Arduinos, Androids, and iPhones, Oh My!

With the meteoric rise of mobile device proliferation, the post-PC moniker has made its way into the tech world’s vocabulary. I am a big proponent of technology shifts, but I am also old enough to have lived through three major computing revolutions (the shift from mainframes to PCs, the rise of the Internet, and the shift from PCs to mobile devices) and know that change isn’t as fast as people say it is. Until mobile applications can be developed on mobile devices the way PC applications can be developed on PCs, a Linux, Windows, or Mac computer will be a central requirement for developing mobile apps. The same holds true for Arduino programming.

That said, the times are indeed a-changing. Microsoft Research was one of the first major phone OS providers to attempt to create native mobile applications directly on the mobile device with their release of TouchStudio. Google engineer Damon Kohler created the Scripting Layer for Android (SL4A) that gives Android users the ability to write fairly sophisticated programs using a text editor on their phone. Coupled with Sparkfun’s IOIO (“yo-yo”) board, we’re already seeing early glimpses of what could replace the PC for some of the scripts created for this book.

Since you will need a Mac, Linux, or Windows computer to program the Arduinos and mobile apps in this book, this computer will also be the machine that runs the server-side programs that interpret and extend information out to your mobile devices. Of course, if you only have one computer and it’s a laptop that travels with you, consider purchasing a cheap Linux or Mac to run as your home server. Not only will you benefit from having a dedicated system to run the monitoring apps 24/7/365, but it can also serve as your home Network Attached Storage (NAS) server as well.

I am a believer in open source hardware and software. As such, the projects in the book depend upon these. I am also technology-agnostic and rarely have any overriding devotion to one hardware supplier or programming language. Code for this book could have been presented just as easily in Mono-based C# and Perl, but I opted for Ruby and Python because of their portability and multiparty open source support. I could have used a Windows or Linux machine as the server and development system but chose Mac for the book because Ruby and Python are preinstalled with the OS, thereby eliminating the time and space required to install, configure, and troubleshoot the operating environment.

In accordance with this open source philosophy, I also opted to demonstrate the mobile application examples exclusively for the Android OS. While I personally prefer iOS devices as the platform of choice for my mobile lifestyle, the overhead associated with writing applications for iOS is a hassle. In addition to learning Objective-C and the various frameworks as well as dealing with the burden of memory management, deploying iOS apps requires either a jailbroken device or the legitimate purchase of an annual membership to Apple’s iPhone developer network. Conversely, Android’s SDK and application deployment is free and open. Android programs can also multitask better than iOS programs. Of course, these two advantages also bring on greater security and resource utilization risks. That said, I encourage readers who prefer the mobile demos to run on non-Android devices to port the simple client programs presented in this book to their favorite mobile OS and share these conversions with the Programming Your Home community.

Another term that is gaining a foothold in the tech press is the “Internet of Things.” This phrase refers to the idea that with the proliferation of network-connected microcontrollers, Internet-based communication between such small devices will eventually outnumber people surfing the Web. While that may be the case for submitting data upstream, reaching such a device from the Internet is still a hassle. Besides the technical knowledge required to set up a dynamic DNS and securely configure port forwarding to easily reach the device, ISPs may block outbound ports to prevent end consumers from setting up dedicated servers on popular network ports like FTP, HTTP/S, and SMTP.

The projects in this book should work perfectly fine in a home local area network. However, obtaining sensor data outside of this local network is a challenge. How do you check on the status of something like a real-time temperature reading without going through the hassles of opening and forwarding ports on your router (not to mention the potential security risks that entails)?

Fortunately, several companies have begun to aggressively offer platforms accessible via simple web service APIs to help overcome these hassles. Three of these gaining momentum are Pachube, Exosite, and Yaler.[1] Configuring and consuming their services is a fairly straightforward process. I encourage you to visit these sites to learn more about how to incorporate their messaging capabilities into your own projects.