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Comment by hughrr | Hacker News Reader

Even more impressive is the analogue version without any ICs!

https://www.eevblog.com/forum/projects/oscilloscope-pong-for...

In the 70's and early 80's you could buy handheld pong game machines that were actually mechanical. The cases were all jazzed up to look like they were electronic, and some even moved a tiny lightbulb around the "screen," but they were all gears and string inside.

Blip, made by Tomy.

https://en.wikipedia.org/wiki/Blip_(console)

What's impressive is the build; even using exactly the same circuit, I would have gone the reliable (ultimately) time-saving route of schematic -> PCB.

If you’re building one then it’s not time saving. I prototype stuff like that is built today and most of the time it stays like it.

Also it doesn’t always work the same when you get it on a PCB

That is very beautiful :)

That's really cool but I think you should understand that it's not 'analogue' if it has a bunch of transistors. This is called discrete because each component does a single operation. I see from the schematics that he builds flip flops from transistors for example.

Um, err, I’m an ex EE. Everything is analogue underneath, even digital. It’s all just shuffling electrons around.

The whole device there is made from discrete opamps. Sure there are some flip flops in there but they are analogue too! (Build one and poke it with a scope and look at the rise and fall times for the collectors)

A quick scan of the schematic and I'm not seeing flip-flops in there. There are analog muxes with the fets, but maybe I missed something?

The function generator page has a flip flop labelled. The multiplexor logic has several unlabelled examples I think.

In that case let's get rid of the term 'digital' then, since analogue must clearly and fully describe all the phenomenon.

> understand that it's not 'analogue' if it has a bunch of transistors.

That's ... not how it works. It's pretty much an analogue computer hardwired to play pong.

Discrete means "separate", "single", "stand-alone" in this context (https://www.sciencedirect.com/topics/engineering/discrete-co...), in contrast to ICs (which, BTW, can also be analog; many analog synthesizers have been built with ICs).

AFAICT, they're mainly running those transistors in the linear region.

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