Posted: Sun Apr 29, 2012 5:41 pm Post subject:
a cmos video Synth Subject description: progress reports.
After building my modular drum machine, i started getting into video synthesis. I decided i would do the 25 random cmos challenge again, except this time i would make a video Synth. So i have started down this path. it was difficult at first but now that i have the sync generator working it's very fun.
I am using vga since it is an analog standard. Vga has each color channel on a septate pin. I plan on making a color mixer to split a signal into the different color channels. Lots of stuff to do...
Here's the good stuff, pics!
That's just some of the pictures i took.
I will update my progress here.
UPDATE 2/05/2012:
I have decided for my first foray into video synths that I wouldn't limit myself to the CMOS challenge. So I will be using any chips I see fit. I will still be using CMOS as I think the patterns that can be created with them look good, but i think there are some other things that I need that I dont have available in my 25 random cmos pack i got.
I have a decent working VGA sync generator on a breadboard, i will need to solder it up onto a board. I also need to get a pixel clock working. the pixel clock for 640x480 is about 25mhz, which is quite high and i believe out of the range of the 4000 cmos. i will probably working with a much lower clock, perhaps 1.5625mhz or so.
anyways... more to come. Last edited by Psyingo on Wed May 02, 2012 1:18 pm; edited 1 time in total
Cool stuff... I'm definitely going to follow your progress... any schematics you're willing to share along the way would be welcome. Video is tougher than audio... almost anything can make sounds, but with video, if you don't have sync, you have nothing [stating the obvious for anyone who's delved into such matters].
Cool stuff... I'm definitely going to follow your progress... any schematics you're willing to share along the way would be welcome. Video is tougher than audio... almost anything can make sounds, but with video, if you don't have sync, you have nothing [stating the obvious for anyone who's delved into such matters].
yes, exactly. analog video synthesis seems to be a rather rare art now, not very documented. the lzx and dave jones stuff is commercially available, but there isnt much out there as far as information goes for the DIY'er.
video is a heck of a lot tougher, especially if you have specific results in mind.
i think audio people don't know how easy they have it
sync is certainly is a big hurdle to overcome, and without it you wont get much but a bunch of scrolling lines. fortunately for me, i got my sync generator working yesterday so i was able to generate solid frames.
now comes the process of building mhz oscillators with sync and all the other fast clocked logic.
Kinda straying from the Lunetta topic, but I made a video effects box which perhaps only slightly qualifies as doing synthesis, and it dealt with sync in a rather simple manner. No sync generator.
Basically, I split a composite video signal, sliced it up using a comparator which clocked a 4040 divider, then added a few of the divisions back to the original signal. Since the original signal is still there, the sync is preserved. Limited, but some fun stuff for such a dumb circuit.
Joined: Mar 02, 2010 Posts: 114 Location: Las Vegas
Posted: Tue May 01, 2012 1:05 pm Post subject:
RingMad wrote:
Basically, I split a composite video signal, sliced it up using a comparator which clocked a 4040 divider, then added a few of the divisions back to the original signal. Since the original signal is still there, the sync is preserved. Limited, but some fun stuff for such a dumb circuit.
That's a pretty interesting affect and the simplicity of the approach is interesting -- can you please describe the circuit more thoroughly (or post a schematic )?
Hy Psyingo !!
Great work again !!
Could you give us some informations about your vga sync ? It would be great, cause i've never been able to build it, except using arduino, and i'd like to know how to build it without these kind of stuff...
Some nice photo's there! This is interesting research you are doing. I'm enjoying seeing this develop. I'd like to do something like this myself! It seems like a major project to me. I'm still trying to get a basic logic synth finished! In many ways this is the Holy Grail of 'Lunetta's'
wow !! That's totally amazing !! I've taken a look about the way to interface my lunettas modules with vgas and tvs.. but i haven't found yet the way to have such beautifuls images ( and my best results was to send audio paths into tvs... mmm).
I really wonder how your sync is built, and i just can say BRAVO, it's so great !
thanks for letting us dreaming a bit more.. and giving the envy to go further !
Wow, this image really looks like what I would imagine Lunetta sounds would look like. Impressive work.
And it looks like I totally forgot to post a schematic of my Vidiffektor as requested, although I don't want to dilute this topic with non-Lunetta stuff, and I thought my description of it was pretty detailed. Anyway, I'll dig it out and clean it up....
Would love to see what you are using for sync, most of the things I've tried have been hit & miss or the aforementioned arduino / micro solutions, or this;
looks like you have a really lovely stable image & really broad range of stuff coming out (on a couple of differant monitors?) I really like the layered, textural stuff like this one;
Would love to see what you are using for sync, most of the things I've tried have been hit & miss
Actually the sync im using is a lot more fast and loose than the masochists idea. I'm only using a few 4040's (granted that does take the place of 6 4-bit counters) and some inverting buffers. im not using a vast series of logic gates to derive the pulses such as with the masochists. luckily vga is a pretty forgiving standard!
the sync circuit also has ramp generators, blanking and output buffers.
DGTom wrote:
(on a couple of differant monitors?)
yes, i've been using a few different monitors to test my outputs, one is an lcd tv using the composite input, the other is an oldschool commodore 64 monitor using composite, a sony television using composite, and an ibm vga monitor... the vga by far looks the best, very crisp sharp images! the composite converter introduces a lot of noise into the signal, but it adds a certain grit which is nice in some cases.
i will soon be adding a composite input to the set up so i can process cameras and other input signals. seperate the colors, delay the colors, blur them, etc.
i am deriving a lot of my inspiration from the ems spectre/spectron which i have acquired some diagrams of. unfortunately i cannot share them though. it is a very complex system compared to mine (so far. >)
I might have to give VGA a go, I've mostly been playing around with composite & getting syns that works on more than one TV / Monitor has been elusive, are you using a crystal to generate the clock?
i'm really trying to wrap my head around this video nonsense, but I just perfboarded the circuit below and was wondering what kind of input you all could give me to use this to get a signal i can manipulate with my lunetta.
The schematic is just the sync circuit from a pong schematic i found.
i'm really trying to wrap my head around this video nonsense, but I just perfboarded the circuit below and was wondering what kind of input you all could give me to use this to get a signal i can manipulate with my lunetta.
The schematic is just the sync circuit from a pong schematic i found.
where are the sync pulses coming from in that circuit?
thanks for the reply!
I was going to experiment just feeding in oscillators from my lunetta, but i know you had said you need a really fast clock, so I drew up a crystal oscillator schematic with a divider.
do you think the 40106 oscillators or the crystal will work (i have some 20mhz ones)? What else would you suggest I build to get something out? Also, how does the video input work?
is this pong schematic you got ntsc or pal?
you should look up the timing signals for h and v sync of ntsc and pal. H and V sync need to be rather stable or you will get scrolling. also unless you get a color encoder chip or manage to make your own color encoder you will only get a b/w signal.
i dont think you will get much if you just feed whatever signals into the h and v sync. you need proper timing signals to get a good image. you might get some warbly lines, but it will get boring fast when you can't generate proper shapes and patterns.
here is a short video of some repeating patterns with a voltage controlled differentiator Last edited by Psyingo on Fri Jun 01, 2012 5:16 pm; edited 1 time in total
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