Friday, October 19, 2007

05: switch



Eureka! I love it when in a moment you feel as though you have a better grip on the trajectory of your work. While performing the vivisection on the pony I came across a really interesting circuit board//switch called a slip ring. "A slip ring (in electrical engineering terms) is a method of making an electrical connection through a rotating assembly" (source: wikipedia.org)*. After a brisk survey of slip rings on-line I realized that most of them are commercial grade and so the connections are hidden within the casing. Not great for the inquiring rookie. Basically, the slip ring works in a rather rudimentary and beautiful way. The disc is a multi-layered circuit board. The top is connected to the underside via tiny conductive holes (Image 1 far left) . Each colored wire is a different switch. The top side shows a continuous circuit which permits the colored wire to only be connected in one place (Image 2 middle) - otherwise the wire would have to connect to each of the semi-circular patches on the bottom side. The bottom side shows the on/off function of the switch. As the key (Figure 3 far left) touches the pattern it creates a connection between the central most circle (called the common) and one or more of the patches. When this happens the switch connected to that path is turned on. When the key rotates off the patch the switch turns off. What is demonstrated is a direct relationship between time and distance - the larger the patch the greater the distance the key will have to pass and the longer the switch will be turned on.

Next steps: The switch function is definitely worth pursuing further. I intend to make my own switch using D.I.Y circuit board techniques such as the ones seen here. The question then really becomes what do I want this switch to control? Unfortunately, I'm still trying to figure out what the slip disc was responsible for activating within the pony. My best guess is syncing the variety of leg movements with the voice recordings. In that case, it would be fairly straight forward to have the switch operating on motors. So what to the motors do? The second issue is that once I commit to the switch I maybe precluding the use of programing and a microcontroller set up in the project. Something I'm also interested in. The switch itself is a rudimentary form of programming with a digital on/off function. Perhaps I could introduce some analog life into the overall design through a micro-controller. My hunch at this point in time is that the switch will control the puppets operation when human interaction is not sensed. However, once the machine senses someone to interact with the system will evolve.

* Don't give me grief about this source!


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