LED matrix video synthesis

coppertraces · Joined: Feb 25, 2015 Posts: 16

I made a sound and light synth designed for drones that has a built in lo-fi video screen made from an 8x8 LED matrix:
Posted Image, might have been reduced in size. Click Image to view fullscreen.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

I designed it to be DIY friendly and open to easy modification and experimentation. It has a very complete set of easily accessible test points and I'm going to make the schematics freely available as soon as I start sending them out into the wild. It would be pretty easy to break out the test points to 3.5mm jacks using just a few resistors for full eurorack patchability. The oscillators can even track one volt/ octave reasonably well if you add a trimmer in series with the exponential pitch CV input resistor. It also uses standard eurorack power connections and runs on +/-12v.

There are a couple more pictures and a longer description on the project page: tiny.cc/videodrone

And here's a demo showing a couple different patches: youtu.be/355hEV0sfGM

PHOBoS · Posted: Sun Apr 12, 2015 11:36 am Post subject:

very nice

I'm actually working on a synth myself with a 5x5 matrix, yours looks more sophisticated though.
It's very useful when you're tuning oscillators.

coppertraces · Joined: Feb 25, 2015 Posts: 16

PHOBoS · Posted: Sun Apr 12, 2015 2:22 pm Post subject:

The display I made uses 2 decimal counters (CD4017) with the outputs of one being inverted and those are connected
to the matrix display (which in my case is made up of seperate LEDs). The signals are connected to the CLK inputs
(only squares), so it's like a really simple XY LED scope.

coppertraces · Joined: Feb 25, 2015 Posts: 16

That's very cool! I bet you could get some interesting effects with that setup... especially with a larger screen and some frequency modulation. Am I right in thinking it should always give you a diagonal line when the two oscillators are tuned to the same frequency? Does it let you visualize other intervals?

PHOBoS · Posted: Sun Apr 12, 2015 3:38 pm Post subject:

PHOBoS · Posted: Mon Apr 13, 2015 8:22 am Post subject:

found it and posted it here

coppertraces · Joined: Feb 25, 2015 Posts: 16

I already got an 8x8 bi-color (red and green) LED matrix to experiment with. I was hoping to make it so you'd have a hue channel and a brightness channel. The hue channel would be driven by a differential amplifier. Higher voltage in would drive the color more green and lower voltage would drive it more red. The color would be continuously variable between the two sweeping through yellow at the center.

I'd definitely like to try RGB too. I'd probably do three separate color channels though since I have no idea how you'd make a hue control that smoothly glides between three colors.

prgdeltablues · Posted: Tue Apr 14, 2015 5:35 am Post subject:

You might be interested in this, which I built in 2013:

http://electro-music.com/forum/topic-58369

Same idea as Phobos, but using four 8x8 LED matrices to give a 16x16 LED oscilloscope.

Peter

coppertraces · Joined: Feb 25, 2015 Posts: 16

That's a cool concept! I just found this one also by Phobos that's similar but a bit smaller: http://electro-music.com/forum/topic-60912.html

commathe · Posted: Tue Apr 14, 2015 10:35 pm Post subject:

coppertraces · Joined: Feb 25, 2015 Posts: 16

That's a lot more information on color space than I would have guessed existed! Shocked

coppertraces · Joined: Feb 25, 2015 Posts: 16

I posted a new video that shows how the LED video screen works and some of the basic things you can do with it. http://youtu.be/y62LyUIY4Oc

And here's another video with some simple experiments and modifications. http://youtu.be/d8OA_Wk6OjE

coppertraces · Joined: Feb 25, 2015 Posts: 16

I got an RGB version working on the breadboard! https://youtu.be/TLT-UP-JsNY

PHOBoS · Posted: Tue Sep 01, 2015 4:45 am Post subject:

Tthat looks great! Razz

I guess I should get me one of those RGB displays to play with.