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Flip Dots !

A project log for YGREC-РЭС15-bis

YG's 16bits Relay Electric Computer, rebooted

Yann Guidon / YGDES 04/11/2017 at 06:3213 Comments

While rumaging through my stash, looking for electromagnets, guess what I found ?

Yes, memories from Active Surplus, a now closed Toronto surplus store. Damn, I miss you guys...

4 individual flip dots, 10×10mm, that flip at about 1.5V and 70mA (they are measured at 19.2 ohms).


I might use them for showing status (like Z and C flags) and they are easily interfaced in a CCPBRL way : one leg to 0V, the other leg tied to a capacitor (it worked with 100µF under 3V but 470µ is better) that swings from 0 to 3V... or something like that. Hysteresis is built into the system (through ferrite that stores the magnetic flux) so there is no need to maintain a bias current.

Which makes me think...

Without the need to provide bias, a completely electromechanical calculating machine would need no static/constant power !

Discussions

Dylan Brophy wrote 04/11/2017 at 13:22 point

I like the idea of using the flip dots as indicators. They are such cool displays ;)

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Yann Guidon / YGDES wrote 04/11/2017 at 23:41 point

Yes, indeed !

I have only 4 so I must choose wisely.

OTOH I have some hundreds of "Glühbirnchen" (tiny incandescent lamps) which would be awesome, if only they didn't draw 50mA@3V. Displaying the whole register set's values in binary would consume 12A/ or about 40W...

Now that I think of it, maybe I have to use one flip dot array to display the register set, but I have only 2 arrays that I dedicated to the memory, and the dimensions are not suitable (16×28, I need 18×16).

I also consider the Lixie approach or something similar...

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Dylan Brophy wrote 04/12/2017 at 01:37 point

Oh yes, the Lixie is very cool. And very affordable. It has a modern look though (at least to me).   If you want that, cool, but I know some people want a retro/nixie look.  It's all the experience of inventing and learning though, isn't it?

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Yann Guidon / YGDES wrote 04/12/2017 at 01:45 point

Nixies would be interesting though I have doubts about practicality... And I have not seen hexadecimal Nixies yet (and I don't want to do octal :-D)

The look is only one part though. I try to design a sort of playground that is pretty safe, so no high voltages or temperatures.

For now I ponder about the practicality of doing a quadruple Hex=>7 segments decoder to display the Imm16 field :-D

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K.C. Lee wrote 04/12/2017 at 02:03 point

>And I have not seen hexadecimal Nixies yet (and I don't want to do octal :-D)
I have a twenty 14 segments +comma/dot display.  It was from an old pinball machine.

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Yann Guidon / YGDES wrote 04/12/2017 at 02:26 point

@K.C. Lee I maybe have used the wrong word then, I was thinking about stacked digits

https://en.wikipedia.org/wiki/Nixie_tube

Or something like this


or 

https://www.tindie.com/products/connornishijima/lixie-an-led-alternative-to-the-nixie-tube/

I was not thinking about VFD :-)

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K.C. Lee wrote 04/12/2017 at 02:43 point

It is the technology not the form.

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Yann Guidon / YGDES wrote 04/12/2017 at 03:11 point

For the form and technology, I will let common sense (parts count and power consumption) decide.

I'm not sure of the right trade-off :

* 7-segments light several segments at the same time but require less segments.

* unary require 2× more display points but only one at a time

I can deal with diode matrices, though I'll need to wire 4 of them :-D

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K.C. Lee wrote 04/12/2017 at 03:22 point

Make a backlit wheel of digits out of a PCB driven by modified relay with ratchet.  It would fit in better with the electro-mechanical theme.

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Yann Guidon / YGDES wrote 04/12/2017 at 03:36 point

Hahahaha :-)

I had considered making a crude 4-bits DAC and labeling a needle ammeter, or something like that...

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Mark Nesselhaus wrote 04/11/2017 at 07:13 point

Wonder if these could be made DIY at home, perhaps larger.

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Yann Guidon / YGDES wrote 04/11/2017 at 07:18 point

more or less, the principle is pretty simple :-)

* find a permanent magnetic material, make a very thin and lightweight "dot"

* find hysteretic material, some ceramic/iron/ferrite/whatever and make a U

* wind a magnetic coil around the U so you can control the magnetic field in the ferrite

* pass some current in the coil to reverse the stored magnetic field => the magnet will align and flip !

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Mark Nesselhaus wrote 04/11/2017 at 08:01 point

Yeah, thinking along those lines, more worried about building something like that with my fat fingers :-) might have a go with it at that :-) 

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