IN-13 Music Visualizer

[wyager]

Hello all,

I recently finished working on a spectrum analyzer music visualizer based on IN-13 tubes. Full writeup (with some nice pictures and videos) at https://yager.io/vumeter/vu.html .

Source code and schematics at https://github.com/wyager/vumeter

Perhaps of interest to some of you is that all of the microcontrollers were programmed in embedded Rust.

Cheers,

Will

[Dekatron42]

Nice!

Your writeup has convinced me to try KiCad again!

/Martin

[Richard Scales]

Very nice write up. I have been sitting on a project like this for over a year. I have all the parts and have tested the circuit that I intend to use. I shall try and pull my finger out and make some progress. I have been using Teensy to do all the processing and produce the PWM signals for the tube drivers. I'm not a clever programmer but managed to do what I needed in the Arduino IDE. The power and speed of the Teensy makes up for my inadequacies!
Good job, done well.

[newxito]

Great project and very good write-up. Yor describe your hard and software choices very convincingly.

[jörg]

Hello Will,
this is a pretty nice project with a brillant description.
I've finished the same project a while ago and your writeup encourages me to start an advanced project description, too.

My approch uses the Teensy 3.2 Microcontroller and some Op-Amps with a PWM Controller.

The driver board is a quad-layer PCB, designed with Eagle.

Because of the case size, I've divided th 3D print in halfes, then glued together.

I like your LED backlight, thougt to do the same in the next version.

Here is a phote of my setup.

Video could be found on youtube: https://www.youtube.com/watch?v=Brj3YM02ULI

Cheers

Jörg

[wyager]

Hello Jörg, 

That is indeed quite similar! I'm looking forward to reading the description.

Out of curiosity, are you doing a 16-bin FFT with one bin mapped to each tube, or something different?

Also, for clarity's sake, there's no built-in backlight in my design. I just put a photography light on blue and put it off to the right when taking pictures. I thought it contrasted nicely with the orange neon glow. I don't like always having an LED backlight, because it makes the whole thing look like some kind of gaming accessory rather than an unobtrusive audio accessory.

Thanks for the kind words everyone!

Will

[Richard Scales]

Ah exciting - another Teensy user with the same idea  - I would love to compare notes at some point. I think I ended up with 20 bins - happy to share code - as long as no-one laughs!

[Robert]

Here’s Bad Dog Designs version

Thanks

Rob

On 23 Feb 2020, at 13:09, Richard Scales <ric...@scalesweb.co.uk> wrote:



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[SWISSNIXIE - Jonathan F.]

Holy Moly! Thats alot of IC's and potentiometers! Lovely, but amazing to see that all of them could fit inside a tiny package mcu

[Mac Doktor]

On Feb 22, 2020, at 7:14 AM, wyager <will....@gmail.com> wrote:

Hello all,

I recently finished working on a spectrum analyzer music visualizer based on IN-13 tubes. Full writeup (with some nice pictures and videos) at https://yager.io/vumeter/vu.html .

Cool. How many IN-13s did you have to buy to get sixteen that actually worked properly? How many duds were there?

What special tricks did you have to implement in software to get the GOOD ones to behave? I've read that they need to be strobed at say 50Hz. More info would be very welcome.

On Feb 23, 2020, at 1:33 PM, SWISSNIXIE - Jonathan F. <jfre...@gmail.com> wrote:

Holy Moly! Thats alot of IC's and potentiometers! Lovely, but amazing to see that all of them could fit inside a tiny package mcu

Heh. I still have to assemble the tortugascuba thermometer. All discrete and SSI/MSI logic etc.

Terry Bowman, KA4HJH
"The Mac Doctor"

https://www.astarcloseup.com/

“The book said something astonishing, a very big thought.
It said that the stars were suns, only very far away.
The Sun was a star, but close up.”—Carl Sagan, Cosmos, 1980

[wyager]

On Monday, February 24, 2020 at 6:15:32 AM UTC+8, Terry Bowman wrote:

Cool. How many IN-13s did you have to buy to get sixteen that actually worked properly? How many duds were there?

Of the ~24 tubes I've looked at, 1 arrived with a broken leg and 4-5 were obviously out of spec (in that the indicator would not reach the top indicator level). I was able to "rehabilitate" the out-of-spec tubes by running them at ~150% maximum current (so about 6mA) for ~10 minutes.

What special tricks did you have to implement in software to get the GOOD ones to behave? I've read that they need to be strobed at say 50Hz. More info would be very welcome.

The main thing I'm doing is giving the auxiliary cathodes ~200ms to fire up before applying power to the primary cathode. This mostly eliminates any "detached" ionization, where the bar jumps up and moves around freely. I think IN-9 tubes generally require more clever stuff like strobing. If someone were to use my design with IN-9 tubes, they would probably want to increase the cutoff frequency of the PWM RC filter from ~300Hz to ~3000Hz and increase the PWM frequency so that they could more abruptly turn the tubes on and off.