I'd like to find a simple way to control the lights in our local theater. We have panels and everything, but I'd to experiment with the way I can control the colors of the lights. I'm a web developer and interface designer by profession, so I'd like to 'design' a Web-like interface for this.
Now I wonder: could it be possible to use the audio-out of my computer and/or telephone to send a DMX512 signal?
Every 'command' could be a 'pre-recorded' sound, stored in a WAV. "Dimmer Number 5 To 256!" could then be, conceptually, an iTunes song.
I'm not worried yet about how to couple the devices. I believe it must be doable using op-amps or optical coupling.
I am worried about the 'frequency'. Could I indeed create 250 kHz signal that would make it all the way to the audio-out? Would the signal 'survive'? (250 kHz signal is based on the 4 micro second width of a bit in the DMX512 signal).
Best Answer
Not possible. Your audio card has DACs that run at a maximum sample rate of 48 ksps, possibly up to 192 ksps if you have a really expensive professional card. At 48 ksps, the maximum frequency you can synthesize is 24 kHz.
I suggest looking at this libary: https://pypi.python.org/pypi/dmx/1.0 . It is a python interface to a standard USB to DMX bridge box. And here is a cheap USB to DMX cable that should work with that library: http://dmxking.com/usbdmx.
This may also be a interesting project to look at: http://www.openlighting.org/ . It seems they use a client/sever architecture to connect applications to DMX universes, and it works with a wide variety of USB DMX adapters.