Design of the Curta. 12 Days of Curtsmas 4

12 Days of Curtsmas Chapter 4: Design of the Curta
This is a Curta Type I, built in 1952. Stay tuned for episodes every other day, December 3 - 25. Thanks as always to the person who gave me the Curta.
Chapter 11 (December 23) will be a mailbag episode! So please ask questions, etc.
End song inspired by "Hotter than a Molotov" by The Coup. • The Coup: Hotter Than ...
Jingle bells sound from www.freesoundslibrary.com, CC-BY-4.0
Curta case photo by Wikimedia user Nol Aders, CC-BY-SA-3.0 commons.wikimedia.org/wiki/Fi...

[@johnsrabe]

This series is a lot better than I was expecting, and I had high hopes in the first place. I appreciate the amount of work you are putting into it. Thanks!

[@ryanatkinson2978]

I was over at a friend's house when I noticed a Curta sitting on his shelf, I about shat myself out of excitement. So damn cool

[@thinkbolt]

"I'll pretend I've already invented everything." Man! That's confidence!

[@pankoBreadCroisant]

those are some serious KNURLS

[@johnsrabe]

1:56 Wow. What a great way of stimulating your own creativity. Jump right over the mental roadblock of how, get to the what, and go back to how! This would work in any number of applications.

[@alanesq1]

I didn't mind that these are so stupidly expensive as they are just some novelty with no interest to me. Now I want one, so thanks for that ;-)

[@MattMcIrvin]

I'm getting this yearning for old-school calculating machines but I think slide rules might be much easier to collect--much cheaper, and more likely to be in working order after 60 or 70 years!

[@alanesq1]

@@MattMcIrvin Be very careful, I just happened to watch a video on TH-cam about a Friden machine and next thing I know I have 30+ adding machines - lol

[@MarkEichin]

I've always been fascinated at how most mechanical calculating devices have at most one spark of an idea and then years of refinement... where the Curta is just an Entirely Different Thing that didn't evolve from other devices, nor did anything really evolve *from* it. I'm glad you actually have one!

[@josephmarrow5598]

Recently watched your video on publishing a paper, really encouraging given how much time I've spent making no progress

[@jasonlee5477]

So cool, I would love to an Apple style product announcement featuring the Curta

[@ChrisStaecker]

Would've fit in perfectly next to Picasso in their old "think different" campaign

[@jogloran]

I know it’s a weird thing to compliment you for, but aside from the excellent content, your diction has me in stitches.

[@biquinary]

Knowing Prof. Staecker, there is likely a video planned for this, but just wanted to mention to the interested viewer that Curt Herzstark was prevented from freely working on the CURTA calculator because of the "difficult circumstances" in which he lived.
(I'm being deliberately vague here because Prof. Staecker never fails to deliver smart commentary, so I'd rather leave it in his capable hands. The wikipedia page for Herzstark has a summary you can check out in the meantime)

[@ChrisStaecker]

no spoilers!

[@pierQRzt180]

Yes, like an very sad anime plot. Where you get spared only to create a present for a guy with funny mustaches.

[@Nashvillain10SE]

SPOILER ALERT: There are 8 more episodes on the Curta!!!

[@RossMarsden]

It's official. I now want one of these. I will take steps to find one and buy it.

[@Bavergnag]

~ORIGINAL~

[@Glutnix]

Hard to believe we had to wait FOUR EPISODES to get an ~ORIGINAL~ from Chris

[@pierQRzt180]

those videos are too underrated. TH-cam should obscure all the other videos and show only yours for a couple of days to balance things.

[@LuisRodriguez-vh6fg]

I'll be home for Curtsmas 🎉

[@_skysick_]

Are we going to get a video about how the mechanism does carries?

[@_skysick_]

Is there just a tooth between the 9 and 0 on each digit? Or does the main drum somehow make separate carry teeth unnecessary?

[@ChrisStaecker]

@@_skysick_ It's a bit more complicated than just an extra tooth, because the subtraction mode needs to do carrys differently. Popping the doink shifts the drum so that it adds complementary digits, AND it also shifts the carry system to behave appropriately for subtraction instead of addition.
I don't have a video planned on this- to me it seemed more complicated than it was worth, and I just about hit my limit for doing animations, which is much harder for me than traditional filming.
All this is shown in the video "How the curta works" by @Mechanicalcomputing, around 4:20. He uses the original parts to show it, which is cool but sometimes makes it hard to follow.

[@_skysick_]

​@@ChrisStaeckerThanks I'll check it out. Hopefully it's clearer than the bizarre CGI animation I found about it!

[@MattMcIrvin]

Aha, that's how that +1 for complement subtraction works--the rightmost digit has an extra gear that engages the next digit's teeth in subtraction mode! (And there's a ten-tooth gear for subtracting 0, so the addition is at the opposite end of the drum from what I guessed earlier.)

[@lafcursiax]

5:18 Oh, those are flecks of rubber? I thought they were the ground pepper!

[@legofreak5769]

wow it really is smaller than i realized

[@MattMcIrvin]

Designing the product from the user interface in is something good teams do all the time, but it's easy for an engineer to think in the other direction and end up with something whose behavior is determined by its implementation and is not intuitive to the user. Some of the early calculators seem to be like that.

[@Lilac757]

For the algorithm.

[@MichaelGriffin_]

Every video I want one more and then I have to remind myself of the truth.

[@getjaketospace]

Curta

[@ColtonRMagby]

The mechanism inside the Curta is simple, yet effective.

[@StephenRansom47]

Boy, that Noodle was sure working for Curt. His dad must have been So Proud 🥹 “Just look at my boy go!” 🤔Jinkies maybe he’s going to surpass me … NA! He’s just a kid. *then Dad panics 😅
These videos are great, I remember seeing my first Curta online … and I was like, “It’s a mini Babbage Device!” 😳