Metropolis Time

In an earlier rambling, I introduced the Metropolis Oscilloclock, themed after the classic 1927 science fiction movie. The clock seems to have garnered some attention, and thanks to the kind folks over at Hackaday, I now have two additional facts to relate:

  1. The “Maria” robot in Metropolis inspired the design for C-3PO in Star Wars!
  2. Some folks have considered the Workers’ clock to be Decimal !

The first point stands without dispute, but let’s take a closer look at this “Decimal” aspect, as I’d never considered it before.

Decimal Time vs. Metropolis Time

Below is what got folks interested – the 10 hour clock face. The Masters used this to dupe the Workers into believing they were working short shifts, when in fact they were slaving away for a full 12 hours. Ingenious!

But this is not Decimal Time, where time is divided into units that are purely decimally related. Yes, there are 10 hours on the face, but there are 20 hours per day, and 60 minutes to the hour. And, if you bother to count the dots around the edge, you can see there are 72 seconds per minute. None of these are decimally related.

Speaking of decimal time, I fondly remember a Metric Clock article in the April 1987 edition of Electronics Australia. Being but a wee lad at the time, I was gullible enough to believe that true Decimal Time was going to be introduced in Australia imminently. I ‘convinced’ my father (he led me on) that it was really happening, and I was just about to purchase the kit to build my own Metric Clock… when in the following month’s edition, the magazine came clean that it was actually an April Fool’s joke!

But enough fooling around – let’s now take a closer look at the Oscilloclock implementation of Metropolis Time…

Metropolis Time vs. Regular Time

The two clocks in Metropolis differ only in one way: the length of an ‘hour’. This is easy to grasp, since there are 20 hours per day in one, versus 24 hours per day in the other.

But from here, Metropolis messes with your mind! Below are some revelations that [Andrew] and I battled over numerous e-mails to come to terms with:

  • The hour hands on the 10h face and the 12h face must always be exactly aligned (they must go around at the same speed).
  • Since an M-time hour is 20% longer, the minute hand must go around slower.
  • To make the M-time minute hand go around slower, the second hand must also go around slower.

Even if this makes sense so far, the crunch comes when you think about how to implement it. If it were a physical clock, the tick speed could be slowed and the gears could be modified to make the seconds and minutes go slower but the hour hand itself move at the same speed. Easy!

But it’s not a physical clock, and in the current Control Board design, the tick speed is NOT readily adjustable as it is derived from the MCU clock, which all the critical display routines are optimised around. So essentially, the length of a second cannot be changed.

Without changing the length of a second, how can we make the minute hand go around 20% slower? Well, there are only two options:

  1. Have 72 seconds per minute, with 60 minutes per hour
  2. Have 60 seconds per minute, with 72 minutes per hour

We decided on the first option, and you can see from the video below that the second hand indeed moves through 360 degrees in 72 steps (actually half that, since there is a half-tick).

An interesting tweak here is the shape of the hands. Note that they have triangular outlines, to more accurately mimic the hands in the film. But computing the angles and projecting these outlined hands using Circle Graphics was a true challenge – especially as the current Oscilloclock firmware is written 100% in PIC18F assembly code! Assembly is great for optimizing timing, but with no maths related processor instructions or functions to leverage, this feature was a huge effort…

Why assembly code? Just because I can!

Digital Metropolis Time

Everything was now all fine and dandy for the analogue 10h clock face, but what about all those nice digital faces that are stock standard in every Oscilloclock? Could I make Metropolis Time make sense in a digital format as well?

Of course! Except there was one hitch. Since we have 72 seconds per minute, the clock would show times like 09:16:65. This would look odd. Andrew wanted to keep the seconds in the range 0-59, like in a normal clock. Something would have to give… but what?

The answer was to simply ‘ignore’ one second in every six; i.e. the 5th second shows for 2 seconds before incrementing. This is easiest illustrated with another video (note what happens at the 10:57:55 mark):

But easiest of all is to see this in Excel. The duplicate second is highlighted:

Switching between Metropolis and Regular Time

Now, let’s face it: Metropolis time is really not very useful in day-to-day life; not for us Masters. Andrew wanted to be able to revert all faces at will to show Regular time instead of Metropolis time (except the 10h analogue clock face).

This was duly implemented during production of the 2nd Metropolis Oscilloclock – which will be presented in an upcoming post. Stay tuned!


If, like me, you are hopeless at simple time zone conversions but you’ve actually managed to fully get your head around the above, Congratulations! Stay tuned for more posts in the Metropolis series.

Metropolis Mania!

Oscilloclocks are special. Oscilloclocks are unique. We know this. But in November 2015, a request for something exceptionally special and unique arrived from [Andrew] – he wanted me to craft a Metropolis movie themed timepiece!

Metropolis Movie PosterMetropolis is a classic science-fiction silent movie created by Fritz Lang in 1927. It’s an amazingly beautiful film with a fascinating plot, passionate acting, and attractive futuristic props and architecture heavily influenced by the Art Deco and other artistic movements. (Haven’t seen this movie? Watch the newly reproduced full version here!)

Well, Andrew was building a very large space at his home dedicated to the Metropolis movie. It would be a full-on “man cave”, with a lounge/bar, music and video venue, mad scientist lab, and collection display space. The mad scientist part of the building would house various scientific demonstrations based on vintage physics or chemistry experiments, with a dose of mad science thrown in.

Andrew was collecting themed art and memorabilia for his man-cave, and had even commissioned a full size ‘Maria’ robot (#3 in the world) from the licensed manufacturer…

But there was one thing missing – a Metropolis 10-hour clock.

Metropolis Time

In the Metropolis movie, the Rulers enjoy their lives in normal time, but the Workers are forced to perform their heavy-labour duties in 2 shifts of 10 ‘worker hours’ each day. The Workers’ clocks are thus labelled with only 10 hours.

Metropolis clocks for Rulers and Workers

Metropolis clocks – Normal time for Rulers (top), but 10-hour time for Workers (bottom)

The 10-hour clock features in multiple scenes throughout the movie, as clear symbology that the controlling and oppressive Masters can even manipulate Time – if only on the surface!

In this scene, Freder struggles with the clock machine...

In this scene, Freder struggles with the clock machine…

[Andrew] wanted to commission an Oscilloclock that would display an authentic 10-hour Worker clock face with accurate hour, second and minute hand movement, as well as the normal 12 (24) hour Ruler clock faces. He also wanted all numerals and characters rendered in the Metropolis font. This could be THE talking piece of the man-cave!

Presenting… the Metropolis Oscilloclock!

After 8 months of discussion and development, the first Metropolis Clock was finally delivered. This unit is based on the same beautiful Toshiba ST-1248D vintage oscilloscope model used in a previous conversion. However, it incorporates some wonderful new features, including LED-backlit valves and an external input feature to support Lissajous figures generated by an iPhone or other device!

The Metropolis Clock - Toshiba ST-1248D - 01

Metropolis Clock - 06

Artwork on the splash screen evokes an image of the skyscrapers in the movie poster…

The clock keeps both 'normal' and Metropolis 10-hour time!

The clock keeps both ‘normal’ and Metropolis 10-hour time!

Realistic LED backlighting - enjoy the valves without actually heating them up!

Realistic LED backlighting – enjoy the valves without actually heating them up!

To be continued…

Each of the new features built out for this exotic creation deserves a post on its own. Stay tuned for many more pictures and information about Lissajous inputs, backlit valves, and Metropolis time switching!

Also, careful readers would notice my use of the phrase “first Metropolis Oscilloclock”. Andrew was so delighted with the Toshiba ST-1248D unit that he commissioned a second Metropolis clock with even more firmware enhancements, based on the Tektronix 520A. Another topic for another day!


See the Metropolis Archive for all other posts in this series!


Like what you see?

Metropolis is just fantastic as a theme for a custom Oscilloclock. But if you have a different passion that needs horological augmentation, let me know!

X-Y-Z Core – Revamped

Avid followers may have noticed an absence of fresh posts recently… What gives?

I’m happy to report that it’s only because Oscilloclock has been absolutely run off its feet in 2016, producing more crazy CRT based devices than ever before. There just hasn’t been time to do justice to the blog!

The good news here is there are lots of posts in the backlog. Let’s start out with this one:

Yet Another CRT clock fanatic?

I was approached by [Mike], who wanted to design his own CRT clock from scratch, but didn’t want to mess with the high voltage circuitry involved. Could I help out with an X-Y-Z display assembly, and he would do the rest? You bet!

Here is the newly revamped Oscilloclock X-Y-Z Core, shipped out in Q2 2016:

Oscilloclock XYZ Core

And here is what [Mike] was able to with it, after implementing a totally fresh controller design incorporating Circle Graphics:

oscilloclock-xyz-core-customer-clock-implementation-01

[Mike]’s setup – A home-grown controller board, the X-Y-Z Core, and a 3KP1(F) CRT

Here is [Mike’s] story in his own words:

I was thinking of building a Nixie clock, but when I discovered the vector graphic clocks that Aaron and others had built, I knew I needed to build one. I felt comfortable that I could recreate my own version of the digital logic and the low-voltage analog signals, but didn’t really want to tackle the deflection amp or the high voltage circuitry. Buying the Oscilloclock XYZ display solved that problem. Everything arrived as and when promised, and I was beyond impressed by the care and workmanship that’s evident in everything from the boards to the harnesses to the documentation!

I based my controller board on a Cypress PSOC 5LP chip, which allows me to implement all of the digital logic in its on-board programmable logic fabric. The 80MHz 32 bit ARM processor allows me to program 100% in C, which enabled me to create my own version of the software fairly easily. (I tip my hat to those who have done it all in 8-bit assembly!)

Remaining work includes improving my signal quality, which doesn’t yet fully exploit the bandwidth and linearity of the Oscilloclock boards, designing an interesting enclosure, and adding a few software features.

Good luck [Mike] with the rest of your implementation!!!

Key features

This unit is the latest incarnation in a series started in 2015, for a client who needed a custom Head Up Display solution. The boards have undergone through several revisions since then to optimize performance. This particular kit was pre-configured and fully tested to support 3RPx, 3KPx and 3WPx CRT types, and features:

  • Cathode to deflection voltage of 1875V
  • Digital blanking (grid modulation), safely isolated at 2.2kV continuous working voltage
  • Precision deflection amplifier capable of driving +/- 275V with 0.1% linearity
  • 0-5V analog X and Y inputs with 2.5V reference output [Option RS]
  • TTL/CMOS compatible high-frequency blanking input
  • Dim/Bright digital input with PWM support
  • Power Off digital input
  • Temperature-controlled fan with Failure and Overtemp safety features
  • CRT rotation coil supply (+/-5V)
  • CRT heater soft start / inrush current limiting
oscilloclock-xyz-set-16001-01-01

Oscilloclock X-Y-Z Core set – as shipped


Like what you see?

X-Y-Z displays are cool. But so are my other unique creations! See the Gallery, and stay tuned!

Kikusui Time

Time – the universal constant. Time passes the same for all peoples; rich or poor, busy or idle, inspired or dispirited. And time has certainly passed for Oscilloclock.com since the 2015 Tokyo Maker Faire – the event that just keeps giving!

At last, we present the final model from that Faire – the Kikusui 537 Oscilloclock!

Kikusui 537 Oscilloclock

See this in HD, and find more exciting videos on my YouTube channel

The Kikusui 537 was hand-picked for conversion by the lab’s youngest technician (9 at the time). He chose it for its small size and portability, but also for its cute colour scheme! A dainty red sweep adjustment knob highlights a bright white and black control panel, with a blue case providing overall contrast and visual soothing.

Kikusui 537 Oscilloclock

The 537 Oscilloclock’s small size makes it the perfect clock for an office desk, bedside table, or mantle. And since this is a ‘maximum re-use’ conversion, the existing circuit is active and all the front panel controls are fully functional. Fiddle with the image’s size and position to your heart’s content! Switch from XY mode to normal sweep mode, to view raw Oscilloclock signals in real time, as the seconds tick by!

History

The 537 was manufactured by Kikusui Electronics Corp., a major producer of test equipment in Japan since 1951. It was produced in large numbers from 1975 and was extremely popular for its small form factor, solid-state design, 5 MHz bandwidth, and ‘low’ price of 45,000 yen (perhaps USD 1,000 in today’s terms). See the catalogue page (Japanese only) and the operating manual (Japanese and English).

Kikusui Logo

The Kikusui Electronics Corp. logo

Construction highlights

In a previous post, I mentioned there are several general approaches to converting an oscilloscope. Since the Kikusui 537 is fully solid-state (it uses transistors instead of valves/tubes, except for the CRT) and it is only 40 years old, I decided on the maximum re-use, minimal invasion approach. (I really should trademark that term!)

This approach involves tying the Oscilloclock Control Board‘s outputs directly into the existing X and Y amplifier circuits. This was easy to do in the 537!

Kikusui 537 Oscilloclock - inside top

Oscilloclock Control Board mounted in the 537

However, as discussed in the Circle Graphics post, we also need to be able to blank the beam at extremely precise intervals. Sadly, the 537 (like nearly all oscilloscopes of this vintage) does NOT have a convenient DC pulse-tolerant Z-axis input. I therefore installed an Oscilloclock Power Board, partially populated to serve as an isolated blanking amplifier, in series with the grid.

Partially populated Oscilloclock Power Board

Partially populated Oscilloclock Power Board

Finally, an Oscilloclock Supply Board was needed to power the other boards.

An Oscilloclock Supply Board is also nestled in there!

An Oscilloclock Supply Board is also nestled in there!

Mounting the Control

What better place to fit the rotary encoder, than on the beautiful red sweep frequency adjustment knob that my junior technician liked so much! Here’s the general story:

Kikusui 537 Oscilloclock - control (original)

Sweep adjust control in its original state

After removing the potentiometer

After removing the potentiometer

The encoder, after hacking with a hacksaw!

The encoder, after hacking with a hacksaw!

Kikusui 537 Oscilloclock - control mounted

Voila – sweep knob now drives the rotary encoder!


Like what you see?

One of the two Kikusui 537 Oscilloclocks crafted for the Maker Faire is still available for the special person with a soft spot for a krazy kikusui klock. Visit the Availability page for more information, and of course see the Gallery for other unique creations!

The Oscilloclock Core

Over the years, folks out there have reached out to me with all sorts of crazy ideas about cases and housings for scope clocks and custom CRT displays. Here are some interesting examples:

  • The console of a vintage pipe organ
  • An ancient grandfather clock
  • A cylindrical case made of some exotic wood
  • A “cathedral” style vintage radio

Essentially, these people wanted just the innards of an Oscilloclock, which they would build into their own case. Could I help out?

Absolutely! For people who want to roll their own cases, and who have experience handling high voltage electronics and CRTs, I occasionally prepare custom board sets that are lovingly hand-assembled, tested, and tweaked for optimum performance with a given CRT. Here we go:

The Oscilloclock Core

Oscilloclock Core, hand-crafted in 2015 for a discerning customer in Germany

An Oscilloclock Core, hand-crafted in 2015 for a discerning customer in Germany


The standard Oscilloclock Core layout, on a test acrylic mounting

The standard Oscilloclock Core layout, on a test acrylic mounting

I supplied this particular unit with an 8SJ42J Chinese-made CRT, just for testing purposes. This is a 3″ PDA tube with a highly restrictive rectangular viewing area, but the customer found it just great for checking things out!

Oscilloclock Core - complete set for 8SJ42J - 03Oscilloclock Core - complete set for 8SJ42J - 06
Oscilloclock Core - complete set for 8SJ42J - 02

What comes with it?

Here’s what’s comprises the typical Oscilloclock Core:

  • 1 x Fully assembled and programmed Control Board (optional on-board GPS)
  • 1 x Fully assembled Deflection Board (latest ultra-linear revision)
  • 1 x Fully assembled Power Board optimised for a given CRT (latest revision with options: onboard high-bandwidth blanking amplifier, rotation coil supply, auto fan speed control, unblanking plate modulation, and isolated bright/dim input)
  • 1 x Fully assembled CRT Board (optional; an external blanking amplifier recommended when the CRT cable is longer than 50cm)
  • 1 x Rotary encoder
  • 1 x Worldwide 9V power supply (high quality wall wort unit, commercial ratings)
  • 1 x Garmin GPS unit with 5m cable; wired to board-side connector (not required for onboard GPS)
  • 1 x Set of standard inter-board and CRT harnesses for testing and reference (10kV/3kV silicone melt-proof used for HV cables, other LV cabling also heat-resistant)
  • 1 x Cast acrylic test mounting assembly, fitted with the boards, ready for testing out-of-the-box with your CRT
  • 1 x Ceramic adjustment screwdriver
  • Service documentation (schematics, board layouts, complete Digikey BOMs, harness specs)
  • All components are latest available types sourced within the last 6 months, 0.1% or 1% tolerance resistors, minimum 2 x rated working voltage capacitors, all lovingly hand-mounted by myself
  • All boards sprayed with HV lacquer for moisture and arcing protection
  • 2-week satisfaction guarantee. But no long-term warranty on board-only purchases

Naturally, the lengths of all harnesses and inter-board cabling can be customized according to the owner’s requirements. And there is also an Oscilloclock Core Cube arrangement, where the boards are stacked to reduce the length and width of the overall unit.

What CRTs does it support?

The Power Board and Deflection Board are increasingly flexible with each revision, but I insist on performing all configuration of the Core here in my lab. This allows me to tweak for maximum performance, and provide a proper satisfaction guarantee.

Typically I work with the owner to recommend a CRT based on preferences such as size, colour, and aesthetics. However in cases where the owner already has a CRT in mind, and I don’t have the particular CRT or a close equivalent, I ask the owner to send me one to test against. Or, I simply procure one; after all, one can never have too many CRTs!  (Though my better half does not agree…)

The current Oscilloclock Core board revisions meet the following operating parameters:

  • Maximum cathode to deflection voltage of 2175V
  • Maximum accelerator voltage of 3525V for PDA type CRTs
  • 6.3V heater, max 0.7A
  • Support for “Deflection Blanking” CRTs (see treatise here)
  • CRT rotation coil supply (+/-5V)
  • Precision deflection amplifier capable of driving +/- 275V with 0.1% linearity

Like what you see?

Check out the Availability page for more information, and of course see the Gallery for some unique CRT creations – many with an Oscilloclock Core at their heart!

More 2015 craziness – the CopperClock!

Happy New Year! Looking back, 2015 was a superb year, full of fun and fancy. And just in case you thought last year’s creative juices were exhausted by the fabulous Oscilloblock, rest assured that there was an even crazier creation – the 2015 luxury edition CopperClock!

CopperClock on shelf 01

The unusual facade for this unit was built to order by a Canadian craftsman specializing in hand-hammered and silver-soldered copper weather vanes. If you enjoy metal art, you will certainly approve of this!

Oscilloclock CopperClock 01

But… you may have read my previous articles and know that three-inch Oscilloclock models are typically powered by 2.1kV high voltage power supplies. Isn’t there any danger in using a metal case?

Never fear! The internals are fully encapsulated in a beautiful cast acrylic case, providing full insulation and utmost safety.

Oscilloclock CopperClock - internals 01

Breaking from tradition, I’ll refrain from describing other features of this unit (such as the selection of a round-faced CRT to give it character), and instead just post a few more photos of the clock ‘in situ’. Enjoy!


The 2015 CopperClock atop a beautiful Philips Radioplayer. What a match!

... or perhaps atop a vintage Estey pump organ?

… or perhaps atop a vintage Estey pump organ?

... perhaps it looks best on a 1920's Edison Diamond Disc Phonograph!

… perhaps it looks best on a 1920’s Edison Diamond Disc Phonograph!


Like what you see?

This exquisite specimen is currently available to someone with a metallurgical and chronometric disadvantage. Visit the Availability page for more information, and of course see the Gallery for other unique creations!

Presenting the Oscilloblock!

Ahh, summer – it’s well and truly over. But one person in the world is able to enjoy the warm, cheery feeling of summer every single day: the proud new owner of this beautiful OscilloblockSummer Dusk edition!

Truly the best thing to come out of the lab this summer – the Oscilloblock!

The Exterior

This playful timepiece features a Lego art case, painstakingly designed and constructed by Oscilloclock lab’s junior technician from a whopping 548 brand-new Lego parts sourced from around the globe. No expenses spared! Even the control knob is actually a Lego Technics gear. And just in case the owner wanted to take it apart and build it all over again, we included a 140-step Lego building guide in the package. Good luck!

Oscilloblock - Lego building instructions collage

The Oscilloblock features a good-looking 1970’s 3-inch (75mm) flat-faced CRT from Toshiba, with the iconic scripted logo in great condition on the base. At the rear is a scarce brown bakelite CRT socket, which are very hard to find complete with the rear insulating cap! The harness consists of tough 3kV tolerant silicone-sheathed cabling, shielded over most of its length to reduce electromagnetic interference.

Oscilloblock Summer Dusk edition - rear view

Wow, these vintage bakelite CRT sockets are hard to find!

Oscilloblock - a beautiful vintage Toshiba CRT

No doubts about authenticity!

One design goal was to have more than 90% of the CRT’s surface area completely exposed for viewing and touching, as opposed to encasing it in acrylic. Borne from this was a tremendous achievement for 2015: a new CRT ring support structure!

Oscilloblock - Beautiful CRT Rings

Acrylic rings with super-tiny pocket holes… cast and machined in Japan!

Internals

The internals of the clock are equally exquisite. A set of latest-revision Oscilloclock control, deflection and power boards drive the CRT at 2.1kV, providing a crystal-clear, ultra-bright trace. And of couse, every figure and character is generated using silky-smooth Circle Graphics.

Oscilloblock - side by side

The CRT assembly simply lifts away for showing off the internals! But DON’T TOUCH

Latest-revision boards.

Latest-revision boards. 250+ components. All hand-mounted!

On-board GPS for accurate timing - anywhere in the world!

On-board GPS for accurate timing – anywhere in the world!

Operation

There is only one control. It’s intuitive. It’s fun. It’s simple! Visit my YouTube channel to see various Oscilloclocks in operation.

But not everything is obvious, and Oscilloclocks all ship with an Operation Guide, with content specific to each and every unique unit. Here’s a snippet from the Oscilloblock’s guide:

No Oscilloclock model ships without a decent Operation Guide!

No Oscilloclock model ships without a decent Operation Guide!


Like what you see?

There’s really no limit to what can be done with a CRT and an idea! It was my son’s idea to use Lego, and he is proud to know there is nothing in the world quite like this Oscilloblock. See the Gallery for other equally unique creations.

Everything begins with an idea…

New Models at Maker Faire Tokyo!

The rainy season is officially over, and the long heat of summer has taken command. But here at Oscilloclock.com, we plan to sweat it out in air-conditioned comfort at…

Maker Faire Tokyo 2015!

Visit our booth and check out several new models! First up is the fabulous 2015 edition Oscilloblock. One unit will go on sale at the event!

Continue reading

Heads Up!!

Recently I received a most intriguing request: I was asked to build a self-contained, super-bright X-Y display unit with 3-inch CRT, for use in an “HUD“. Hmm…

Holographic Utterance Device?
Horizontally Unstable Doohickie?

Fortunately, I didn’t need to guess any further. As I was once an avid flight simulator enthusiast, I quickly hit upon the correct meaning: Head-Up Display. This is a mechanism that overlays instrumentation or map data onto the view looking forward from the cockpit, so that the pilot doesn’t have to look down to see this information.

HUD in an F-18 aircraft. Source: AC Aviation Life

HUD in an F-18 aircraft. Source: AC Aviation Life

Wikipedia has a great introduction to HUDs and their history, but Mike’s Flight Deck has the definitive tome for flight simulator enthusiasts who want to actually build an HUD. According to Mike, the system employs various optical paraphernalia, but at the heart of the mechanism is what lies closest to my own heart – a CRT Display!

Oscilloclock 3-inch X-Y-Z display, custom-built for an HUD

An Oscilloclock 3-inch X-Y-Z display unit, optimized for use in an HUD

Continue reading