There is a lot of hype about the Arduino in the theatrical world right now. The open source microprocessor provides a platform to base new design ideas and different solutions for old problems like triggering sound effects on an action. The Arduino allows for electronics that can be completely customizable to a large extent, and is very affordable, however at the lower price it starts to suffer from functional shortcomings.
First and foremost being memory. The chip can only hold so much information on it, and this isn’t just how large the program uploaded is, but also the buffers and allocated memory that the program needs to run. To make an LED blink is a simple program, however when we get into more complicated actions, such as communicating through midi or DMX the program becomes much more complex and needs to hold large amounts of information.
Secondly, the timers and the logic has some latency problems. The timers can only be so accurate and when pushing the processor the it tends to slow down in its computation, like an computer.
New solutions are emerging however, the Raspberry pi (http://www.raspberrypi.org/) is the next step. This board is more like a computer. It has a graphic user interface and allows for USB connections and ethernet connections built in. The board boasts a better processor, better networking capabilities, and easier integration with store bought technology.
These both have their Pros and Cons, but in a world that is becoming more integrated with technology and where more people are willing to learn rather than buy, i foresee these boards become very powerful, very quickly, and having many more uses in theater than we know now.