Rebuilding my old analog console

[Greg]

I can't stress enough that it was Laserium's data channel that really made the difference. Some times you need more than two hands to get the job done. Having RYGB gain, master xy gain, spiral stuff, lissajous rate, offsets, and 48 bits for housekeeping allowed the laserist to do the "lead guitar", so to speak...

Photos of the impressive looking equipment that produced Laserium's data channel can be found here:
https://photonlexicon.com/forums/sho...-CYGN-B/page16

I have some previously unreported information on what these encoder decks were all about, gained through a series of interviews generously given by one of Laserium's incredibly talented directors.

It is reported that these consoles were, from the outset, intended to be a visual equivalent of the Moog modular synthesizer. Many of the show numbers were choreographed by creating a small number of data frame settings using the block of DIP switches, assigning the individual frames 1 per button, and then simply calling up those frames as the song played by pressing the buttons. This was done in combination with the use of twelve console sliders that produced 8 bit signals for dynamic control of various system parameters.

As well, there were triggerable ramp generators with settable thresholds so that parameters would kick in and out while the parameter was varying, and the transitions between stop and motion would not be seen. Also, the timing of beam enables in the original system (before midi) was very precisely controlled by the director.

The answer to my question about what the fancy looking section of the encoder console with the joysticks did, was that that section was never used. Extra functions were conceived of by the console designer(s) that ended up not being necessary for the production of the shows.

[laserist]

For some reason that link kills my log in and the images are not available...

[Kevint]

PERFECT!
I'm not sure i captured all that. My brain thinks visually. Here is a summary of actions:
1) use duel pots for X1Y1 & X2Y2 gains (image size)
2) use pots for X1Y1 & X2Y2 symmetry
Or/and
3) joystick control of X1Y1 &X2Y2 gain (not sure what is meant by equal gain at 10 and variable effect at zero)
4) 4423 4 each - run 4 sines to X1 & X2 summing amps. Run 4 cosines to Y1 & Y2 summing amps.
5) Z rotation (future discussion, need to work out 1-4)
6) data channel (would love to do something like that - future discussion)

I'm going to try and re-layout my schematic with these features. Hope I'm understanding things correctly.

[DZ]

Hi Kevint, I started down the road of building a console quite a few years ago. It has been a very challenging yet rewarding experience. I'm attaching the logical block diagram for my console, perhaps it may help. If you have any question, feel free to ask!

When it comes to zRotation, I found that having the ability to precisely control the image rotation with a sine/cosine potentiometer quite beneficial. I found a company that made the perfect sine/cosine potentiometer but they are no longer in business. More recently, I found this: SCH22 Sine Cosine Potentiometer | Hall Effect | P3 America. Unfortunately, they plan to discontinue this product in April. I placed an order for a few over a month ago to see if they perform as well as the previous one I found. Hoping to have my order in the next week or two and will report back if these are worth ordering for anyone still interested in such a thing. The one that I have from the previous company, with a heavy knob and the flick of a finger, spins for a period of time, which is a nice feature!

[Kevint]

Photos of the impressive looking equipment that produced Laserium's data channel can be found here:
https://photonlexicon.com/forums/sho...-CYGN-B/page16

I have some previously unreported information on what these encoder decks were all about, gained through a series of interviews generously given by one of Laserium's incredibly talented directors.

It is reported that these consoles were, from the outset, intended to be a visual equivalent of the Moog modular synthesizer. Many of the show numbers were choreographed by creating a small number of data frame settings using the block of DIP switches, assigning the individual frames 1 per button, and then simply calling up those frames as the song played by pressing the buttons. This was done in combination with the use of twelve console sliders that produced 8 bit signals for dynamic control of various system parameters.

As well, there were triggerable ramp generators with settable thresholds so that parameters would kick in and out while the parameter was varying, and the transitions between stop and motion would not be seen. Also, the timing of beam enables in the original system (before midi) was very precisely controlled by the director.

The answer to my question about what the fancy looking section of the encoder console with the joysticks did, was that that section was never used. Extra functions were conceived of by the console designer(s) that ended up not being necessary for the production of the shows.

That's interesting. Thanks Greg

[Kevint]

Hi Kevint, I started down the road of building a console quite a few years ago. It has been a very challenging yet rewarding experience. I'm attaching the logical block diagram for my console, perhaps it may help. If you have any question, feel free to ask!

When it comes to zRotation, I found that having the ability to precisely control the image rotation with a sine/cosine potentiometer quite beneficial. I found a company that made the perfect sine/cosine potentiometer but they are no longer in business. More recently, I found this: SCH22 Sine Cosine Potentiometer | Hall Effect | P3 America. Unfortunately, they plan to discontinue this product in April. I placed an order for a few over a month ago to see if they perform as well as the previous one I found. Hoping to have my order in the next week or two and will report back if these are worth ordering for anyone still interested in such a thing. The one that I have from the previous company, with a heavy knob and the flick of a finger, spins for a period of time, which is a nice feature!

Dang! that's impressive. I'll see what I can glean from the drawing. Thank you so much for sharing.

[Kevint]

I do have one sin/cos pot I got from a member of this forum.

[Greg]

Sorry, the link was messed up. For the encoder photos, its: https://photonlexicon.com/forums/sho...-CYGN-B/page16

Actually no it wasn't. That's weird, it seems to work for me. Anyway, it is just page 16 on the CYGN-B thread.

[Greg]

I do have one sin/cos pot I got from a member of this forum.

Technically, you got one from two members on this forum.

[Kevint]

Ok. I haven't tried any of the recommended changes yet. At the moment I'm only running 1 scanner set, so I breadboarded 2 more scan amps and last night I wanted to play around with chopping the beam. I put a blade on a scanner and sent a signal to it from an oscillator and when I turned up the gain, there was major crosstalk noise on my laser image (it really distorted the image). The only thing I could figure out last night was to hook the scanner ground wire directly to the power supply ground and that got rid of 95% of the crosstalk but not all of it. At that point I was able to test the chopper and got some really cool stuff. What I don't understand is that I do not see crosstalk on my xy scan pair. It only showed up when I added a 3rd scanner. The circuits are identical.

Any recommendations on how to get rid of crosstalk?