Posts for Tag: angstrom

BeagleBone Black - iPhone as keyboard/mouse

Note: I wrote this a while ago specifically for my BeagleBone Black so some of the instructions refer to "opkg" - the package manager used by Ångström Linux. It looks like they've moved on to use Debian instead of Angstrom nowadays, but realistically you can adapt this guide and use the software on any linux distro on any device.

I thought it would be an interesting exercise to use my iPhone as an input device instead of a physical mouse and keyboard. It turns out it's pretty simple, thanks to Tuomas Räsänen's cool python-uinput module together with pybonjour for simple device discovery via Bonjour.

The "server" running on the Beagle and the iOS "client" (bad metaphors, sorry) can be retrieved via git:

$ git clone https://github.com/smcl/iBeagle
$ cd iBeagle

Preparing your Beaglebone Black

First copy the file iBeagle.py file to your beagle.

$ cd iBeagleServer
$ scp iBeagle.py beaglebone.local: # or whatever the username/IP is

Next there's a little bit of setup on the BeagleBone Black is required, as a kernel module and a couple of libraries are required

$ ssh beaglebone.local

Load the "uinput" module. this requires libudev

$ sudo modprobe uinput

The python module for uinput we're using requires udev-systemd, so install via opkg

$ sudo opkg install udev-systemd
$ git clone https://github.com/tuomasjjrasanen/python-uinput.git
$ cd python-uinput && sudo python setup.py install

Ensure avahi-daemon process is up and running

$ ps ax | grep avahi | grep running

Finally setup pybonjour - bonjour library I used for this. If you're having trouble relating to libdns_sd.so see the section "Appendix - udev trouble" at the end.

$ pushd /usr/src
$ wget https://pybonjour.googlecode.com/files/pybonjour-1.1.1.tar.gz
$ pushd pybonjour-1.1.1
$ tar -xzf  pybonjour-1.1.1.tar.gz
$ cd pybonjour-1.1.1
$ python setup.py install

Finally return to your iBeagleServer directory and run the client

$ popd && popd
$ python iBeagle.py

Preparing the iPhone Client

Currently you need to load the application using Xcode, so you'll need an iOS dev account and an iOS device authorised to your account. Open up iBeagleClient/iBeagleClient.xcodeproj, and build + run on your hardware.

When the server is running you should see your BeagleBone Black listed on the table when you launch the app. If not then try restarting the server, or waiting a few seconds.

Appendix - libudev trouble

I actually had a bit of trouble with this step initially. libdns_sd.so was missing, so I retrieved the avahi sources and built my own copy. The libdns_sd.so library was missing on my version of Angstrom Linux, so I built and installed it separately (which is slightly hacky, there's probably a more sensible way to achieve this)

$ wget http://avahi.org/download/avahi-0.6.31.tar.gz
$ tar -xzf avahi-0.6.31.tar.gz && cd avahi-0.6.31

We need to grab some pre-requisites + set PTHREAD_CFLAGS

$ export PTHREAD_CFLAGS='-lpthread'
$ sudo opkg install libssp-dev
$ sudo opkg install libintltool

And run configure so we only build as little as possible to just get the library we want

$ ./configure --disable-static --disable-mono --disable-monodoc --disable-gtk3 --disable-gtk --disable-qt3 --disable-python --disable-qt4 --disable-core-docs --enable-compat-libdns_sd --disable-tests --with-distro=none
$ make

Then (without running make install) we copy libdns_sd.so and libdns_sd.h into /usr/lib and /usr/include respectively

$ cp ./avahi-compat-libdns_sd/.libs/libdns_sd.so /usr/lib
$ cp ./avahi-compat-libdns_sd/dns_sd.h /usr/include

In my case it was trying to use libdns_sd.so.1 - so I also created a symlink to libdns_sd.so.1.