[sdiy] Alternatives to Faders

[Quixotic Nixotic]

On 8 Mar 2007, at 16:24, Edward King wrote:

> How about level indicator such as 5 greens to 3 yellows to 2 reds?
> Would you be comfortable using that as approximation?
>
> EK

Edward,

They are probably too retro for your masterwork, but Russian IN-13  
bargraph tubes would look great as virtual fader displays. Lovely  
neon. I have some of these tubes and they are great. You can drive  
them with a simple 555 switcher and FET supply. They are easy to  
voltage control and are pretty much linear over their total length.  
They only need 4ma for total deflection.

This circuit works well (ditch the picaxe):
http://www.ledsales.com.au/pdf/in13_driver.pdf

As far as I know there is nothing in the west of a similar nature.  
Russia seems to have an inexhaustable supply of them.

The slightly smaller IN-9s are good too, but lack the secondary  
cathode that aids calibration and makes sure that the glow starts  
reliably at one end. IN-9s take more current, at 12ma each.

IN-9s are available in true neon orange or also in purple argon,  
which looks especially cool.

I throw this into the mix as anyone who is doing a retro synth might  
find a good practical use for these tubes. They are really pretty  
when lit.

Look at eBay item 190089617753 to buy IN-13 in neon.
Look at eBay item 110098333245 to buy IN-9 in neon.
Look at eBay item 330074024575 to buy IN-9 in argon. (shows the two  
side by side)

see also:
http://jkx.larsen-b.com/gallery/NixieProject/dsc01927

Best wishes,

John