DecaBox Does MIDI-Driven DMX Scene Recall

 

[caption id="attachment_208" align="aligncenter" width="300" caption="The DecaBox Universal Protocol Bridge - Click to Enlarge"][/caption] The idea for this firmware personality came from a customer.  He was familiar with our MIDI to DMX Converter, which maps individual MIDI notes and CC messages to specific DMX channels.  However, his application was a bit different, and he required more control.

To wit, "Can playing a single MIDI note recall a stored DMX scene?  And can I switch between scenes by playing different keys on my keyboard?"

The answer, it turns out, is a resounding yes. After some discussion, we determined that for his particular workflow, it would be easiest to design DMX scenes on his PC using a spreadsheet program. (Note that the DecaBox can handily capture multiple live DMX scenes for future playback, but that's a different project). So, we designed a simple template using Open Office's Calc program.  Excel would work fine as well.  Here's a screenshot of some sample scenes: [caption id="attachment_573" align="aligncenter" width="300" caption="MIDI Sceneplayer Spreadsheet - Click to Enlarge"][/caption]

In this case, there are 128 rows, each corresponding to a single note on a MIDI channel.  There are also 128 columns, which reflect 128 DMX channels (#1 - #128) being driven by these scenes.

Row#1 is triggered by MIDI note #1, and would output the DMX values

• CH1 @ 1
• CH2 @ 2
• CH3 @ 3
• CH4 @ 4
• etc

In a similar vein, row #11 (triggered by MIDI note #11) outputs the DMX values

• CH1 @ 11
• CH2 @ 1
• CH3 @ 1
• CH4 @ 1
• etc

And so forth. This spreadsheet is saved as an easy-to-process .csv file on the DecaBox's SD card. Then, the magic firmware takes over. As of today's writing (July 9, 2011), this is Rev1 firmware.  It loads a single scene file and switches between scenes, based on MIDI note commands. Rev2 firmware (coming very soon) will include the following updates:

• Smooth crossfading between scenes, with fade duration based on MIDI note velocity.
• Ability to load separate Scene Files, based on MIDI Program Change messages.

But, we think this is a pretty neat place to start.  Enjoy the short silent video clip below.  Note that it was uploaded in 1080p, so you can expand the screen to see more detail.