if it is back.

If you visit VoCore's upload page [6], you can find more custom spins of VoCore-customized firmware. Look for files ending in .bin. Some, for example, implement partial support for the microSD card reader on the dock (yes, that is still a work in progress); others do away with the LuCI web front end to make more space for other stuff.

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