I’ve been thinking a lot about the scroll roller over the past couple of days. Tims took it back to his place on the subway, and he tossed me an email saying that there were a lot of people who were very interested in it just from the way it looked, I thought that was really neat. With the show just occurring, I have also been giving a lot of thought to what it would take to make the scroll roller really ready for public demonstration. I’ll talk more about that later, but I figured it might help to talk about its current state first.
I’m going to include a bunch of pictures with explanations. These were all taken on the ITP light table. I have to say that a light table makes everything look better. I feel as if the scroll roller is far less impressive looking than these photos make it, but maybe that’s just over-exposure to the thing. Anyway, without further ado:
The scroll roller in its current incarnation is a very simple device: a potentiometer for control, run through a microcrontroller, which runs through an H-bridge to control a pair of DC motors which are connected to the axles the scroll is set on. Tiltng the lever hooked up to the potentiometer in one direction the scroll moves one way, and if you tilt the lever the other way the scroll moves the other way. The farther you tilt the lever the faster the scroll moves, so you can have both fine control and move quickly using a single input device.
Scrolls are (currently) mounted on specially prepared lengths of PVC pipe which have lugs attached to them that match up with the lugs on the axles connected to the motors. The axles are held in place by sliding latches, so all you have to do to get one is side the latch open and pop out the axle. Then you slide your scroll into place and lock the axle back down.
You get a device that looks, I happen to think, pretty good. Even in its current rough-prototype stage. Part of this is the way the light table makes things pretty, but it’s just a generally aesthetically pleasing object. I especially like the way that the roller seems to be a frame of sorts, accentuating rather than distracting from the scroll.
While this prototype has a number of problems on the technical end, I think they’re mostly materials-based. In fact, the core design seems very sound, hurt primarily by the fact that our motors suck. They were salvaged from a printer, and they just weren’t intended to exert significant force. They draw 100mA a pieace, which is enough to move a piece of paper, but not enough to pull a scroll very well. I mean, it moves, but really only at one speed: slow. This meas that the variable speed part of the design is pretty nonfunctional at the moment. Still, it does work, and I’m pretty happy with it as a proof of concept.
There’s a lot more work to do from here though. The obvious irst step s replacing the motor and gear assembly with one that can eet the physical demands of the device. I suspect that the next step will be the most technically difficult: running a barcode across the back of the scroll and rigging a scanning system on the device so that it can tell what section of the scroll is being displayed (actually we’ll probably need two readers, one at each end of the device, so that we can monitor the amount of tension on the scroll as well as allow for knowledge of display width if we have variable-width devices). Once that’s done a lot of new options open up: we can allow for “bookmarking” of sectionsof the scroll (local and possibly shared-across-the-net bookmarks), we can let the microcontroller automatically scroll through the scroll (either through specific scenes or simply throughout the entire length). Basically we can allow the scroll to become a traditional “hands-off” art object in addition to an interactive one. In addition to the additions in control hardware and software, there are some structural changes to make to te device. Three come to mind: first the light table made things look so much better that I figure that as long we have to power the device we might as well include a backlight, second we need to figure out how to handle wall-mounting the device as a means of display (this may mean lighter materials, but perhaps not), and third we need to figureout how we want to manage the input side of a much more complex device (go wireless with a remote control? eave it on the device directly even though it will take up more room and potentislly be more distracting?). Anyway, I’m still excited about the project and can’t wait to move forward.
Tags: physical computing