Designing and building TMD-2 was a great  "stretch" experience for me. For the hardware, I had never worked extensively with the Raspberry Pi or Pi Camera. On the software side I had never used  Python or PyGame before. So I learned a lot  putting TMD-2 together.

Python is a great language but it took a little getting used to. I come from a mostly Java background so giving up on { } as block delimiters felt pretty unnatural. Even after a few months with Python, I still find myself wanting to put a ; at the end of lines. And I never did get the hang of using the _ in variable names, and stuck with camelCase. But that's just me. Python certainly lives up to it's cross-platform name. Development of the console application shifted smoothly between my Windows/Liclipse development environment and my Raspbian target environment. When I started integrating the camera and switched to the Pi for all my development, I found I was easily able to use RealVNC from my laptop to develop on the Pi, which gave me more screen real estate since the only display I had on the Pi was the a 7" touch-screen.

PyGame was recommended to me, and I'm glad that I chose it as the framework for the console. The only thing that I missed was some sort of GUI module. I tried integrating a number of the recommended external libraries, but in the end created my own dialogs in PyGame itself.  The disadvantage of doing this is that my implementations were a little feature light, but on the other hand maintained the aesthetic of the application.

There was more software development in this project than I thought there would be. When I first started, I was thinking of TMD-2 as the hardware successor to TMD-1.  I would build the hardware and write a little program for the console. Somewhere in the middle writing the console I realized that what I was doing would make a pretty good stand-alone application. I added features so that the program could be run without the camera based input, primarily allowing the state table to be edited with mouse clicks. And since Python is cross platform, it would run almost anywhere. In the end I was thinking of TMD-2 to as a Turing machine program, that took the ease of use and simple to program concepts from TMD-1, and made them accessible to a much wider audience.  TMD-2 also supports a cool optional tile based interface for defining the state transition table.

I think with the completion of TMD-2 that I have Turing machines out of my system for a while.  On to the next project whatever that might be.