Re: To Michael Coyle: re: single-digits


>>if I need a water pump for an '86 Ford,

Heh, I've an '85 Toyota... Best $600 car I ever bought for $1000. :-/ Well, it's a long story.

But here in Metropolis, all you want is a "beater" anyway, one that when you look at it, it says: wouldn't you rather steal something that has "fully-functional brakes"?

Uh, this may sound odd, Michael, but I am studiously avoiding looking at any patents. This self-imposed set of blinders may come off Eventually-- I just don't want everybody else's recipes in my head while I'm cooking up my own stew.

Discussing LED displays is okay-- from a "eight-tracks and vinyl" standpoint, anyway; that portion of the technology is sort of moot to my own projects.

Anyway, you've satisfied my curiosity. One inductor per segment makes perfect sense, and I can kinda guess the result of this. Resonating at the driver circuit's pulse frequency, the pulse is stretched out a bit, so the ultimate turn-on time of the segment is a bit longer than the actual pulse duration; in effect, it's as if you gave a bit of "persistence" to the segment while you have gone on to another segment of that digit. Or so I think. But I would be a little leary of this from the standpoint of potential RFI. Hmmm. Do Classics emit much RF noise?

You're right, of course. An LED manufacturer or hybrid chip house would most certainly do a *wonderful* job of making new "old" displays, and I BELIEVE the task of junking, stripping and using old parts to revive collectible calcs is already "de rigeur" within our own clan here at the MoHPC mansion.

I'll stop, then, worrying about the *OLD* calculators. It's only been a way for me, anyway, to try to attract others here to adopt an activist "CAN DO" stance. I don't like to feel alone.

I really hate whining and pawing at the leg of corporations (or anyone), asking them to do what they usedta, because they usedta do it so well. My own past involvements lead to a cynicism about that, while my faith in the creative and collaborative process is still so sure.

Take care-- g.


Hi Glynn,

You're getting closer on the inductors, but...

There's no resonance involved. The inductors are used only as energy-storage devices, nothing more. The power supply charges them and they discharge through the LEDs. It's just RL time constants. The pulse time is short, just a few microseconds, but (presumably) the refresh rate is high.

If I told you any more, I'd have to kill you. :)

I can understand your desire not to contaminate your mind with Prior Art, but just keep in mind that these are EXPIRED patents we're talking about here. All of their IP is now freely available for anyone to exploit, even commercially. End of sermon.

I think we've pretty done the subject of LEDs to death here, so I think it's time to bring this thread to a close. But I'd like to discuss the idea of Open Source calculators and whether there's a possible project to be had. I'll write up some ideas and start up a new thread in the next day or two to see if anyone else seems interested.

- Michael

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