Evan Montpellier

Here is a sweet project form  Evan Montpellier it's a video synth based on VGA converters

here is some info that Evan very kindly provided, the basic concept is very straightforward
"This device uses a very cheap and simple method for modular video synthesis. The camera is hooked up to a composite-to-VGA converter box... This has a VGA cable coming out of it, which I slit open to get at the individual conductors inside. This gives you access to the red, green and blue video signal channels on separate lines, as well as the HSYNC and VSYNC signals."

"found that if you run any of these signals into the trigger pin (pin 2) of a 555 set up in astable mode, you can get the 555 to synchronize its output to the video waveform. I haven't looked at it on a scope yet, but it seems like every time there's dip in the original signal, the 555 resets its duty cycle. This is what's drawing the vertical lines that more-or-less conform to the geometry of the original video signal. I found garden variety NE555s to be a bit slow, and wound up using CMOS-based TS555 chips."

"I'm going to keep developing it in the fall. Future plans include checking out the actual voltage ranges with a good scope and implementing some kind of limiting system along the one used in the LZX Visionary, cooking up some more interesting time-based effects and adding VCAs to give more nuance to the colourization. This approach seems like it could be good for people who want a cheap and simple way to get into video DIY, and to that end I want to write up build instructions once I get everything a bit more stable."


VGA video synthesizer test 2 from Evan Montpellier on Vimeo.