This all came about as part of an on-going wager Ed has with a co-worker, which has evolved into a challenge to create an electronic computer using only technology existing prior to 1900.
This really is rather cool. Thus far, Ed has managed to create neon-based implementations of all the primitive logic functions (AND, OR, NAND, NOR, etc.) along with a D-Type flip-flop. He also has a neon-based ring counter running, which he intends to use as the basis for his system clock.
When Ed saw my articles, he became enthused with the idea of creating the HRRG out of his neon logic. But there are many aspects to this, such as creating larger, longer-term storage elements. There are a number of possibilities here, but Ed is determined that everything to do with his HRRG realization be based on some form of optical / light technology.
Anyway, I just received the following update with regard to Ed's current investigations into optical storage...
I have been pondering methods to display information for a HRRG (Heath Robinson/Rube Goldberg) Computer in recent days (Click Here to see Max's article that triggered all of this).
One thought I had was "How about 'writing' patterns of dots to phosphor paint on a conveyor belt using a scheme similar to a POV (persistence of vision) LED array?" This sounds like it could also be used as a display in some fashion. Surely somebody must have tried something link this already.
A quick Google search turned up some real beauts. The oldest instance I was able to find was a spectrum analyzer circa 1946 for analyzing the human voice (Click Here)
The idea is that we have a microphone (shown on the right) whose output is fed into a bunch of different filters. The output from each filter controls a light. All of the lights are located over a moving belt covered in phosphor. So different words and sounds spoken into the microphone are converted into corresponding patterns in the phosphor, which keeps glowing for a while.
Of course, this wouldn't be an article written by me without at least one Wikipedia link (Click Here to see the Wikipedia entry on phosphorescence).
I found a two or three phosphorescent moving media displays Googling around. In this article, I decided to feature something called the “Temporal Scroller.” Nenad (aka bgrgyk on YouTube) was kind enough to fill me in on the details. Nenad writes as follows:
I am from Serbia, and will graduate in a few months from Racunarski fakultet (School of Computing –http://eng.raf.edu.rs).
I'm interested in pretty much anything (except sports perhaps :)) Before I started programming I was a kid who liked to draw and break things apart to see how they work.
The inspiration for the “Temporal Scroller” came from a video I saw few years ago where some guys made a similar thing with a gramophone/turntable which was covered with phosphorescent material and the needle head was replaced with an LED. I kept the idea in my head for the following years until I had an upcoming university project, which was a perfect opportunity for finally making it.
The idea was to have the whole thing mounted on a wall and display tweets, weather data and whatnot, but it didn't really turn out that good. The belt deforms after some time, starts slipping and has to be nudged by hand. The motor was annoyingly loud.
Regarding the video, we didn't get to capture the whole thing in a frame and all you really see are close-ups. I'm not sure that viewers can get the whole picture, but the thing was 50cm in length. Unfortunately that expensive phosphorescent material I was lucky to have found was so crappy that it fades out after a minute. However it was perfect for this purpose.
After enough people had seen it, it was disassembled because I had to return the development board to the university. It might get another revision in the future, but I'm more hyped into building a quadcopter or a Hektor-like contraption now :)
Editor's Note: Click Here to see see Hektor the Spray Paint Output Device, a Portable Drawing Machine for Walls
Overall I was happy how my project turned out and wasn't so sad to have it disassembled. A few days later I found out about the Buddhist ritual of sand mandala (Click Here), which the lifetime of my scroller resembled.
Some details on the implementation Electronic Hardware:
Eight white LEDs (I couldn't find UV, but it turns out blue, purple and white [which contains those frequencies] work just as good)
PIC16F887 microcontroller (on a Mikroelektronika EasyPIC6 dev board that we used in that class at university)
Stepper motor from an old printer
Driver for stepper motor
Phosphorescent sheet (bought in a printing supplies store, they sell it by meter and it's expensive as hell but I only needed 1m x 20cm which was around $15)
The conveyor frame was made out of some industrial aluminium parts (used for making racks/shelves I suppose)
Belt was spanned onto two rolls from printer toner
Motor to phosphorescent belt from a VHS player
Pulleys were made on a lathe
I made a Flash app that sends plain text to a TCP socket that's connected to program called "serproxy" – serial proxy tool that relays data from socket to a COM port and vice versa.
The microcontroller code is written in C, it buffers the text it receives, takes care of the timing for writing the LEDs and driving the motor. I used MikroC, IDE and compiler suite which comes with that EasyPIC6 board.
Since I was always interested in visual stuff I was immediately attracted to Flash when I first saw it. Flash has been my tool of choice for many years since. Right now I'm steering away from it, looking into stuff like functional programming, Haskell, Scala, LISP.
You'll see in my video the Flash app running on the laptop with debug line that resembles the real thing, decontrolling echoes the byte value of the LEDs back to Flash (Click Here to see the video on Hack-a-Day or Click Hereto see it on YouTube).
Nenad's project is a good lesson in several engineering disciplines and philosophy all rolled into one. He certainly gets a glowing recommendation from me.
For my part, I am going to try the POV (persistence of vision) LED trick interfaced to a rotating drum painted a ghostly phosphorescent green. Here is a POV LED example from a comrade in arms in the Twin Cities Maker and DIY community:
Maybe in addition to a display I can fashion a sort of dynamic read writable memory device. Reading arrays of glowing dots just prior to fading out may be a little tricky but it certainly would be a sight to behold as part of an HRRG computer.
About the author Ed Vogel is an electrical designer at Medtronic Cardiovascular working with the instruments group on how to move teeny tiny things without touching them and know where those things are without seeing them.
Prior to Medtronic, Ed has been a plank owner in start up companies ranging from PCR gene amplification to high pressure fuel injectors.
Ed has also been a feature author with MAKE magazine and provided program support for the "Make: television" show by TPT.
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