I spy with Raspberry Pi

Prepare to dive deep

Raspberry Pi for Secret Agents. Trendy title. While I wondered how serious it could be, the author's name got my attention - Stefan Sjogelid. Now that is already promising. This is the guy behind the idea, that if you're eager enough, you can build your own Linux distribution targeted at the Raspberry Pi architecture. The whole process is thoroughly described on his dedicated web site. And expectations slowly started to rise.

Now with this book we're in for a treat. At least we don't get the usual starter point of view, and get some trickery instead. The book is very educating on an operating system level. Reading it, I was able to fill some large gaps in my modest but constantly expanding Linux knowledge. Once the reader starts, it quickly becomes clear that the installments built up are simple enough, yet powerful and effective. And I wouldn't be surprised if such tools are employed in a real-life espionage activities.

The layout of the book is presented to be dead simple. Its significance is another story :)
After the mandatory introduction of the Raspberry Pi's basics (in terms of hardware and OS) to the reader in the first chapter, the actual contents related to the main topic begin  from the second one. The four sub-topics of the book are respectively: Audio, Video, WiFi and Portable Pi. The simplicity is only on the surface. 

Concerning the audio tasks, at first I had a difficulty to set-up a microphone due to my profanity. Without giving the proper attention to all of the Pi's interfaces I was (wrongfully) thinking that the audio output connector can deliver also an input. After a few lessons learned and a correct setup I was ready to meet some handy tools. Most of the chapter is dedicated to the SoX tool - the working horse of the audio mechanics. Combined with the rest of the tools (some of which are built-in Linux commands) and through the secure shell a lot of possible "spy techniques" are given. Those tools include tmux, espeak and at commands. They're for running SoX independently of the user's session, for speech and task-in-time automation respectively. 
Apart from the auxiliary elements the main idea is to be shown how the ALSA sound system is employed in the Raspberry Pi, and how easily it can be used for various projects.

Regarding the video tasks, maybe the book was written and released a bit too early, because two weeks ago the guys behind the Raspberry Pi released its own camera, plugged into the dedicated CSI connector. I guess that if written today, this chapter would look a bit different. At least it could include additional information about the Pi camera and its dedicated software tools and capabilities.
Well without that info the chapter is comprised of two main projects - video streaming with recording the stream and detection of moving objects. 
For the purpose of the first task the tools related to the framework around the UVC and V4L drivers are used in order to generate a MJPG video stream. The stream then can be accessed on the network by the VLC media player and if necessary recorded by it (without sound of course).
And for the purpose of the second task the very powerful Motion software is shown to easily gather input from even more than one camera.

The chapter about the WiFi networking can make a very nice addition to another of the PACKT's books, which I reviewed recently. Here the tool of the trade is the detection system Kismet. For it to work not only configuration but also building from source is required. And to be preserved consistency between the projects (and between the chapters of the book of course) it is shown a collaboration with SoX for the purpose of attaching sound signals to its processing events.
Further a network mapping is done with Nmap, which leads to the logical next step - to dive into the common (or not so common) network security techniques for attack and/or monitoring with programs like Ettercap and Wireshark.

In the last chapter the Raspberry Pi had to prepare its back-pack, for it was going on a field trip. Regarding the mandatory warnings for battery life, secure and low profile package and most importantly - avoiding any moisture, the portable computer can pretty quickly step outside.
Setting up an ad hoc WiFi network is not difficult following the instructions in this (and partly in the previous) chapter. 
Two of the most interesting projects in the book (which I unfortunately haven't tested yet for some reasons) are the GPS tracking of the Pi in Google Earth, and remote controlling it from a smart-phone while tweeting its current status to the social media. Merely reading through them, they seemed to comprise a powerful, portable setup and just whet one's appetite for some future projects.

The book aims to teach us how to employ the Raspberry Pi in a set up that is robust, automated and portable. All of these are actually achieved thanks to the software tools built-in or separately added to the Linux operating system. In that sense this could be regarded as the only (although not real) drawback of the book. The small computer is there, but still in the background. Everything described can be done on a regular Linux system's shell. No wires, no soldering, no bread-boards, no hardware projects. Yet the Pi is most suitable and prepared for taking these actions to the field and in real life situations. So the existing hardware is enough to become the real spy and the book just gives the vision on how prepared it is to do the job.

In conclusion I can say that this book very easily achieves the goal of being funny, informative and deep at the same time.