VirtualColossus

It's time to fill out some of the metalwork that holds everything together. It's no wonder the SG-41 weighed in at around 13kg especially as Germany were running out of lighter metals by the end of the war.
@cryptomuseum.bsky.social @threejs.org @tnmoc.bsky.social

One of the final external controls completed, the F/L knob. This switches the SG-41 between Funktion (Operate) and Löschen (Clear). Clear mode releases the mechanism from the cipher wheels so they can be moved to a new position or reset. @tnmoc.bsky.social @threejs.org @cryptomuseum.bsky.social

Last month, I was thrilled to be invited to GCHQ in Cheltenham to see their rare SG-41 cipher machine for real!
It has answered many questions about this amazing WW2 machine. I can now move on & complete my latest sim which will be released (hopefully later this yr) on my site virtualcolossus.co.uk

That is SO cute! Look, it's a little knitted Colossus
I WANT ONE!

A new and very informative posting by the Sigint Historian, which sets Sigint history in perspective and generally offers reflections for historians.

siginthistorian.blogspot.com/2025/08/reco...

I've been continuing work on the paper feed mechanism after a very exciting visit which has helped a huge amount (more on that soon). The paper feed lever allows you to extract your printed cipher/plain text from the SG-41. @tnmoc.bsky.social @cryptomuseum.bsky.social

Yesterday we unveiled a new mural honouring Tommy Flowers, He was the brilliant engineer behind the Colossus computer. A truly fitting tribute to his genius and legacy.Thanks
@HeritageFundUK
& @TommyFlowersFdn
#TommyFlowers #Colossus #VJDay #DigitalLegacy Photo credit: Andy Taylor & Dave Wild

The Kryptos Key Is Going Up for Sale Jim Sanborn is auctioning off the elusive solution to K4, the outdoor sculpture that sits at CIA headquarters.

Jim Sanborn is to auction off the solution to K4 of the Kryptos Key, the outdoor sculpture that sits at CIA headquarters.
Would you keep this to yourself and guard the secret to allow the game to continue or release for the world to know the answer?
www.wired.com/story/jim-sa...

Preserving the legacy of Tommy Flowers: uncovering lost histories Join us to honor the GPO engineers who worked on Colossus, as we showcase the Tommy Flower Mural

Celebrate the legacy of Tommy Flowers! Join us at The National Museum of Computing on Friday, 15th August to unveil the new Flowers Mural.
Secure your place here: bit.ly/4ljjOuJ
@fitzroviaNoir @tommy_flowers_aberfeldy #TommyFlowers #Colossus #TNMOC #ComputingHistory

As well as working on modelling & animating the complex paper feed mechanism, I've been having a play adding a few extra visuals. Some useful (hiding specific parts of the mechanism to see how it works) and some just eye candy!

@tnmoc.bsky.social @threejs.org @cryptomuseum.bsky.social

Just when I thought I'd got past the most complex bits for Virtual SG-41, I find the paper feed mechanism. It's buried in deep on the left-hand side and includes a cam, 3 levers & 2 ratchet/pawls all which need to be modelled & animated! @tnmoc.bsky.social @cryptomuseum.bsky.social

I've added the letter counter to the SG-41 this week so take a look at how that works. Also, I've animated the folding handle so the machine can be packed away for travelling.
@tnmoc.bsky.social

What an incredible visit to The National Museum of Computing (@tnmoc.bsky.social) yesterday!

Seriously, it's one of the most brilliant museums I've ever had the pleasure of exploring

It’s not just about seeing how tech progressed; the passionate staff weave incredible stories around the exhibits
🤩

I broke more than fixed this week! I'd placed a few items in the machine out of line so last few bits didn't fit. I re-checked the scan so all fixed now!
The question to answer today - "What happens if you run out of paper?"
@bletchleypark.bsky.social
@tnmoc.bsky.social
@cryptomuseum.bsky.social

Dons pay tribute to Bletchley Park Codebreakers with new away shirt The new shirt pays homage to the Enigma Codebreakers of Bletchley

MK Dons pay tribute to Bletchley Park Codebreakers with new away shirt! It features Enigma key tops on the fabric as a tribute to the Bletchley Park codebreakers. www.miltonkeynes.co.uk/sport/footba...

Lots to show you today for Virtual Schlüsselgerät 41. Working out the print mechanism meant going back to uncover the cage drive works in detail! New drive mechanism, the print wheels working and switching between encipher/decipher. Phew! @tnmoc.bsky.social

OTD: 23rd June 1912, Alan Turing was born. Best known for his work on Enigma & the Bombe, he also wrote a paper in 1936 "On Computable Numbers" outlining a computing machine. After WW2, he designed one of the first computers, the ACE - run it for yourself; pilotace.virtualcolossus.co.uk

Today marked a fantastic opening performance of ‪‬ "Hush Hush! A Bletchley Story" it's everything we hoped for and more. This amazing group captivated audiences with their unique take on the Bletchley Park story. So much positive feedback! Don't miss your chance to see it @mikrontheatre.bsky.social

Time to start on the next part of Virtual Schlüsselgerät 41. Now we have the actual PRNG (pseudo-random number generator) working, the next part is to print! Unlike the M-209, the SG-41 has 2 tapes; one plaintext & one encrypted. Wish me luck!
@tnmoc.bsky.social @cryptomuseum.bsky.social

Can I maybe ask a favour?
This Friday, I'm walking in the Milton Keynes "Midnight Moo" to help raise for Willen Hospice who provide free care & support for local people with a life-limiting illness. Even a small amount (if you can) would be amazing!
donate.willen-hospice.org.uk/pf/martin-gi...

Adding in a few shadows make all the difference to a simulation. This is made very easy with Three.js which is the JavaScript library I'm using for 3D.
The encrypted output is not from a coded sim, it's from the mechanics alone!
@tnmoc.bsky.social @threejs.org

Lincoln City's new shirt honours mathematician George Boole Binary code spelling out We Are Imps celebrates the importance of mathematician George Boole's work.

Lincoln City's new football kit features a coded message to celebrate George Boole who invented Boolean logic & was born in the city. The binary code spells out "We Are Imps"

www.bbc.co.uk/news/article...

Massive thanks to our phenomenal team! 🙌 They've worked tirelessly and are now completely set up for the Econet LAN Party 2025. Get ready for an incredible weekend of connecting, sharing, and creating 2025's biggest Econet network!
#EconetLANParty #AcornComputers #RetroComputing #LANParty

Now we finally get to see how all the messing about in Virtual SG-41 with cogs & cams starts to encipher our letter. A lot of work done in past couple of weeks to get here, this is a fiendishly clever device!
@tnmoc.bsky.social @threejs.org @cryptomuseum.bsky.social

Our Virtual Schlüsselgerät 41 was looking a little naked, so this week, I've been modelling it something to cover it up.
This really adds so much to the look of the machine, looking awesome.
Still lots to do, so keep following along.
@tnmoc.bsky.social

Now we've got the Pilot ACE completed, it's time to get back to our build of the SG-41 (Schlüsselgerät 41). Here's a very brief recap of where we'd got to and a quick additional set of levers hidden away behind the rotors to work out. @tnmoc.bsky.social @cryptomuseum.bsky.social

Thanks to ITV Anglia News for this awesome interview which was on TV this evening! Taken on site at The National Museum of Computing @tnmoc.bsky.social, it was exciting to talk about the Pilot ACE, Alan Turing & his work & to show off some of mine!
pilotace.virtualcolossus.co.uk

3D c/o @threejs.org

Setting up Pilot ACE right in front of EDSAC, they are old friends these two! EDSAC was working the year before ACE but both used mercury delay line technology. Many thanks to @tnmoc.bsky.social for helping me get setup for todays demonstration.

Just arriving at Block H, TNMOC for interview about my latest simulation, Alan Turing's Pilot ACE computer! @tnmoc.bsky.social

Today, we're highlighting Dina St Johnston, a pioneering woman in #Computing whose company, VPS, once owned our Elliott 803!

Learn more about Dina from Simon Lavington, TNMOC's Honorary Fellow from 2024 👉 buff.ly/kkHEChO

#RetroComputing #Museum #RetroTech