It's a DMX lighting controller based on a music (or any audio) input.
The user can program DMX addresses to be associated with the bass,
mid, and treble bands, then those lights are controlled in realtime
based on the intensity of that band in the input audio signal. (It's
easy to think of it like a simple graphic equalizer which uses DMX to
output the magnitude in each frequency band.)

When we finish the project, we're required to make a web page about
it, which IIRC needs to include a lot of the source. Once that's done
I'll send you a link. (The project's not 100% done yet, but it's
close.)

It's nothing very complicated - it's basically an ADC -> FFT ->
magnitude calc -> DMX. (Plus some analog stuff to filter/bias the
audio signal.) The UI is very simple; we use the display on the eval
board we're using + an external keypad for programming, and we store
the configuration in the flash memory on the eval board.

We're using an Actel (now Microsemi) SmartFusion A2F eval board for the course.

The DMX cores were great because we can write to and communicate with
them as necessary, reducing our interrupt overhead. Before we found
the cores, we had planned to use a UART and implement DMX in software.
That's not hard - I've done it on a little STM8 microcontroller - but
I was concerned that the UART interrupt traffic (and context
switches!) would take a significant amount of processor time. We need
to spend as much time as possible doing the FFT and other DSP stuff -
that's the slowest part of the project by far. The DMX cores let us
dedicate much more time to that!

Chris

---
Chris Dzombak
http://chris.dzombak.name



On Sun, Apr 24, 2011 at 4:48 PM, Sebastien Bourdeauducq
<[email protected]> wrote:
> On Sun, 2011-04-24 at 16:34 -0400, Chris Dzombak wrote:
>> I suppose that makes sense, then. Thanks for clarifying that! The DMX
>> core is working perfectly in our project now.
>
> Cool. By the way, what is that project doing? Can you post a link to its
> source code?
>
>
>
_______________________________________________
http://lists.milkymist.org/listinfo.cgi/devel-milkymist.org
IRC: #milkymist@Freenode
Twitter: www.twitter.com/milkymistvj
Ideas? http://milkymist.uservoice.com

Reply via email to