Any COM port as DMX

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rdelvax
Posts: 4
Joined: Thu Sep 21, 2017 11:50 am
Real Name: Ronald Delvax

Hi,
I'm new to QLC+, and I was wondering;
Is there a plugin that enables QLC+ to send DMX to any available COM port on the computer?
I can't seem to find anything about this with google.

Apparently FTDI chips are supported, but I have CH340 chips for USB to RS232 with a max485 to send DMX.
Using the UART on my arduino and a max485 it works just fine... and since the difference between RS232 is only the signal level, it should be no problem.

If there is no such option, I would like to submit it as a requested feature, but I can't find information on this on the forum either.
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GGGss
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Joined: Mon Sep 12, 2016 7:15 pm
Location: Belgium
Real Name: Fredje Gallon

Do you plan a large setup? Then you probably will find serious timing troubles as the outcome.
Arduino isn't fast enough to keep track of the required timing IMHO.
All electric machines work on smoke... when the smoke escapes... they don't work anymore
rdelvax
Posts: 4
Joined: Thu Sep 21, 2017 11:50 am
Real Name: Ronald Delvax

The arduino I use has a ESP8566 at 80MHz (can be set to 160) That's plenty fast enough for one universe.
And yes, there is a lot of information on the web how to build an art-net node with that chip, even supporting 2 universes
or one universe with RDM. So the arduino is not the problem (just mentioned it to clarify any UART could theoretically work).

But when I just have my DJ set, tablet and a few lights, it would be a lot easier if I could use an USB-RS485 converter as DMX Out.
I have 5 or 6 of those, and they basically work the same way as FTDI chips, but with a CH340. Windows recognizes them as COM port,
but QLC+ doesn't recognize them as viable DMX port.
So if there is a plugin that uses ANY COM port as DMX out, that would be a HUGE benefit for people with a low budget that like to use QLC+.

Even on an older PC with built-in com port... Add a max485 and you'd have a DMX port.

I don't know how to make plug-ins for QLC+ . If there's a good tutorial about that I might try and make the plugin myself (and post it here if I
get it working ofc.)
Goodsir
Posts: 2
Joined: Wed Feb 28, 2018 7:54 pm
Real Name: Jim Goodsir

Hi there. Did you find a solution for this?
rdelvax
Posts: 4
Joined: Thu Sep 21, 2017 11:50 am
Real Name: Ronald Delvax

Unfortunately I don't have a solution yet.
I did build an art-net node using instructions from instructables.com so I can use QLC+ for my lighting,
but a plugin supporting DMX over a COM-port would still be much appreciated.
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GGGss
Posts: 2662
Joined: Mon Sep 12, 2016 7:15 pm
Location: Belgium
Real Name: Fredje Gallon

And who will be responsible for the DMX timing?
Trying to use a com-port (even in RS 485 mode) is merely a medium. The signals you send over it will have to be 'composed' and there I see your real problem. Who is going to write the driver for it respecting the right and precise timing DMX needs.
All electric machines work on smoke... when the smoke escapes... they don't work anymore
rdelvax
Posts: 4
Joined: Thu Sep 21, 2017 11:50 am
Real Name: Ronald Delvax

Today's computers are fast enough to "just" send a stream of 513bytes at 250Kbps without problems. And even if there are delays, DMX is an asynchronous protocol, so as long as the pause between bytes isn't too long, reception will just pick right back up. Max framerate of DMX is 40 fps, if you drop back to half that, you're still fast enough, even for pixelmapping video...
I'm fairly experienced with building DMX hardware, so I know how sensitive it really is. Using a terminal window to repeatedly send bytes over RS232, and converting the signal to RS485 works fine...
So if I knew how to write plugins for QLC+ I'd do so... The DMX frame is already stored in an array of some kind, all you'd need to do is send break/mark followed by 0x00 and the data from the array...

And I know that not every com port is 250Kbps capable...

It would be a very useful addition to the program, but only if there's someone that's willing and capable of writing this plugin.
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mcallegari
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Joined: Sun Apr 12, 2015 9:09 am
Location: Italy
Real Name: Massimo Callegari
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A UART plugin already exists in QLC+: https://github.com/mcallegari/qlcplus/t ... ugins/uart
At the moment it's only built on the RPi version.
Just enable it and rebuild QLC+
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