It’s the 1970’s. The cold war. The U.S. and Russia aim nuclear weapons at each other. How do you prepare for the worst? Why, you build a bunker, of course!
Today, [Ian] has done just that. Not a real nuclear fallout shelter, of course, but a period-themed bar called the Bunker Club. What better way to face disaster, than over drinks with the mates!
Ian decided to pepper his bar with vintage equipment that looked the part. But he wanted to make them truly functional, to entertain his retro-loving customers. So, he commissioned the Bunker Club VectorClock!
Now, regular followers of the blog will easily recognize the base unit here as a Tektronix 520A Vectorscope. So far a total of four of these delightfully-lighted machines have been converted to retro Oscilloclocks – see the Gallery for other examples.
But as always with any model, Ian wanted to make some cool customizations. Let’s look at two of them.
1. External XY Input
First introduced in the Metropolis Clock, this feature allows Ian to input two signals and visualize them in X-Y format on the screen. This is very, very useful for generating custom Lissajous figures externally – using either a cheap signal generator, or even an iPhone!
Cool Lissajous figures – even from a humble iPhone! (note, this picture is of the Metropolis Clock)
The external signals are rendered within a rectangular ‘window’, pre-configured to look nice alongside other standard parts of the Oscilloclock screens. For some screens, the window is drawn large but with a lower intensity, forming a kind of ‘watermark’. This is an awesome effect!
2. Custom Logos
Nearly all Oscilloclocks feature some kind of customized logo. Past examples include the customers’ business’ name, the name of the oscilloscope manufacturer, or even the name of the customer’s favourite film:
In Ian’s case, the obvious candidate was his new bar’s official logo – a very chunky-looking rocket blasting through the atmosphere!
Further enhancements … on the way
It seems Ian enjoyed his first clock so much, that he has commissioned a second, with a completely different physical look. Some further special effects and display animation are planned, to further enhance the nuclear theme and keep his customers happy. Stay tuned!
Like what you see?
Do you own a bar? Well, normally you wouldn’t want a clock in your premises, as it would help customers keep track of their time, which would be bad for business. But Oscilloclocks are so much more than timekeepers! Recent feature additions make them lots of fun to watch and fiddle with. If you have special ideas, let me know!
(Disclaimer: Oscilloclock.com hopes that no-one is offended by the deliberately light-hearted tone of this post, in referring to the decidedly serious topic of nuclear warfare.)
It’s been a long while since I wrote about the 3″ VGA Display assembly, which was used for an RWR indicator in a fighter cockpit simulator.
The customer came back and requested four more. But could I stack the boards to make the units more compact? Of course!!
This particular assembly is rather tall because the client requested an in-built mains supply board, sitting at the bottom. The normal configuration using an external power pack is half the height. (In which case it’s not quite a “cube”…)
With green filter and replica RWR escutcheon fabricated by the customer. How real is that!!
And if you aren’t into aircraft indicators, you could always have a bit of fun!
Is a VGA Cube right for you?
Maybe. Or maybe not! These units incorporate binary blanking – I.e. The beam is either on or off; no shades of grey. Hence any VGA image composed of thick line art like RWR will display well, but shaded or coloured displays such as an attitude / horizon indicator would not work so well.
Below is a Windows XP login screen… Not exactly a flattering image!!
VGA Board – better and better
The latest VGA Board rev 1.1x is small and cute, and is compatible with the standard Oscilloclock Deflection and Power Boards.
In keeping with tradition, the VGA Board employs entirely analogue techniques to generate the horizontal and vertical sweep, triggered by incoming sync pulses. A high-speed analogue comparator with adjustable levelling is used to convert analogue RGB into binary blanking. Naturally, inputs are ESD protected so you can’t easily blow the chips!
New VGA Board revision (left) – meaner and leaner!
Like what you see?
VGA Cubes are like any other Oscilloclock product – each unit is hand-crafted to order and fully tested so that I can optimise for the selected CRT and provide a decent satisfaction guarantee. To date I’ve made five – and always happy to discuss a sixth! If you have a passion for raster rendering, let me know!
Many folks have asked whether screenburn-in, or phosphor burn, is not a problem. They are concerned by what was a frequent occurrence in the CRT monitors and oscilloscopes of yesteryear: a permanent scar prominently visible on the screen…
Phosphor burn – this old spectrum analyser looks ‘on’ even when it’s off!
To understand why this occurs, first think of an iron burn. If you deliver too much heat for too long into the same spot, your nice new Oscilloclock brand T-shirt will feature a prominent (and permanent) mark as shown below.
Iron burn – this shirt’s fibres have been literally scorched!
(I could push for another analogy, and describe livestock branding – but I think you get the message.)
In a CRT, a beam of fast-moving electrons bombards the phosphor coating on the screen to produce an image. If the beam is too intense, or it is allowed to trace the same route on the screen over a long period of time, the phosphor compound may degrade and lose its luminance. The end result is:
The screen won’t light up well in those spots any longer.
The damaged areas may appear dark even with the power off – a ‘ghost image’.
Interestingly, this damage does not actually shorten the working life of the CRT! (It does not affect the longevity of the heater, or the amount of gas permeating the vacuum.) However, it is certainly not attractive, and is most definitely NOT an effect you wish to observe on your fancy custom-crafted Oscilloclock…
Keeping the ghosts at bay
Happily, screen burn-in is not much a problem with the Oscilloclock. Let’s see why.
1. CRT selection
Some CRT types and brands are more susceptible to screen burn-in than others. There are a number of factors for this, and all of these are considered during CRT selection to minimize the risk of burn-in:
First, there is the phosphor compound used. Some phosphors, just by their chemical makeup, degrade faster than others. More significant, though, is the fact that some phosphors require more energy (electron beam intensity) to produce the same level of visible light output as others.
For example, a long-persistence blue P7 phosphor, such as used in the Model 1-S and the Prototype, is by its nature ‘darker’; it requires a higher beam intensity than the crisp green P1 or P31 phosphors used in many other models. The higher beam does make the P7 more vulnerable to burn-in.
Different phosphors need different intensities to appear ‘bright’ – so some will burn faster
Fortunately, the simple protection mechanisms in place in the Oscilloclock (we’ll get to these later) will avoid burn-in even on sensitive phosphors. The customer need not be concerned about this risk factor, and can select any of the available phosphors.
The second factor is the thickness of the phosphor coating. The thicker the phosphor, the less burn-in for the same beam intensity. Some CRTs are infamous for having ridiculously thin phosphor coatings, making them extremely susceptible to burn-in. Sadly, some CRTs that are most readily available today fall into this category, and their data sheets even specify an incredibly short maximum longevity of 1000 hours. That’s less than 2 months of continuous use!
Beware CRTs with short lifetime ratings – they may have ridiculously thin phosphors!
Most CRT manufacturers did not publish lifetime ratings, nor did they publish specifications of phosphor thickness. In the Oscilloclock lab, I rely mainly on my and others’ experiences with the manufacturer, and pick and choose only the highest-quality CRTs. Expensive – but definitely worth it!
The third factor is the use of any additional technology in the CRT that would allow for reduced beam intensities. The most common example is the aluminized screen, an additional coating on the rear of the phosphor. This coating reflects the light that would normally emanate from the phosphor towards the rear of the CRT, back into the phosphor (and the front of the screen). A much more efficient use of energy!
However, this technology was a later development, so many CRTs with an aluminized screen tend to be rectangular and have an in-built graticule. These may not be as visually pleasing in a standard Oscilloclock as non-aluminized CRTs.
2. Software (Firmware) protection mechanisms
My favourite screensaver – Flying Toasters! (Image used under Fair Use terms)
Remember the phrase “screen saver”? In the pre-LCD monitor days, most computers employed some form of software that would stop the same image being displayed for too long, to avoid screen burn-in.
While there is nothing as fancy as flying toasters, the Oscilloclock has several mechanisms in place.
Hourly XY Bump screen saver This feature simply shifts the image by a small amount in the X and Y directions every hour. The shift pattern repeats every 31 hours (a prime number), to ensure that every hour numeral will be placed in every screen position.
Auto screen switch This feature simply cycles through the screens (clock faces) at regular intervals, configurable from 0 (off) to 90 seconds. This is by far the most commonly enabled feature, as it allows one to enjoy all the Oscilloclock screens without touching the control!
Auto power off Strongly recommended by Oscilloclock labs, this feature simply turns the Oscilloclock off after a period of non-activity (not touching the control), configurable from 0 (off) to 90 minutes.
This may sound counter-intuitive, but in practice, nearly all Oscilloclock owners are comfortable to turn their unit on just when they intend to enjoy it, and allow it to switch itself off. The exceptions are clocks that are permanent fixtures in offices and restaurants, in which case the owners manually turn their clocks on and off together with other appliances in the premises.
These features are of course highlighted in the Operation Guide that accompanies every Oscilloclock.
Summing it up
So there we have it – there’s not so much to be concerned about after all. While CRTs do have a delicate phosphor coating, by selecting a decent CRT in the first place and looking after it in use, the risk of screen burn-in is drastically reduced. In fact, in 7 years of constructing Oscilloclocks, as of today not a single unit has come back for a CRT replacement!
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:
And here is what [Mike] was able to with it, after implementing a totally fresh controller design incorporating Circle Graphics:
[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 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!
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!
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.
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 Kikusui Electronics Corp. logo
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).
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!
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
Finally, an Oscilloclock Supply Board was needed to power the other boards.
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:
Sweep adjust control in its original stateAfter removing the potentiometerThe encoder, after hacking with a hacksaw!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!
