13 videos · 3 hr 53 minBrass Brains: Computing With Gears
Hacker News keeps returning to one idea: a computer does not need electricity. This playlist starts with the smallest building block, a differential gear that adds two rotations, then shows those parts combined into Navy fire-control computers. From there it goes back through Antikythera, Babbage and Kelvin's tide machines, out to mechanical oddities, and ends with the case that analog computing may come back for AI.
Play all on YouTube- 19:31
Around The Corner - How Differential Steering Works (1937)
US Auto Industry · Picked by 17 · 2013–2024Start with the 1937 GM film HN calls a marvel of teaching: the differential it explains is the adding unit every later machine here relies on.
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Mechanical Computer (All Parts) - Basic Mechanisms In Fire Control Computers
Excelsior10000 · Picked by 13 · 2014–2025The 1953 Navy training film, the full-length upload HN prefers, shows how shafts, cams and differentials put together solve firing equations; several commenters admit rewatching it many times.
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The Most Powerful Computers You've Never Heard Of
Veritasium · Picked by 6 · 2021–2025Once the parts make sense, Veritasium supplies the history, from Antikythera to Kelvin's tide-predicting machines.
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Building The World's First Computer - Greeks, Clocks and Rockets - Antikythera Mechanism Episode 1
Clickspring · Picked by 7 · 2018–2024Clickspring's opening episode on rebuilding the oldest known gear computer by hand, using only methods the Greeks could plausibly have had.
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1:01:04Charles Babbage and Difference Enginge No. 2 | Doron Swade | Talks at Google
Talks at Google · Picked by 1 · 2012–2022Doron Swade, who led the team that finally built Difference Engine No. 2, tells the Babbage story; HN points to the section around minute 36 on Ada Lovelace.
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3:39(1/4) Intro/History: Introducing a 100-year-old mechanical computer
engineerguy · Picked by 6 · 2015–2023Bill Hammack's short series on Michelson's harmonic analyzer, which does Fourier analysis with springs and levers, is what HN links whenever Fourier series come up.
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3:05IBM Selectric Typewriter & its digital to analogue converter
engineerguy · Picked by 4 · 2016–2025Three minutes of slow motion showing an office typewriter with a fully mechanical digital-to-analog converter inside.
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8:36The 3D-Printed Curta Calculator
Adam Savage’s Tested · Picked by 2 · 2017–2025The pocket-sized Curta, here as a scaled-up 3D-printed replica, so you can see the stepped drum that the original hides.
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28:52EEVblog #854 - B52 Bomber Automatic Astro Compass Teardown
EEVblog · Picked by 2 · 2016–2017A teardown of a working Cold War navigation computer, for anyone who wants to see the cams and gears from the Navy film in real hardware.
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4:37Making Money Flow: The MONIAC
Reserve Bank of New Zealand · Picked by 1 · 2020–2022A change of medium: Bill Phillips' machine models a national economy with water flowing through tanks and valves.
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3:34Marble adding machine
MatthiasWandel · Picked by 0 · 2013–2021Matthias Wandel's wooden binary adder moves from analog to digital logic, and HN says it inspired at least one commercial marble computer.
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19:22Mechanical circuits: electronics without electricity
Steve Mould · Picked by 1 · 2022–2024Steve Mould turns the analogy around and builds resistors, capacitors and transistors from chains and sprockets.
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21:42Future Computers Will Be Radically Different (Analog Computing)
Veritasium · Picked by 7 · 2022–2025It ends where HN threads usually end up, with the argument that continuous computation could return for neural-network inference.