Unknown Domain

sjculley virtual display

Although most displays that are rendered graphics are good for effects but useless for reference this one actually helped me to realise that I could use a timing belt to transfer to power from the back of the unit to the main sprocket wheel...

MrMagic74 DIY

This is a more basic but equally interesting because of the encoder system used which a later video at the end of this post shows was used in some installations of these displays, unlike Jave.de's which used opto encoders to detect how many flaps passed based on a known starting point...

Real unit taken out of action:

Jave.de DIY controller

Early in 2011 a project went around the internets which showed a set of eight rescued split-flap displays which had been hacked to work again using an PIC microprocessor. I although he had some small photos on his blog here:


I decided to get in touch and ask for more which Markus kindly obliged despite his busyness, what I did manage to find out was that they were 52 character units, which is quite highly populated and like I thought the letters were probably screen printed (painted) on to the flaps. He also sent loads of great images which I hope he won't mind me reposting here for this resource...

Cowzaki DIY Display

YouTube user cowzaki has posted a few videos of a display his built which works fairly well although it's limited to showing one word, and cannot switch the characters separately. Also there is an amount of roll back on both unit, the display works nicely though.

This is his first version:

More recent second version:

I haven't seen a good explanation as to why he was working on this other than some kind of project called "Destination Imagination" in 2011 presumably at MIT by the video.

Split-flap Research Dump

In the next few posts I am going to dump all the research I have done on split-flap displays over the past few years that I can still find, this is videos, diy projects, and more stuff on split flap displays.

I am back on the war path again, this summer I am making serious moves to building one, and getting funding for a 140 character twitter version. I need to make a prototype first so I have been looking initially at materials to use for the flaps as the previous two versions have been constructed using polypropylene sheets supplied by Sea Whites of Bristol which have a mixed texture which is not ideal.

Visit to Charring Cross

After the advice I got the other day from a guy at Waterloo I decided to take a detour to Charring Cross station on my way home from work, it proved to be a bit late to get anything from them but contrary to what they said at Waterloo there are no Solari displays stored at the station to his knowledge, he gave me the card of the Duty Station Manager who I have emailed but he will be away until the end of this project, but for my own personal interest I wanted to get in contact with him so I am currently waiting for his reply.

Visit to Waterloo

Today after the site visit for the GDNM end of year show I went via Waterloo to get home, rather than just sit for 30 minutes doing nothing, I went and found a member of staff who directed my question the the Station Reception where a helpful member of staff informed me that the Solari displays which were taken down were disposed of as he was working when they were sitting in the skip outside the station. He did recall some members of staff taking their home station's flap with them but nothing was kept due to space constraints.

The time was not of waste as he suggested that I go to Charring Cross and ask there as they keep stuff like that in a mini museum of stuff they have, so when I am next in London I will check that out.

Finalised character set for Twitter….

I am off to Farnham tomorrow to use the laser cutter, and with any luck will have my mechanical parts, the parts which should assemble into a 52 character set of letters...

ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 £?!@/:.,#$()'" (the final character will be a special one, either blank or a white card).


Today I got a reply from the National Rail staff I have been talking to.


Firstly, sorry it has taken a few days to respond.

Trying to answer each of you points.

The split-flap indicators where widely used for customer information systems on the railway, but the final installations have now gone on National Rail – the last I was aware of was the large main departure board at Liverpool Street and some small displays in the ticket office at Lewis; I forget the exact date, but I think Liverpool Street has been replaced by LED panels for over a year now.  I know for sure that there are none left in service as the Network Rail maintenance standard to maintain them has now been withdrawn – the standard no longer has any use.

The majority of the flap indicators where supplied by an Italian company, Solari SPA and as such these indicators were often called ‘Solaris’ by railwaymen in much the same way as vacuum cleaners are called ‘Hoovers’ whomever the manufacturer is.  However, some flaps indicators were also supplied from a company, I think German, called Krone.

The newest indicators consisted of a number of modules, each module having 80 flaps – each module therefore being able to display 80 different sets of information, though inevitably there would be at least one blank in that set of 80.  Earlier modules had just 40 flaps.  The flaps were printed both sides with sets of information – this varied from a set of a group of stations split over the two flap sides to final destination split over two flap sides – i.e. the two together would show “Victoria” or similar.  The flap spindle was driven by stepper motors with electrical contacts or I think in some cases optical sensors being used to ascertain the position of the spindle and hence stop the motor once the module was displaying the correct thing.  One of the major disadvantages of flap displays was that every time the timetable changed altering train service calling points or final destinations changed or even for a train company name/branding change, new flaps had to be silk-screen printed and then inserted into the indicators ideally the night of the timetable change.  The new main departure boards such as those at Liverpool Street, Victoria and Charing Cross had the columns of flap modules pivoted top and bottom, so to change the flaps it was possible to turn the column through 180 degrees and change the flaps from the inside.  With older displays a tower or ladder was required to work from the outside.      The displays were built up of a number of modules, from typically just two for a single-sided platform next train indicator to many rows and columns of modules for a large departure board at major terminal station.  We never used flaps where one module was used for individual letters – hence this problem with having to change the flaps when the stations changed would not exist, albeit with the drawback of a far more complex and expensive display required, but airports did (and may even still do somewhere) have displays formed in this way.

One of the great advantages of flap indicators, which other alternatives have not fully addressed, though they are now getting close, is their readability under all lighting conditions and viewing angles.  There disadvantages was the need to change flaps, as above and the ongoing maintenance cost for something which is electro-mechanical.

As unfortunately the last indicators were removed over a year ago, I think there is little chance of getting hold of a module for you, they would have gone for scrap I am afraid.  However, as it happens, I do have a flap module at home (recovered from East Croydon ticket office in the early 1990s).  Whilst it was rather fragile and difficult to transport, I can take photos of it for you if that is any use?

Hope that’s of some help,

Please send me an email if you would like any further clarity/more information or photos of the module.



Tom Chaffin, Principal Engineer, Telecoms (Acting)

Thameslink Programme

<Address Removed>

Tel: <Telephone Number Removed>

Mobile: <Telephone Number Removed>

Flipping in 3D

This is a mockup of the split-flip displays I am trying to create in Flash for my FMP.

So far I have managed to work out how to make Flash CS4 / Flash Player 10 perform 3D rotation around a point so that the flipping looks real, next I am going to create a film strip like this running from A-Z, 0-9 and ? @ £ $ ! , . / : " ' ( ) punctuation marks.