Solid state magic eyes?

[RadioRon]

Hi folks,

i am looking for some nos "magic eyes" tubes and found a very nice video called Arduino EM80-Elektronenröhre Nachbau

https://youtu.be/P1xqQVbae4M
http://radio-bastler.de/forum/showth...99649#pid99649

How does it work? Can somebody explain that type of rebuild?

73 & 55
Ron

[Gulliver]

I wonder if that could actually be used in place of a magic eye, or if he's just using a small LCD screen with a little computer program to do something similar.

I also wish his video was in focus.

[wave solder]

Looking at it the display is an OLED type and going by the title an ATMEGA based microcontroller for controlling it.

[Cobaltblue]

Nice thread here using LED's https://www.vintage-radio.net/forum/...ad.php?t=97804

As Magic eye prices go ever higher lots of clever ideas will appear to replace them.

Cheers

Mike T

[RadioRon]

Here: http://www.radio-bastler.de/forum/sh...d.php?tid=8636

What kind of "rounded" display is used?
It seems to me he can simulate all types of magic eyes with the same chip? Is that right and/or possible?

73 and 55
Ron

[RadioRon]

What kind of "rounded" display is used?

Okay its a special OLED for smartwatches, i found another side of his project.

http://www.wumpus-gollum-forum.de/fo...-58_323_3.html

The EM1-rebuild looks really cool.

[ThePillenwerfer]

There's another one using a PIC here: http://electronbunker.ca/eb/6U5.html

[David G4EBT]

Someone on the forum posted a thread about that design last summer Joe - he'd made one but was seeking ideas as to how to use a green 'diffuser' to make the LED segments look a bit less obvious and more 'retro'. (No useful conclusions ensued and the thread fizzled out). Although I didn't/don't need a magic eye, I was quite taken with the project so printed off the article, obtained all the bits and created a PCB mask for it. That was in June last year.

Ordinarily, I don't bother with any projects that use PICs, because I don't have the equipment, knowledge or desire to get into that malarky as it's yet another diversion in a busy life. Nevertheless, in Jan this year, I got around to etching a board and building it. Then I put it to one side, thinking that at some point, I'd seek help on the forum for someone to program the chip - maybe in exchange for a PCB & chip. Still haven't got around to that, but then I've got form going back to schooldays in the '50s in starting projects then sidelining them, so no surprises there!

I'm not overly keen on the method of mounting the LED array - I dislike Veroboard with a passion, but can think of a more elegant way of doing it. Also, I need to re-visit the mounting of the electrolytic cap which I mounted vertically but it prevents the PCB going into the octal valve base as far as I'd wish, so I'll most likely re-mount it horizontally on the underside of the board. Sometime, whenever, if ever.

Hence, for now, it's on the 'to do list'.

By the way, for anyone contemplating building this project, the ebay seller at the link in the article has to date sold 563 of the green LED arrays, and shows more than ten still available at just $3.50 USD post free. For how long, is anyone's guess.

Pictures below are of the PCB, the built up board and the bits I've got together to finish the project. For anyone who might want to make the PCB, the last picture is of both negative and positive images to create the UV mask. (Sorry, I can't make any PCBs due to time constraints).

Hope that's of interest to someone.

[kellys_eye]

An idea worth investigating......

If you place an LED at the peak of a cone shape - with the wide end pointed towards yourself - and move the LED in/out of the focal point of that cone you will see the spread of light 'move' up and down the inside of the cone as you look at it.

Fit the LED to a speaker coil type arrangement and drive it from the AGC.

Digital purists might drive a small stepper motor (ex floppy drive head movement?) - but the idea is based around the light 'cone' growing and shrinking as it moves in/out the focal plane.

[Radio Wrangler]

Rather ironic, but back in the day, weren't magic eyes fitted as a lower cost alternative to a meter movement?

And there are also 'doll's eye' magnetic indicators used in aircraft electronics.

As far as the high impedance of the AGC line goes, lots of communications receivers got around this by metering the reduction in cathode-current of an AGC controlled IF amp stage.
This technique would also sort the high impedance issue for any solid state replacement.

David