Old devices refusing to be repurposed

(Originally posted on the RetroMat site in May 25, but sits better here). 

Buoyed by the successful rescue of an old Android phone (see below), I've just tried some other old devices that were lying in my electronic junk box, but unfortunately, for different reasons, I was unsuccessful:

•  Another Moto smart phone, different model, that simply fails to power on when connected to a power supply. Plug and phone get vaguely warm and when disconnected, there's a brief flash from the light at the front. Cause: battery failure.
•  An HTC Desire phone from around 2010. It starts promisingly: the battery gets charged, the phone powers up and displays a logo and vibrates and buzzes loudly, but the screen goes blank after a while. Sometimes it comes back on and the buzzing is repeated insistently, but it won't  go beyond that initial screen. Suspecting the removable battery could be at fault, I've checked it with a multimeter, but the voltage was pretty close to the specified value. I've been able to get to the Android menu by pressing and holding volume down and then the power button. I've then tried a few of the options there, such as erasing data, selecting the 'rescue' (reset?) option and even 'fastboot', whatever that is, but all to no avail. Back it goes into that box! Cause: hardware failure of some type.
• A Hipstreet W7 tablet. IIRC, this came free with a phone contract many years ago. No-one found it remotely useful at the time, so it was consigned to the box of unwanted devices soon after. Perhaps it could find some use at last as a media player? When plugged in, after some time, it starts up and displays a family member's name and a password prompt. There's a reset button, but all that does is restart the tablet, not reset it to factory settings. It seems, in order to rescue the device, it needs to be booted up with a previously-created rescue 'disc' in the usb port. Needless to say, there isn't one. Unfortunately, but not unsurprisingly, said family member doesn't recall the password after all this time. Cause: security policy.
• A 4 GB Sony Walkman (NWZ-A816) from around 2008. It was used often until I had my first smart phone a few years later. The battery had started to expand a while ago, so it was removed and disposed of at the recycling centre. It still powers up, though, if plugged into a power supply by USB cable. It can even be made to continue to function as a media player (music, photos, videos).  What it steadfastly refuses to do, however, is to reliably accept files that I try to transfer to it from my laptop - I keep getting message libmtp error: could not send object. IIRC, I had a similar message when trying to send files directly to the Moto G rather than to a MicroSD card mounted locally on my laptop. It's quite possible that the problem arises from the file transfer protocol as implemented in my laptop's OS (Linux Mint). However, given the limited usefulness of the device (small capacity, no battery, no support for flac files!), it's probably not worth pursuing further. Cause: incompatible standards?

Repurposing an old Android phone

(Originally posted on the RetroMat site in May 25, but sits better here).

For some time, I've been looking for a way to play my digital media through my Onkyo 'hifi' receiver from 2006 which has no USB port or SD card slot. I like the machine - it sounds great, is solidly-built and as well as a  CD player, has a radio, including MW, which I use for receiving distant stations. We have a Chromecast Audio that can be connected to it for on-line audio streaming. In all other respects, it meets requirements and I'm in no rush to replace it.

(I tried using an old QNAP NAS system, but it was a faff. IIRC, I was able to use it from our TV, using twonky, a now defunct standard, but would have had to move the receiver to the TV in order to connect the two and that wasn't convenient. Plus the TV won't play flac files. I think I tried using the NAS from my phone and casting from there, but couldn't find a way to stream from the NAS and instead had to download files. After that, I just gave up).

Years ago, when I had an Android phone with external storage, I'd connect the phone directly to one of the inputs. Since then, I've had hand-me-down iPhones and can't do that and my digital media has been restricted to my laptop.

There are impressive looking machines from Brennan. In time, I'd like to rip (losslessly) my entire CD collection, so one of these could make sense. However, they are bulky and somewhat over-specced for my needs: first I already have a CD player in the Onkyo, second I can rip CDs on a PC, and third, I don't really require all the high-tech connectivity they provide.

I could use a modern mp3-type player, but don't want or need a high-end device from the likes of Astell & Kern, or FiiO. Sony Walkman's are within my budget, but you have to pay up considerably if you want a decent amount of (non-expandable) internal storage. Plus, as with smart phones, such devices seem to be intended to be disposable, having batteries that may not be easy to replace.

For now, I've decided to re-use an old Android Moto smart phone with a MicroSD slot, with support for up to 512 GB of storage. I wasn't overly-optimistic at first that this would work after so many years. In fact, two other candidate phones couldn't be started. However, as I began to charge this one, it started OK and the battery seems OK. I've removed or disabled as many apps as I can, disabled wi-fi and bluetooth and as there's no  sensitive information any more, I've removed the screen lock, leaving what is in effect just an mp3 player. The google search prompt won't budge, but it's not a big deal. For now, it has just a 4 GB card in it and it's being used to play a mix of mp3, wav and flac format files. I'm planning to replace the card with a much larger one - how well it scales up in practice, we shall see.

Two-colour movies revisited

Updated 17 Feb 26

A short movie from 1930, The Devil's Cabaret, popped up in my YT feed recently. It's an early MGM talkie filmed in two-colour Technicolor. It's pre-code, well worth watching in its own right. Colour and sound are actually quite good. Anyway, it's prompted me to take another look at my earlier post on the Friese-Greene process, also in two colours.

Two things stand out:

First, each film frame in the former process is in 'full' colour, whereas each frame in the latter process is in a single colour, complementary to that of its neighbours and relies upon persistence of vision to achieve an impression only of colour, making it more of a curiosity, as it can't have been easy to watch at the time. (Luckily for us, the modern F-G digital print doesn't do this).

Second, was I really correct in saying that the camera used in the latter process had a red filter alternating with no filter at all? I made that statement having recently seen the TV programme, but now all I can see online is that Claude F-G used the same process (Biocolour) that his father had invented, with a camera using red and green filters alternately. I would have thought that two filters would have made it easier to provide good colour reproduction in the final print, as well as better mechanical balance for the camera. I'll just have to see if I can find The Lost World of Friese-Greene documentary...

Core memory plane - please help identify!

Following on from the project mentioned below, which uses two transistors and four resistors to store one bit of data, I remembered I have a core memory module where just one ferrite ring does the same job. (Clearly, transistors had to shrink in size a fair bit before core memory like this could be replaced). And data is retained if power is lost! I bought it some years ago on eBay and was told at the time that it came from a computer at a ground station that was part of the network used to track Apollo missions. Unfortunately, I have no more details and have been unable so far to identify it, so please let me know in the comments section below if you recognize it!

It contains 48x64, i.e. 3072, ferrite rings for storing 3k bits of data. On one face, the sides are numbered 1 to 4 in ink and there is some text, also in ink: 363-105, an identifier perhaps. One of the corner holes is highlighted in yellow (paper triangle on one face, paint on the other), presumably to indicate the correct orientation for mounting it in a stack of identical modules. It looks like it was made in a workshop rather than a factory, suggesting it could have been a prototype or from a small production run.

A vintage binary electronic adder & counter project

Originally posted on the RetroMat website, but fits better here.

Also replaces an earlier blog posting, but keeps the time-stamp.

I may at some point try to re-create either the BEATLE machine or the one described in the book. In the meantime, I've started a page on the RetroMat website with some simple circuits based on the literature.

=====

Or A Binary Electronic Adder with Transistorized Logical Elements (BEATLE).

This is prompted by memories I have of a project that I and other pupils contributed to at Wellsway School around 1973/4. It was led by our Maths teacher Mr. Grace. Before I started to investigate, as far as I could recall:

• the machine had a binary counter with lights, could possibly perform simple binary arithmetic and could be used to test logical propositions
• it was based on one described in a magazine article from a few years before, referring to it by the acronym BEATLE (well done to whoever was responsible for that!)
• it made extensive use of flip-flops for memory. This was the first time I had come across the term and I remember soldering one or two of these
• the counter could be driven by a high frequency signal and hence act as a clock or timer, the first light in the chain seemingly permanently on, with the next one flickering rapidly and the ones after that flashing ever more slowly, at half the rate each time.

After some research, I found mention of the machine (indeed called BEATLE!) in a book, Teaching School Mathematics, edited by W. Servais and T. Varga, published in 1971 by Penguin Books & Unesco. In turn, the book refers to two articles by A. Wilkinson, a teacher, in the journal Mathematics Teaching, published by the Association of Teachers of Mathematics:

• MT 31, Summer 1965: A Small Computer Demonstration Model (i.e. the BEATLE)
• MT 32, Autumn 1965: A Computer Logic Demonstration Board

In addition, in the first article the author refers to another article in the previous journal:

MT 30, Spring 1965: A System of Logic to Aid in Teaching Mathematics, by G.J. Flanagan & L.Molyneux of the University of Newcastle-upon-Tyne.

These journals are available online, but are behind a paywall.

At the core of the BEATLE is a toggle flip-flop, that is used as a divide-by-two circuit and is referred to as a scale-of-two. It is built using NOR gates. 

The machine comprises the following main units:

• a Binary Arithmetic Unit: a binary counter with 9 scale-of-two units to accumulate and display sums (up to 511) of the numbers input
• a store: a binary counter with 5 scale-of-two units which stores the twos complement of the number to be added
• a pulse clock to increment the contents of the BAU and store 
• a control panel to allow decimal numbers in the range 1 to 9 to be input via switches or a rotary dial, and with a button to start the addition of the input number selected
• a so-called routing network: twos complement wiring between the switches/rotary dial to the elements of the store.

The mechanism to add the contents of the store to the BAU is interesting, if limited:

• a decimal number, n, 1 to 9, is entered by the user
• 32 - n is put into the store
• an Add button starts the addition by means of an electronic switch, an AND gate, with input from the Add button and pulse clock
• for each pulse of the clock, the contents of the BAU and store are incremented by 1
• after n pulses of the clock, the content of the BAU has increased by n and that of the store has become 0
• when the store contains 0, the electronic switch is set to OFF and the pulses from the clock no longer get through to the store and BAU.

The computer logic demonstration board is a set of NOR gates that can be wired together to form logical circuits such as half or full adders. It can also be used to model logical puzzles and, when connected to the BEATLE machine, to solve them. When a solution is found, the appropriate lights are lit and the machine stops - reminiscent then of the code-solving machines at Bletchley Park during the war!

Comments:

• although referred to as a computer demonstration model, I don't think it merits that description: while the functions can be enhanced through wiring of new logical elements, it cannot be programmed
• using this method of addition, the input number range could be extended up to 16 without increasing the size of the store
• although not mentioned in the article, the machine could be modified to subtract numbers as well: a subtract button could allow the input number n to be stored directly, using a different routing network, but some extra logic would be needed to handle the unwanted digit arising from using this method. 
• the decimal number input method cannot be scaled up easily to large numbers, so is clearly limited in practice. Perhaps it should be replaced by binary input only and the twos complement obtained by extra logic to invert the number (easily done with NOR gates) and then to add one (but how?)?

I have also found the following relevant publications:

• Electronic Engineering magazine, July 1964: A Low Speed Single Supply Logic System, also by G.J. Flanagan & L.Molyneux. Useful background to the NOR gate implementation. Can be downloaded for free from here.
• Computer Models, also by Wilkinson, published in 1968 by Edward Arnold (Publishers) Ltd. Describes a later machine which performs addition and subtraction using half and full adders and shift registers. The author also shows how it can be enhanced to multiply two numbers, or to compare them. Can be downloaded for free from here.

Start and end of the seasons

Updated 6 Feb 26

Some musings originally posted on the RetroMat site in October last year

As we approach Halloween, I am reminded again of the wisdom of the ancients here-abouts who deemed this time of year as being (approximately) when Autumn ends and Winter starts.

Considering the hours of daylight, it makes so much more sense to have Winter starting at this mid-point (more accurately in early November, closer to Bonfire Night* here in the UK) between the Autumn equinox and Winter solstice, rather than as we do now, at the Winter solstice itself, especially as the latter is also known as Midwinter's Day.

(*Celebrating the foiling of the Gunpowder Plot of 1605, but no doubt replacing an earlier seasonal festival).

Similarly, for Summer, which should begin in early May, rather than at the Summer solstice, also known as Midsummer's Day. By the same logic Spring should start in early February, at the mid-point between the Winter solstice and Spring equinox and Autumn should begin in early August, at the mid-point between the Summer solstice and Autumn equinox. This still means there are four seasons of around 13 weeks' duration each, but they are now centred on the solstices and equinoxes.

In ancient times, these mid-points would have been noted or celebrated. Not surprisingly, the Church would have asserted itself by replacing or attempting to replace these festivals or occasions.

We have:

• end of Winter/start of Spring - Gaelic: Imbolc, Church: Candlemas, Catholic Church (Ireland): Saint Brigid's* Day
• end of Spring/start of Summer -  English: May Day, Welsh: Calan Mai, Gaelic: Beltane, Catholic Church associates the month of May with the Virgin Mary
• end of Summer/start of Autumn - Gaelic: Lughnasadh, Church: Lammas or Loaf Mass Day
• end of Autumn/start of Winter - English: precursor to Bonfire Night/Halloween**, Welsh: Calan Gaeaf (first day of Winter), Gaelic: Samhain, Church: Allhallowtide, comprising All Hallows' Eve, All Hallows' Day/All Saints' Day & All Souls' Day

(* quite distinct of course from the pre-Christian Irish goddess of the same name!

** meaning the 'pagan' celebration rather than the Christian All Hallows' Eve, after which it is named).

Note, in Welsh, the month of June is Mehefin, i.e. mid Summer, and July is Gorffennaf, i.e. end of Summer. The month of May is Mai, whereas we might have expected the equivalent of start of Summer. October is Hydref, the same as the Welsh for Autumn, although for consistency we might have expected it to be the equivalent of end of Autumn instead. 

Manned mission around the moon - 1955 style

This popped into my YT feed a little while ago. It's from 1955 and in part describes a very futuristic manned mission around the moon, a mere 13 years before Apollo 8 did just that, yet the two missions couldn't be more different in concept.

The following day, I learned that Artemis II could repeat that mission as early as February next year (2026), although unlike Apollo 8 and like the fictional mission, it will go around the moon rather than orbit it.

Telstar in 1915?

Wow - first, a depiction of a spaceship of the future on a cover of The Electrical Experimenter magazine from 1915 and second, communications satellite Telstar 1 from nearly fifty years later!

Friese-Greene colour process

One of the first posts I made on the RetroMat website around 20 years ago. It fits better here now and is a suitable first proper post for this blog.

Colour films using a single filter and no specialist projection equipment...

This was an attempt to simulate the two-colour photographic process used by Friese-Greene for cinema film, shown in Dan Cruickshank's 2006 BBC TV Series The Lost World of Friese-Greene. I was intrigued by this series, because of its promise of colour cinematography from an era usually associated with black and white images. His system was quite ingenious, amazingly using just one coloured filter in recording - the camera captures alternate images through a red filter on black and white film. These images are tinted red on the print of the film. The other images are unfiltered and then tinted blue-green (cyan), to complement the red. When the projected film is viewed, the brain sees a colour image, presumably through the 'persistence of vision' effect. This process requires no specialist projection equipment and is capable of producing realistic reds and whites, which must have been quite novel for the time. The drawbacks include flickering images, unrealistic blues and greens, coloured fringes for moving objects and the need to film in bright light.

First I took a colour picture, of my son,  chosen for his red rugby shirt, blue trousers and green background. (Although he was delighted to be wearing the Wales 'Grand Slam' shirt, he wasn't too thrilled about having his picture taken).

Using photo editing software, I converted it to a black and white picture, filtered in red, to simulate a picture taken in black and white through a red filter. This is the first photo taken with my virtual F-G camera!

Then I tinted it red to produce the first image in the finished film.

Next, I converted the original picture to black and white, but this time with no filtering. This is the second virtual F-G photo.

Then I tinted it blue-green (cyan), to produce the second image in the finished film.

I then merged the red and cyan images together to produce a two-colour picture.

The  reds are faded, because red light in the original also contributes to cyan in the final image. Also, skin tones look slightly green. Increasing red saturation reduces these problems, but does reduce the colour of the grass, as shown below. There is no discernible blue at all in either image.

If a scene contained a large expanse of blue, for example a cloudless sky, then it should be possible to reproduce this more accurately, by replacing the cyan colouring on the developed film with a colour having a higher blue content. Similarly, for large expanses of green (fields or trees), a colour with a higher green content could be used. I wouldn't be surprised if this method was used by Friese-Green, because the blues and greens are quite convincing in such footage of his that I've seen. I tried this here, tinting the unfiltered black and white image picture green, not cyan. The grass looks more realistic, but the green cast to the skin is more pronounced.

Alternative ways of combining the red and cyan images:

• Simulate the projection method used by Friese-Green. To do this, I used Windows Movie Maker to create a clip. The minimum duration was 1/8 second. I played it back with Windows Media Player using fast forward and repeat. There was too much flicker for prolonged viewing, but there was an indication of colour. 
• View cyan and red images side-by-side as you can for stereo images. This doesn't work at all! It just results in a black and white image! So, this method could not be used to produce stereoscopic colour slides. This shouldn't have surprised me, because when you see 3D images using red and green glasses, the image always appears black and white.

So, this is an interesting process. Using just one filter on the camera can give quite convincing results, especially with some forethought in setting up the 'shoot' and in preparing the film afterwards. It was of course, a technological dead-end. Once the hurdle of creating a usable and affordable 3-colour process had been cleared, then this system and others like it would have become redundant.

After a hiatus...

Now picking up this blog again after nearly 20 years!

I created this blog in 2007, posted a couple of items and promptly forgot all about it!

Now, I see a use for it, as a way to complement my RetroMat website with smaller posts, to promote that website and to get feedback.

Constructive comments welcome - either against a relevant post, or below, as appropriate.