[vcf-midatlantic] Any MIDI enthusiasts around?

Bart Hirst louisbhirst at gmail.com
Sun Mar 13 20:25:33 UTC 2022


If you're open to using ws28xx aka "Neopixels" then a wealth of stuff has
been done with them.  For example a google turned this up:

https://www.partsnotincluded.com/how-to-control-anything-on-arduino-using-midi/

p.s. about "how lighting is mapped to midi" IMHO most of the code in the DJ
/ Lighting industry is heavily proprietary and non-OSS.  There's no silver
bullet in the hack-a-day scene, but plenty of one-off projects and code
snippets because as you say midi is well known / supported.

On Sun, Mar 13, 2022 at 4:01 PM ☼ wil lindsay ☼ via vcf-midatlantic <
vcf-midatlantic at lists.vcfed.org> wrote:

> Using an Arduino as a gate with some 6N138 optocouplers would allow you to
> translate the signal from Midi to something like the
> https://github.com/FastLED   Arduino-WS2810 libraries should be
> fairly simple, give or take figuring out the power supplies for your midi
> bridge and the LEDs.
>
> The only real issue in using MIDI would be the lack of match in the specs.
> Midi is built around 0-127 (#0-#7F) where these LED libraries are typically
> 0-255 for each color. I'm sure you could sort something on the arduino like
> The Note (0-127) is an addressable LED and the Velocity 0-127 (doubled) is
> the color, where notes would be expected in a series of three. (R,G, & B).
>
>
> Midi also uses the irritating speed of 31,250baud which normally has to be
> a cludge on an arduino. It might make more sense to just use serial at a
> higher speed and define your own information packets. The SPI speed of
> these LED strips is lightyears faster, and your  arduino code and/or the
> library will typically collect your color commands in a buffer and send
> them a bit delayed. There's a little bit of lag, but even if you're
> synching to music, the human brain has an amazing tendency to make light
> flashing timing "feel" right, even when it's off.
>
> On Sun, Mar 13, 2022 at 2:59 PM RETRO Innovations via vcf-midatlantic <
> vcf-midatlantic at lists.vcfed.org> wrote:
>
> > I am looking to control some RGBW leds (maybe SPI-based strips, maybe
> > individual high power RGBW LEDs, not sure yet) with some of my classic
> > computers.
> >
> > That's pretty easy, no concerns there.  Lots of arduino projects or I
> > can just add in a 6522/6821/etc.
> >
> > But, I thought, instead of just making a hobby project, I should try to
> > design something that would work with classic systems *AND* current
> > gear, and not be so platform dependent.
> >
> > MIDI came to mind, both because the cost to interface is pretty low,
> > cables are cheap, and MIDI is very well supported.
> >
> > Where I am struggling is getting a handle on how to map the ability to
> > set an individual LED color in a strip of say 20 or 60 to the MIDI
> > protocol without just punting and using SysEx msgs. And, I might have a
> > bunch of these strips (more than 16 perhaps, though my initial project
> > only needs 10-12.
> >
> > I am also aware of DMX lighting and MIDI->DMX converters.  DMX XLR-5
> > cabling is a bit pricier than MIDI 5 pin DIN (though the RS485 protocol
> > seems simple enough), so I thought maybe I should just emulate a
> > MIDI->DMX->LEDs in my design.
> >
> > Anyone familiar with MIDI-controlled lighting and how it's mapped to
> > MIDI messages?
> >
> > Jim
> >
> > --
> > RETRO Innovations, Contemporary Gear for Classic Systems
> > www.go4retro.com
> > store.go4retro.com
> >
> >
>


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