Since tonight is the opening party of this year’s Club Transmediale and a lot of people will see our installation “I Am Display” and the technology it is based on, “Display2000”, for the first time, I want to reactivate this blog to tell a bit about it from my own viewpoint , which is the technical side of the piece. This article will grow as I manage to collect the information, so check back later for images, videos, schematics and software.
I was asked to join an interesting project by Mendel, a designer I briefly talked to on one of our Baustel mondays, on November 6th. He was one of the experts who made suggestion on the possibility of realizing the projects the residents of Palomar5 had been working on, one of which being a big alphanumeric display consisting of fluorescent tubes. He saw that they needed someone with a bit of experience to help out and asked me to join them.
When I came into the camp, Valentin show me his design, adopted from the circuitry of a plug-in timer, and told me that he had already ordered the parts: Shift registers, darlington arrays and mechanical relays. I told him that I would do the switching with solid state technology, but since the time was already short (two weeks to go until the final presentation), I agreed to make the printed circuit boards for the parts.
The first prototype PCB was ready on the next day. It had all relays on the board and worked fine for just a few tubes, but the dirac pulses passed through the driver IC into the digital part and caused wrong outputs as soon as you tried switching many lamps at the same time.
So we tried optimizing the design while keeping the same parts: Moving the relays into the metal lamp fittings and giving each one a snubber. We also prototyped this and it looked quite promising. So we went into production: Building all ten wooden frames, installing the fittings, putting the relays with the snubber in, cabling, installing the PCBs (we even got professional cast aluminum housings for them). But still, when there were too many lamps being switched at the same time, strange things happened. So, for the Palomar5 summit, the Display2000 wasn’t finished. But while I tried making the best out of it and working on it for dozens of hours, I had the idea of putting the logic as near to the lamps again and do all the data transmission over a really solid bus, the DMX bus.
Since the summit was over now and we didn’t have any pressure, we scratched all the electronics and restarted with a whole new design. We based it on an DMX512 dimmer circuit and first built 5 prototype boards and, when we saw that it did really work, made 24 additional ones (this time ordered them from a professional PCB manufacturer instead of etching and drilling them myself), recabled everything and now, it is up and running as can be seen in the exception. From my time, around 240 hours went into it, in total, the whole team must have sank more than 1000 hours. But the end result is really worth the effort.