We kicked off our final chapter with a few words of advice about taking your Pi outside the house. You learned that a battery pack is a good source of power for the Pi and that you can be very creative with your housing as long as the container is resistant to moisture.
As you wouldn't bring a router or access point with you outside, we looked at how to connect a laptop directly to the Pi using either a wired connection with static IP addressing or an ad-hoc Wi-Fi network. Should you need to connect more than two computers, you also have the option of turning the Pi into a Wi-Fi access point with optional Internet sharing, including connecting to the mobile Internet using a USB modem dongle. Concluding our look at Internet connectivity, we became anonymous on the Internet by connecting to the Tor network.
We then expanded our outdoor adventure with a GPS receiver and saw how to track the Pi's position in real time on Google Earth. You also learned how to log waypoints along the route, so that the journey can be retraced on Google Earth at a later time, and how to massage GPS data collected from Kismet into an access point map. Finally, we explored the GPS as an alternative time source for the Pi and how all the GPS features we've covered could be started at boot time with a simple script.
We moved over to our smartphone for a spell and saw how an Android or iPhone app could be used to construct a custom remote control by sending commands over SSH to the Pi at the touch of a button.
Proving that machines can also be social, we let the Pi post status updates on Twitter on a regular basis with an optional link to a longer document and GPS coordinates. We could also let it send e-mails to inform us about important updates at regular intervals using the Cron scheduler.
Sharing files between the Pi, and all your other devices, was made a little easier using the Dropbox online file hosting service, where a common folder can be kept synchronized and up to date among all computers.
We took a closer look at data encryption and how we could create a vault to hold selected sensitive data. We then expanded upon the idea to encrypt our home directory and saw how to implement an optional self-destruct mechanism that would wipe the home directory clean in case of tampering.
Finally, we looked at how to create the ultimate mayhem by using our Pi as an FM transmitter and jammer, and taking over the airwaves using a clever piece of software and a short piece of wire.
In our next and final chapter we're going to protect our territory from enemy spies and unwanted intrusions using a variety of sensors and gadgets.