Anaglyphic 3D with Lasers

[marksmartus]

I bought a MOTU Ultralight audio interface to use for this project specifically because it has DC coupled outputs.

https://www.sweetwater.com/sweetcare...re-dc-coupled/

[marksmartus]

I already have the beam blanking working. You can do almost ANYTHING in Reaktor. LOL In the video, sometimes the blanking is on, like when the cube is showing. But for getting the continuous curly lines I turn the blanking off. With it on, you get dotted curly lines, which are also cool.

At the moment I have 4 outputs going out of the sound card: X, Y, blanking, and eye selection. The blanking and eye selection is done by TTL chips on a protoboard in response to these signals, using an inverter for selecting the other eye, and 2 AND gates to control what color happens in each eye state. But I realized I can accomplish the blanking and eye selection in software by just turning the R, G, and B voltages on and off. I didn't realize that initially. So I will be able to eliminate the TTL chips.

[marksmartus]

Here, you can see it drawing curvy lines with the blanking on, then I hit the button on the screen to turn blanking off and they become continuous.

https://www.youtube.com/watch?v=4AtjZAmS8Gk&t=145s

I just realized the sound doesn't change because the audio is taken from a point in the chain before the blanking happens. I should try listening to the signal with blanking and see what that sounds like. Hopefully not as nasty as the 10K pwm.

[marksmartus]

I think if you download the free version Reaktor Player, then you can download this thing I posted in the user library a while back for doing 2D vector images:

https://www.native-instruments.com/e...try/show/6857/

I did this first, then in 2020 figured out how to compute left and right images for 3D. In December, a friend suggested I could do this with lasers, so in the last week I got the MOTU audio interface and the laser projector.

My blanking signal IS lined up with the selector that is picking which 3D coordinates are in use. The "on" (not blanking) signal goes low, then a new line gets selected, then there is a short delay waiting for the mirrors to move, then the laser is turned on again. Without that, this cube had extra slew marks on it:

https://www.youtube.com/watch?v=4AtjZAmS8Gk&t=119s

[TheHermit]

I think if you download the free version Reaktor Player, then you can download this thing I posted in the user library a while back for doing 2D vector images:

https://www.native-instruments.com/e...try/show/6857/

I did this first, then in 2020 figured out how to compute left and right images for 3D. In December, a friend suggested I could do this with lasers, so in the last week I got the MOTU audio interface and the laser projector.

Very cool! Thanks for sharing. Reaktor looks like a very promising solution for adding vector animations to my T4 Laser Synth, which has 6 audio line inputs that could potentially pass Reaktor's X/Y vectors from the computer's audio outputs through the Teensy for manipulations, then out it's audio DACs to ILDA and the projector... all doable.
Of course, once that's accomplished, the computer will need 3 more audio outputs for full RGB per vector point... unless there's a way to pass all 5 signals from Reaktor to the Teensy via USB or store them onto uSD. Lots to learn.

My blanking signal IS lined up with the selector that is picking which 3D coordinates are in use. The "on" (not blanking) signal goes low, then a new line gets selected, then there is a short delay waiting for the mirrors to move, then the laser is turned on again. Without that, this cube had extra slew marks on it:

https://www.youtube.com/watch?v=4AtjZAmS8Gk&t=119s

YES! Those cubes look great. Well done!
Thank you for illuminating my path forward, Mark.
BR
Roger

[marksmartus]

I've used Reaktor to send and receive MIDI from a Teensy, but don't know if you can do audio.

[Cassy0110]

This is a very interesting experiment, thank you for sharing, no I haven't tried it.

[marksmartus]

Hi all.
I got some dimmer circuitry working for the Laserworld projector (which normally just reacts to R, G, and B inputs on the ILDA connector as either on or off). It uses a single LM339 comparator chip. Pretty cool. You can make an oscillator out of one comparator stage:

https://theorycircuit.com/lm339-oscillator-circuit/

Then I use the other 3 stages on the chip to do the pulse width modulation for the red, green, and blue signals. I tweaked the above circuit to run at a much higher speed and put out a triangle-like waveform that extends from about 0-5V. 0-5V control voltages coming from Reaktor via the MOTU audio interface decide the threshold for the PWM on the other 3 stages of the chip. The laser diodes have a very small region of pulse widths within which the transition from off to full brightness happens, so with the Reaktor software I am setting the maximum and minimum values, which aren't very far apart. You get an effect kind of like the transporter on the original Star Trek. LOL. The lines start out as cloud of flickering dots and then materialize.

Somehow in the process of doing that, I broke the 3D effect, but I'll figure that part out. I'm hoping to use this at a concert I have in April with Joy Yang's group The Interdisciples:

https://www.visitchampaigncounty.org...ts?event=17281

At the above gig in December, I used Reaktor to project 3D shapes through a video processor, but it was kind of monotonous. With that setup it was 3D, but I could only do straight lines. I should be able to do much more nuanced things with the laser projector.

I'll keep you posted.

Mark Smart