[sdiy] DIY Optical organs.

[CCartCat at aol.com]

You've checked out www.optigan.com?  Dunno how much tech info's there, but 
worth a look.

HTH,
Kevin Seward


In a message dated 1/27/03 7:20:41 PM, philgallo at attglobal.net writes:

<< What where the original spec's for the optigon?


Was it linear velocity or did the higher notes encode in the smaller

diameter portion of the record surface?


Your "Tube" idea sounds "conceptually" like a Mellotron since each recording

is of equal length (but with no spring return).  And since no spring return

how will you control rotation (assuming an "attack" "sustain" and "decay")?

Or does the "ORGAN" part mean "bang yer on" "bang yer off"?


Since the original "records" where "printed" they were not "pixelated" but

continuous representations.  Would you OPTO integrate the "BEST QUALITY"

printing into an essentially linear reproduction?


The optigon records i remember had pattern percussion which i thought was

also on the record.


interesting project, basically an analog sample playback system.


regards,

p


 Hi.

I'm a fan of the old optigan organs, and after despairing of finding one in

Wales, have decided to have a go at building one. The principle looks

straight forward, and I can code a little, so I think I can make something

similar using a computer to generate the tracks.


Rather than attempting to make circular records, I think it will be possible

to print the waveforms onto transparent acetate with a laser printer, and

roll the resulting sheet around a clear plastic tube about 6" in diameter.


I will then put the light source inside the tube, use a motor to turn it,

and use a single hand held photocell to select the tracks.

With a 1400 dpi printer I reackon I could get about 2 seconds of 7k

bandwidth with a pretty low amplitude resolution with about 10 tracks per

sheet.


Anyone tried laser printing waveforms onto acetate? I'm not expecting hi-fi

results. :)

I guess the only way is to try it, but I would be interested to see if

anyone else has had a go, and if they had any advice.

This list looks like a good place to ask! >>