Interactive poster exhibit

Permanent installation at the National Cowgirl Museum in Texas, through West Office Exhibition Design.

Visitors create their own mock movie posters by selecting a poster design from a button on the wall, then standing in front of a greenscreen. A monitor facing the visitor acts as a mirror, allowing them to position themselves against the background; a monitor facing outward shows the same thing to other visitors. After a countdown (visual and audio), the picture is snapped and a barcoded receipt is printed, which can be taken to the museum shop to purchase a printout. There are five poster designs, each designed to appeal to single or multiple, male or female, visitors.

This exhibit runs on a Powermac G4, with buttons hooked through a BBI show controller via serial RS-232. A small JVC digital video camera feeds into the computer's Firewire port, and a flash also is triggered through the show controller, though for effect only. Everything takes place in Director, with live video compositing accomplished with Danny Rozin's VideoMask Xtra, still frame export with Herb Diamant's f3qtEdit Xtra, and receipt printing (complete with 1-bit thumbnail-sized poster) done with the Print-o-matic Xtra. The computer deposits the snapshots on an iMac in the shop via Appletalk over TCP/IP, where another Director program allows barcode scanning and simple searching through 30 days worth of images. It prints 5x7 images on an Epson 1280 Photo printer, using the Print-o-matic Xtra.

Dan Cummings wrote the code and we began testing right away. We considered still cameras, or doing the compositing with special hardware (such as a Videonics mixer), but decided on the VideoMask Xtra because it gave us maximum flexibility and customizability, and we were familiar with Danny Rozin's excellent work. (We tapped Danny later in the project to add DV capability and mirroring to his Xtra.) We selected the $800 JVC GR_DVP3u camera for its manual settings and small size, though various cheap Firewire webcams would work just as well. The VideoMask Xtra has a lot of parameters to tweak, but lighting of the greenscreen still proved important. (Originally a bluescreen, it was switched to green due to the prevalence of blue jeans in Texas!) The monitors were to be mounted vertically, so having everything turned sideways proved an additional challenge during programming and debugging. And to make the monitor act as a mirror, we had to flip everything horizontally, then flip it back after the picture is snapped so that actual orientation is preserved and printed t-shirts for example don't appear backwards.

With a lot of interconnected hardware and processes, we tried to simulate the exhibit conditions and test all of the pieces independently and together. West Office has a nice, big former factory building and a full shop, ably run by Jim McGee who put together a nice greenscreen setup. The G4 and show controller proved perfectly capable. In our mockup we used a Keyspan adapter to convert serial to USB, but we encountered problems between it, Director, and the USB printer, and on-site we switched to a Stealth Serial Adapter, (long ago recommended to me by Mac guru Steve Godun). Keyspans and their ilk have a notorious problem that they have to be reset periodically by unplugging and plugging back in; the Stealth has no such problem, being a 'real' serial port.

The Dymo printer also proved unstable under constant usage, with paper jams and USB conflicts. We ditched a (CAT 5) USB extender cable, and barely had enough room to run a direct, 14-foot USB cable after Maltbie quickly and seamlessly made a channel in the floor. Finally, we switched to a Ithaca POSJet, designed for more rugged retail use. The print quality is not as sharp as the Dymo, but the paper rolls are cheaper and easier to change. After we swapped the adapter and printer, most of our problems went away.

Here is a test composite, one of many dour and poorly-lit shots of me staring at the computer screen, and a test thumbnail print. The initial poster designs I did here were later made beautiful by April Banks at West Office.

The instructions were distilled down to three simple steps. Testing with the mockup caused us to switch steps 2 and 3. Pressing a button in step 1 starts the countdown, and having the visitor take the ticket first caused them to spend more time at the instructions. Plus, the ticket would appear in the picture. Now they push a button, go immediately to the screen, then pick up their receipt on the way out. Because space was fairly tight, we removed a separate exit, so the visitor enters and exits through the same gate.

All the AV hardware sits in a crate on the floor, visible in the photo above.

Meanwhile, down in the gift shop, the iMac was chosen for its small footprint, and our goal was to avoid a mouse and keyboard to save additional counter space, confining ourselves to a barcode scanner and small numeric keypad (which I velcroed to the iMac). The iMac, thankfully, has one more USB port (3 total) than the G4. It is a sharp visual contrast to the cash register PC, with its cash drawer and CRT monitor. We did not attempt to link the two systems.

The Epson printer has decent print quality, but takes at least 30 seconds to print, and during the packed opening weekend this caused up to a two-hour wait for printouts. A purportedly faster HP was hastily purchased, but did not prove much faster, and its print drivers were not as customizable; even with the Epson, it was hard to get the printout simply to be centered on the page, without some manual adjustment by the staff, nearly foiling our goal to go mouseless. But we went back to the Epson ultimately. It is inexpensive and thus easily replaced, but of course the museum goes through a lot of ink and paper.

Dan coded in some nice searching and error-checking features. The poster software sends an image every time it snaps one, and the shop software checks for new ones every 30 seconds. He brilliantly coded Director to make custom barcodes (specifications for them are freely available online.) Barcode scanning a ticket immediately brings up the right poster, or if it can't find it, goes to a visual search screen. I stuck with a minimal screen design, and added some archiving capabilities - every night the computer moves the day's images to an archive folder, and deletes images more than 30 days old. Everything starts up and shuts down automatically. Maintenance and updating are intended to be automatic since the museum has no technical staff.

Further information including technical details are here.