Quake News!

Fake news – a common keyword these days. Fortunately, Oscilloclocks do not display fake news. But wouldn’t it be handy to see quake news on an exotic scope clock? This is the challenge [Atif] gave me – and one year and many grey hairs later, here is the result: The AfterShock Clock!

This custom-crafted Oscilloclock Core Duo assembly is a unique first in several ways:

  1. It’s the first scope clock ever that pulls in and displays real earthquake data!
  2. It’s the first scope clock ever that puts a dual-beam CRT to good use – one beam for the clock display, and the other for the earthquake and map overlay!

Earthquake display

The AfterShock Clock’s WiFi module connects at regular intervals to two public APIs (servers) to collect the latest earthquake events. It then feeds earthquakes to the clock’s quake gun controller, rotating quakes every 30 seconds. Cool!

(Note: flickering is due to camera effects and is not visible to the human eye)

Of course, there is the usual wide variety of standard clock screens to cycle through! The quake map’s beam is automatically dimmed for most of the screens, giving a soft ‘watermark’ effect.

Dual-beam CRT

The E10-12GH CRT used in this clock is certainly not mundane!

Beautiful spiral PDA lets you really see inside the cavity!

Nothing beats a dual-gun CRT for intricacy… (except a quad- or pentuple-gun CRT!)

Oscilloclock Core Duo

Atif wanted to create his own case, so he initially asked for an Oscilloclock Core. But currently a single Core set does not provide control, deflection, and blanking circuits to drive TWO electron guns… So he had two choices:

  1. Wait an eternity for me to redesign the boards to fully support dual beams.
  2. Get started now! Simply put two Core assemblies together, with some degree of inter-control and removing any redundant circuits.

Atif chose the latter – and the Oscilloclock Core Duo was born!

WiFi setup

Setting up the WiFi connection is easy – just connect a device to the clock’s administration SSID and pull up the admin page. (To foil any would-be hackers out there, the admin SSID is available only for the first 5 minutes after power is applied.)

Then, access the admin URL and configure the connection to your home router:

There are a million other advanced settings to tweak things such as quake polling interval, quake magnitude filters, maximum quake age before purge, and other geeky aspects….

Oh, I forgot to mention – the clock also synchronizes time against an NTP server, eliminating the need for a GPS module.

Like what you see?

Do you go for electron guns? idolize intricate electrode assemblies? Have a filament fetish? Or just want some quake news? This kind of clock might fit the bill. Let me know!

Bunker Club Clock


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!

Lissajous figures from 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:

Toshiba ST-1248D - Brass bezel

Kikusui 537

Metropolis Clock

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.)

Burn-in? Nope!

Many folks have asked whether screen burn-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

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.

My favourite screensaver – Flying Toasters!
(Image used under Fair Use terms)

While there is nothing as fancy as flying toasters, the Oscilloclock has several mechanisms in place.

  1. 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.

  2. 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!

  3. 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!

Timedrops in Spring

Spring… a beautiful time of year! I particularly enjoy the warm rains, with the soothing effects of raindrops pit-pattering into puddles outside my window.

But no longer do I need to look outside! Inspired by a recent post on Hackaday, a suggestion from [A-Nonamus] in the neonixie-l group, and by Spring itself, I can now enjoy Timedrops on my Oscilloclocks:

See this in HD, and find more exciting videos on my YouTube channel
Music credits: Space Bazooka by Kirkoid (c) 2013 Licensed under a Creative Commons Attribution (3.0) license. http://dig.ccmixter.org/files/Kirkoid/43005


The current Oscilloclock firmware is written entirely in PIC 18F Assembly. The Timedrops feature leverages a Sprite Engine module, first developed for Halloween Seasonal Treats and later utilized in the Santa’s sleigh feature.

A sprite engine

A sprite engine

To display Timedrops, the sprite engine is initialized with 10 sprites – 4 digits for hours and minutes, a colon, and 5 ellipses as ‘ripples’. The 5 characters are set at the top of the screen with a randomized negative velocity. When a character reaches the bottom boundary, the sprite engine’s default explode sequence is started, and the associated ripple sprite is made visible and set to expand. When the explosion sequence for a character sprite is complete, the sprite is reset at the top of the screen.

Looking for the source code? Sorry – refactoring is still under way, and the latest revision with the Timedrops feature will be uploaded in the near future.

Santa in your Clock!

The world-renowned Santa Claus. How does he get in your house to deliver presents? Does he go down the chimney (if you have one)? Does he shrink and squeeze under your door? Of course not! What silly ideas.

Santa simply converts himself into pure energy and beams in!! I’ve seen this glorious event myself, and now you can too – with the latest Seasonal Treats enhancement from Oscilloclock.com.

Beam me in, Santa!

Beam me in, Santa!

Not only can you watch Santa on his travels, but you can even control where he drops his presents! Can YOU help him deliver the gifts?

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Circle Graphics – Lissajous figures

By the time you read this post, you must have seen the term “Circle Graphics” in a thousand places across the site.

In fact, “Circle Graphics” is not an official term – I just use it to describe how shapes are drawn on these clocks:

Everything you see on this screen is made up of CIRCLES! Blank out part of a circle and you get an arc. Squish an arc and you get a line. This clock simply draws circles, lines, and arcs of different sizes at various points around the screen. It does it quickly. And it does it very, very well!

The effect of using circles is beautiful – shapes are smooth and precise, with no jagged edges or pixelation.

Beautiful circles with no jagged edges

Making “perfect” circles

I carry on as if it were some incredible new concept or discovery, like the Higgs boson. But in fact, the analog technique of constructing perfect circles, ovals, and lines on a CRT is very, very old. These figures are really part of a class of shapes called Lissajous Figures.

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Oscilloclock.com proudly presents a new feature – Seasonal Treats !

This month, the ghosts come out of the attic and merge with the electron stream, leaving their telltale prints in the phosphor… but if you get too scared? Just push the button and blow them up!

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