I made a 60hz 555 timer and fed the output through a inverter to make a very narrow pulse. I can see the timing is almost correct because I can use a trimpot to steady the line on the screen. But I think it requires a very precise pulse length to lock on and without an oscilloscope it's nearly impossible.
Because the 555 puts out a squarewave the inverter output will largely follow the 555 in pulsewith.
Duty Cycle (=pulsewidth) on the 555 can be shortened by adding a diode. This diode changes the capacitor charge time, while the discharge time remains as it was.
Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Sat Aug 07, 2010 2:54 pm Post subject:
I've generated images on old TVs/monitors just using regular synthesizers (no sync generator). I've done this with my nord micromodular.
Down in audio frequencies it is mostly just bands across the screen (which still can be kind of cool when you have it running through a sequence).
With higher frequencies and some tweaking, I got it to start to produce some ghostly and somewhat stable images with more dimension to them. Never did get color out of it though.
Joined: Nov 18, 2007 Posts: 301 Location: England
Audio files: 11
G2 patch files: 1
Posted: Sun Aug 08, 2010 4:40 am Post subject:
tjookum wrote:
Does the cmos cookbook have a suggestion for a circuit to generate those pulses?
It doesn't suggest a circuit for actually generating the sync signals. To get pulses of the correct length it uses RC filters. These are 33k resistors from pins 13 and 5 to 5 volts. Then the V sync signal goes through a 100n cap to pin 13 and the H sync signal goes through a 220pF cap to pin 5. Same idea as the "one shots" here http://www.musicfromouterspace.com/analogsynth/mmlogic.html.
It says the pulses should be 5 microseconds long for H sync and 180 microseconds long for V sync.
Because the 555 puts out a squarewave the inverter output will largely follow the 555 in pulsewith.
Duty Cycle (=pulsewidth) on the 555 can be shortened by adding a diode. This diode changes the capacitor charge time, while the discharge time remains as it was.
I used a online calculator and used 220k for Ra and 10k for Ra to get a 99,6% dutycycle wich I inverted to get the pulse, so I was close but I guess it needs to be a lot more precise.
Quote:
It doesn't suggest a circuit for actually generating the sync signals. To get pulses of the correct length it uses RC filters. These are 33k resistors from pins 13 and 5 to 5 volts. Then the V sync signal goes through a 100n cap to pin 13 and the H sync signal goes through a 220pF cap to pin 5. Same idea as the "one shots" here http://www.musicfromouterspace.com/analogsynth/mmlogic.html.
It says the pulses should be 5 microseconds long for H sync and 180 microseconds long for V sync.
ah yes, thank you for that. Im really close to giving up because all this precision goes against the principles of Lunetta for me, but Ill try this as it looks simple and small.
Another problem may be to actually interface the sound from the lunetta into the video signal, at audio rates there just isn't much happening on the screen. _________________ There he goes. One of God's own prototypes. A high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die.
Hunter S. Thompson movies noise
syncing audio and video wouldn't be hard. using audio by itself may not be interesting, but using the same processes you are using for audio to generate video would be worth it. just use high frequency clocks in the area of high khz low mhz. you can sync the two up by having a universal tempo clock to clock both audio and visual functions. i thinkyou would basically have to have two sets of modules though, so basically two lunettas to get any sort of interesting video. i wish i had my electronicsstuff where i am so i could help you guys work this out.
Hey Guys,
here is my version of this... I build the Video-Combiner and some Oscillators together to get the sync signals and to modulate the incoming signal... Everything above 2Vpp Input shoukd work on this thing, so it is not limited to lunetta builds... Sry that i´ve got no scheamtic for now but this is so simple you can hopefully see out of the layouts....
thanks e45tg4t3 for sharing your progress and that very nicely drawn lay-out!
It looks a little different from mine, but yours doesn't seems to be syncing either.
Does look very cool though, did you tweak any knobs in that video? _________________ There he goes. One of God's own prototypes. A high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die.
Hunter S. Thompson movies noise
Well it doesn´t sync perfectly but as long as it looks nice this doesn´t matter to much to me... if you turn the "Mod Freq"-Knob you´ll get differnt patterns, from big to very fine.. "Vsync" and "Hsync" are to get the right frequency but somehow does this depend on the incoming signal.... "Sens" will vary the Schmitttrigger for the Input Signal... "Focus" varies the Contrast of the Picture... well i hope what i wrote is understandable^^....
I was using quite similar technique's with 556 oscillators and also the 4066 switch. The thing I found a little annoying was that the scrolling and flickering didn't seem to be affected by the audio input.
offtopic:
Over in the circuitbending forum I also saw the CRT oscilloscope mod wich looks amazing but the deadly voltages really scared me away. But today I found this:
operating at 5 to 12V this seems a lot safer and would make a beautifull centerpiece for any synth. They can be found in old 80's camcorders wich must be cheap as hell on ebay these days, even broken ones will do as long as the mini crt is intact.
Not giving up on the composite video though, might have to try your lay out and see how that turns out. _________________ There he goes. One of God's own prototypes. A high-powered mutant of some kind never even considered for mass production. Too weird to live, and too rare to die.
Hunter S. Thompson movies noise
Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Sun Aug 15, 2010 12:59 pm Post subject:
tjookum wrote:
ok, that makes sense.
I was using quite similar technique's with 556 oscillators and also the 4066 switch. The thing I found a little annoying was that the scrolling and flickering didn't seem to be affected by the audio input.
offtopic:
Over in the circuitbending forum I also saw the CRT oscilloscope mod wich looks amazing but the deadly voltages really scared me away. But today I found this:
operating at 5 to 12V this seems a lot safer and would make a beautifull centerpiece for any synth. They can be found in old 80's camcorders wich must be cheap as hell on ebay these days, even broken ones will do as long as the mini crt is intact.
Not giving up on the composite video though, might have to try your lay out and see how that turns out.
That's really nice on that tiny tube. That really would be nice to build into a synth. Uh oh, it gives me an excuse to buy the next old camcorder I see in a thrift store. I see them all the time.
I've built a number of these out of old mini TVs.
It is super easy, you just have to mind where you touch:
And another one built out of an old medical device:
so here´s a little update... the modulation frequency was too low for my taste... so i changed the 10nf capacitor in the lower lefthand corner on the left layout into a 1nf capacitor... here is the new video for it....
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum You cannot attach files in this forum You can download files in this forum
Forum index » DIY Hardware and Software » Lunettas - circuits inspired by Stanley Lunetta
FAQ
Calendar
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
Chat Room
