Fragile Territories
The four laser projectors are controlled by generative Max patches, creating constantly morphing shapes of light. The Max patches run on two computers, each of them controlling two lasers, and a third computer runs Max4Live to generate sound, using algorithmic MIDI sequencers that play notes and parameters of several instances of the Max4Live Granulator synthesizer. The Max patches and Max4Live talk to each other via a simple UDP network. A lot of gen~ is involved both for synthesis and for the generation of the visual shapes. The visual shapes are basically complex vector graphics, calculated as audio signals at 96kHz and then transmitted to a multichannel DA converter that controls the brightness and color of the laser sources and the movement of the galvanometers inside the laser projectors.
It would be nice to see a few minutes of video to see time scales
video is in the making. i hope to be able to post it in two weeks or so.
Really nice! How did you translate from max to ILDA format?
Hi micron, ILDA is an anlog protocol, ( +-10 Volts for X/Y, 0..10 V for intensity of the lasers ). Some sound cards ( Motu, RME ) offer DC output. All you need to do is having some sort of conversion from what ever max. output volume they deliver to that range. This can be done via a simple OPAmp circuit per channel.
However, I figured out that the Motu Ultralite generates a peak volume of around 7 Volts and that is more than enough to drive the galvanometers ( X/Y ) and the lasers I used where strong enough to be very bright at 70% of their maximum output. Bottom line, I did omit the OPAmp stage and drive the lasers directly from the Motu. It is worth noticing that 96kHz is quite essential here, both for the control of the movement and for the blanking / intensity control. If the soundcard would have supported 192k and my mac minis were faster I would have gone even higher.
Robert, I would love to learn more about controlling RGB lasers with audio signals. How do you output multiple simultaneous points / lines, etc.? Thanks!
Hi meeble, all you can do with lasers is controlling the position of two mirrors that define the (angular) position of the laser beam on an X/Y axis. And you can control the intensity of the laser sources. Drawing a line in a specific color means: creating the desired color by sending the right control voltages to the laser sources. Then you need to create a ramp of the X/Y signals depending on where you want the line to start and end and how long you want the movement to take. Since you only move a single dot of light, you need to repeat those movements as fast as possible. Timing is very essential here and can get quite difficult for more complex shapes, but that's the basic concept.
Hi Robert,
Would you be willing to chat more with me about this process via email? I want to move forward with this very soon,and I have other questions about how you wired the audio outputs to the ILDA cables, etc. My email is: mm AT meeble DOT com. It would be very much appreciated. :)
Hey Robert,
very cool project!
I saw the video on your site and it inspired me to get into Max more :)
Tom
Thanks for sharing this. Much appreciated!
Hi Robert
i wrote a mail to you so here is just an repeat, i appologize if any bothering.
This is .... amazing! i tried sound card method years ago but i failed because of i couldn't generate -24~24V, or -15~15, also may i know how you create the ramp for the x/y movement? i have been search for anyone who knows about particularly this technology for very long, i'll glad to know the answer for any cost...so sincerely, may i know anyway i can contact with you? very very appreciate.... my email is: dontmarryme@gmail.com
Surely you'll need some beefy operational amplifiers to get your voltage that high - even the motus that robert uses don't go so high - I suspect Mr. Henke uses lasers configured to +/-4v or something.
The shapes are drawn using x/y/brightness/colour, if I remember correctly, so what you're seeing is waveshapes and bitcrushes and weird slew in great concert, really.
hi Robert,
...hey,looks great what this project developed into!
(i am the robert that took your "test" last summer,remember? (; )
anyway,looking forward to see the video...
also its quite inspiring that there are soundcards that output DC..
Hi there anyone (Robert/ Others) can simply explain how to connect the MOTU to the mirrors engines?
I have the mathematical formulas prototyped for my show and now I would like to have a laser, I can buy one on Thoman.de like the laseworld series, but they accept ILDA or DMX, would love to use the voltage control... any help? Just how to output Max/MSP's voltage into the laser control...
Thanks
Albertootje, ILDA is voltage control...
Robert explains it a couple posts up from here.
Year
November 7 2012 - January 6 2013
Location
Nantes, France
Author