Léon Theremin built his eponymous instrument in 1920 under Soviet sponsorship to study proximity sensors. He later applied the idea of generating sounds using the human body’s capacitance to other physical forms like the theremin cello and the theremin keyboard. One of these was the terpsitone, which is kind of like a full-body theremin. It was built about twelve years after the theremin and named after Terpsichore, one of the nine muses of dance and chorus from Greek mythology.
Just when we thought we’d seen all the ways there are to tell time, along comes [mr_fid]’s Berlin clock build. It’s based on an actual clock commissioned by the Senate of Berlin in the mid-1970s and erected on the famous Kurfürstendamm avenue in 1975. Twenty years later it was decommissioned and moved to stand outside the historic Europa-center.
This clock tells the time using set theory and 24-hour time. From the top down: the blinking yellow circle of light at the top indicates the passing seconds; on for even seconds and off for odd. The two rows of red blocks are the hours—each block in the top row stands for five hours, and each block below that indicates a single hour. At 11:00, there will be two top blocks and one bottom block illuminated, for instance.
The bottom two rows show the minutes using the same system. Red segments indicate 15, 30, and 45 minutes past the hour, making it unnecessary to count more than a few of the 5-minute top segments. As with the hours, the bottom row indicates one minute per light.
Got that? Here’s a quiz. What time is it? Looking at the picture above, the top row has three segments lit. Five hours times three is 15:00, or 3:00PM. The next row adds two hours, so we’re at 5:00PM. All of the five-minute segments are lit, which adds 55 minutes. So the picture was taken at 5:55PM on some even-numbered second.
The original Berlin clock suffered from the short lives of incandescent bulbs. Depending on which bulb went out, the clock could be ‘off’ by as little as one minute or as much as five hours. [mr_fid] stayed true to the original in this beautiful build and used two lights for each hour segment. This replica uses LEDs driven by an Arduino Nano and a real-time clock. Since the RTC gives hours from 0-23 and minutes and seconds from 0-59, a couple of shift registers and some modulo calculations are necessary to convert to set theory time.
[mr_fid] built the enclosure out of plywood and white oak from designs made in QCAD. The rounded corners are made from oak, and the seconds ring is built from 3/8″ plywood strips bent around a spray can. A brief tour of the clock is waiting for you after the break. Time’s a-wastin’!
We should come clean right up front. We like blinky stuff, tech art, smoke machines, and dark atmospheric electronic music. This audiovisual installation piece (scroll down) by [supermafia] ticks off all our boxes. As the saying doesn’t really go, writing about site-specific audiovisual art pieces is like dancing about architecture, so go ahead and watch the video (Vimeo) below the break.
Necessity is the mother of invention. It is also true that invention necessitates learning new things. And such was the case on the stormy Tuesday morning our story begins. Distant echos of thunder reverberated in the small 8 x 16 workshop, drawing my attention to the surge suppressor powering my bench. With only a few vacation days left, my goal of finishing the hacked dancing Santa Claus toy was far from complete. It was for a Secret Santa gift, and I wanted to impress. The Santa moved from side to side as it sang a song. I wanted to replace the song with a custom MP3 track. In 2008, MP3 players were cheap and ripe for hacking. They could readily be picked up at local thrift shops, and I had picked up a few. It soon became clear, however, that I would need a microcontroller to make it do what I wanted it to do.
While most people who build their own computer from chips want the finished product to do something useful, there’s something to be said about a huge bank of switches and a bunch of blinkenlights. They’re incredibly simple – most of the time, you don’t even need RAM – and have a great classic look about them.
[Jim] wanted to build one of these computers and wound up creating a minimal system with switches and blinkenlights. It’s based on the Z80 CPU, has only 256 bytes of RAM, and not much else. Apart from a few extra chips to output data and address lines to LEDs and a few more to read switches, there are only two major chips in this computer.
With the circuit complete, [Jim] laser cut a small enclosure big enough to house his stripboard PCB, the switches and LEDs, and a few buttons to write to an address, perform a soft reset, and cycle the clock. One of the most practical additions to this switch/blinkenlight setup is a hand crank. There’s no crystal inside this computer, and all clock cycles are done manually. Instead of pushing a button hundreds of times to calculate something. [Jim] added a small hand crank that cycles the clock once per revolution. Crazy, but strangely practical.
[Jim] made a demo video of his computer in action, demonstrating how it’s able to calculate the greatest common divisor of two numbers. You can check that video out below.
A few old timers may remember that once, long ago, computers didn’t require keyboards. The earliest personal computers such as the Altair 8800 and the server rack-sized minicomputers like the PDP-11 could be controlled with a panel filled with switches and lights, giving us the term blinkenlights. Today, most of these machines have been thrown away or locked up in museums and private collections; even if you were to get your hands on one of these control panels, you’ll have a heck of a time doing something useful with one.
Fear not, because [Jörg] has come up with a great way to control these blinkenlights and simulate the computers of yesteryear. He calls his build BlinkenBone, and it’s able to control the blinkenlight panels from dozens of historical computers and simulate every thrown switch and tiny light bulb.
BlinkenBone is a BeagleBone single board Linux computer running the SimH simulator for antique computers. Right now the BlinkenBone is able to simulate the PDP-1, PDP-8, PDP-11, a lot of old IBM machines, the Altair 8800, and even some HP boxes.
Without a BlinkenBone or similar simulation device, the still-surviving control panels for these computers are just pieces of art to hang on a wall. When they’re running a simulation of their original hardware that was long-lost to the scrap yard, they become the useful devices they once were. Also, it’s much easier to appreciate how far technology has come in the last 40 years.
You can check out a short demo of [Jörg] using his BlinkenBone on a PDP-11/40 after the break. Look at those lights go.
Because surplus LED panels from an early 1990s supercomputer is a completely reasonable thing to own, [William Dillon] set to work displaying them on his wall.
The LED panels came from a surplus CM-5 Connection Machine, best known from it’s role as the mainframe in Jurassic Park (only an empty case with LED panels were used in the movie). When not on Isla Nublar, the Connection Machine was a fabulous piece of engineering from the 1980s Artificial Intelligence revival. With some machines having 65,536 processors, it was used for AI research using Lisp (although we were never very good at Lisp.
[William] built a wooden frame out of 1×2 inch maple and installed an X10 module behind the panels as a remote switch. The panels themselves aren’t controlled by a computer, so the only thing left to do was to mount the power supplies. It’s impressive to see the massively over-engineered power supplies that were designed to source 5V @ 30A when the panels only draw 7 Amps. [William] says it was a design feature of the Connection Machine to spare no expense.
[William]’s next plan is to reverse engineer the panels to display custom messages, and we can’t wait to see what he comes up with. We can’t explain why, but we really want to build one of these panels. Check out the pictures of [William] decommissioning the CM-5.