Fluidic Logic

The inspiration for this prototype was initially sparked by (1) seeing the words "Physical Computing" in the tinkering lab at the Exploratorium and (2) wanting to use the motion of water in my prototype, either for hydraulic power or simply as its own phenomenon. So, the idea of a water computer was the obvious next step!

After researching fluidic logic for a while, I came across a similar project by Paulo Blikstein, who is a professor in the Graduate School of Education. His project was to make a half-adder, which takes two inputs and outputs their sum as its result.

I liked the fluidic logic design he created, but in terms of making an interactive exhibit that demystifies computing, there were a couple of changes I needed to make:

• Making the results easier to interpret. This is a crucial idea in the notion of physical computing: that physical phenomena can be interpreted as computational phenomena. Since water is always flowing through the system, it's important to signify what outputs are meant to symbolize. In my first prototype, I marked the outputs for each logic gate as either "OUTPUT" or "WASTE" to try to address this issue. In my next prototypes, I aim to try additional ways of signifying the result: potentially a moisture sensor under the OUTPUT tube, and/or an opaque waste tube, could contribute to that goal.
• Using simpler logic pieces as atomic elements of the exhibit. While it's cool to have a single object that acts as an adder, this makes it more difficult to see what's going on, and limits opportunities for users to put logic circuits together themselves. My prototype uses larger reservoirs representing basic Boolean logic gates to accomplish this task. In later iterations, I'd like to make it easier for users to assemble circuits by streamlining the process of attaching the pieces to a wall and to each other.
• Making the physical phenomenon more visible. The half-adders were fairly small, which makes their inner workings harder to directly observe. Being able to see flow on a larger scale might make the exploration more accessible. Later, I'd like to increase the rate of flow by using larger tubes, but this will require planning to determine how much water will need to be continuously flowing through the system.

My prototype is designed with the goal of demystifying computing in mind. Because computer science is a highly formalized, abstract and mathematical enterprise, it can be intimidating to people. Moreover, because of the scale and complexity of computers we use in our daily lives, computation can seem to take on a 'magical' quality (Genevieve Bell has an interesting talk on this topic). I think that physical computing is a really interesting way of addressing these issues, because it's uniquely able to show people the inner workings of computation, particularly in a way that can be experienced and investigated directly.