Hello guys !
I did a module to convert CV to DMX.
I had a few issues during the build but it’s a pretty simple and easy build.
I’m using this console and RGB to blend colors of this light. It uses +5v voltage for light trigger and can be powered from +9 to +12v.
I can also trig it manually and attenuate the output.
There is a buffered splitter for the input and any signal from 0v to +5v (even higher, but it begin to act weird) will trig the light dimmer.
You could also use potentiometer to blend each color.
Not sure if a schematic is needed but don’t hesitate if you have any questions.
About DMX protocole.
We are using a simple DMX LED light. Each light will have different built-in options like ‘sound trigger’, ‘stroboscopic effect’, but in this case will will note use them. So I put mine in ‘3 channel’ position.
3 channel means :
channel 1 : Red dimmer
channel 2 : Green dimmer
channel 3 : Blue dimmer
So, by mixing this 3 colors we could have any color we want. Full on the 3 channels will give us white.
Next, we should adress the DMX channel of our light. As our mixer is pretty basic, it will only speak throught the 6 first channel of the DMX adress.
Meaning the three first channel will be red, green, blue of the machine addressed in channel DMX 001 (in 3 channel configuration), we can imagine having another led light in channel DMX 004. So fader 4,5,6 will control the other light colors.
With one DMX cable, you can control 512 DMX parameters. Moving light for exemple could use like 16 parameters to control movement and internal effects.
A stroboscope, wich only have ‘1’ color will use 2 channels :
channel 1 : intensity
channel 2 : shutter speed
The last parameter that I’m using one the console, is the master fader. And in fact, in this configuration, it’s the only parameter that I’m affecting with control voltage. I chose to mix the colors manually by a simple on/off switch (grounding them or connecting them to internal +5v), and sending voltage through the master fader will control the master dimmer of the light.
DMX console modification
Not sure if I had to, but I bypassed all the slider potentiometers. These are B10k and can easily be replaced by rotary one on a pannel, or even better : CV inputs !
The console provide +5v from an internal 7805 chip to feed the potentiometers. My first idea was to replace the potentiometer by a vactrol but it was not really effective.
Issues
I’m using a simple +9v guitar effect transformer. I wanted to be able to use it on stage with a band I’m working for.
So the tl072 use to split the signal (wich will next go to the filter input of an SH-101) is not feeded by negative voltage. I do not really know what’s happening, but a negative voltage from an LFO will be ‘positivized’. I’m not even sure that this buffer was needed.
+5v/0v/-5v from my LFO result in +5v/0/+9v. A stronger than 5v signal seems to trig all the colors. I have no explanation but it resulted in a lucky accident.
You can see what’s resulting in the video : positive voltage trig the red color and negative voltage (becoming positive voltage) fully trig the three colors giving us WHITE.
I’m pretty sure we could found a cheaper solution using an arduino and DMX convertor but I hate programming 
Cheers.
Robin
