DMX general question

Hardware
1

Hi,
i read several threads regarding DMX with WLED (esp32).
I just simply need a signal converter like MAX485 and compile WLED with DMX-support?
Solder a XLR plug to the max485 and then just daisy chain the fixtures?
Did i get it right?

Thanks
Malte

2

I’m just starting to play with the DMX version and a few DMX controlled LED tubes…
From what I have found:

  1. Yes you just connect a RS485 driver to whatever pin you have configured as a DMX output. The cheap MAX485 modules work fine for me and have all the required pins already configured for output (by the pullup resistors) so all you need to do is connect the +5, GND and the DI pin.
  2. The fixture configuration confused me to start but what I found was:
    a) The LED count needs to equal your fixture count
    b) In the DMX settings you configure the channel used by your fixture
    c) All you fixtures need to be the same
1 Like
3

In my case I have a DMX controlled tube with 24 LEDs ( so 72 channels in total, with Ch1 being red, Ch2 being green, ch3 being red, etc)

Under LED Preferences

  • Set my LED length to 24
  • Set my color order to RGB

Under DMX Output

  • Set Channels per fixture to 3
  • Set Start channel to 1
  • Set Spacing between channels to 3
  • Set Channel 1 to Red
  • Set Channel 2 to Green
  • Set Channel 3 to Blue

I can now push any effect to the attached DMX LED tube, set presets just like an attached pixel strip
If I send E1.31 (sACN) then it takes over and the attached LEDs respond as expected…
There is even a handy DMX Map view (in the DMX Output menu) that show what color is attached to what DMX channel

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4

I had to think about that for a while, but yes, I guess it makes sense, as WLED is not (yet) meant for live stage scenes.
Luckily I just happen to have a few identical fixtures.
Thank you!

5

OK, it compiled fine, i see the DMX config.
I tried, lazy as I am, this device: Whadda DMX It has a DMX connector soldered on it. For my opinion it is poorly documented. I made some error and it went up in smoke. Crazy… these little chips can produce perceivable noise :wink:
So, wait again for

6

OK, i just test it with one rgbw fixture.

DMX Preferences:
Set Channels per fixture 4
start channel 1
spacing between channels 4 (that means spacing between fixtures?)
DMX fixtures start LED: 0 ???
Ch1 Red
Ch2 Green
Ch3 Blue
Ch4 White

LED Preferences:
What is the output type? Certainly not WS281x. I can’t find anyhthing about it.

LED length 1
Output WS281x
color order RGB
Start 0 length 1
gpio 16

No light.
I measure 3,3V between PIN 3 and 2
Should it work? Did I mess up differential signals DMX A and B? The board says:
A+ and B-, shouldn’t it be A- and B+?

Any help?
Thanks,
Malte

7

Few things

  1. That DMX interface should work. It needs +5 and GND and the signal connection then needs to be connected to whatever pin you configured in the code you compiled.

  2. Make sure your fixture is set to start at channel 1 and you know what channels it requires. Some of the cheap ones have almost no documentation. Some have a dimmer channel that needs to be set for 255 to enable the light to do anything. It really helps to have a small DMX controller (just 6 or so channels) so you can confirm that you light behaves as you think it does. I have some basic DMX info on my website (https://zappedmyself.com/animatronics/dmx-projects/) and one of the projects is a DMX serial monitor (uses a Arduino Leonardo or Micro) that shows all DMX channels, I find it very handy for troubleshooting. What DMX fixture do you have?

  3. The channel spacing needs to match the number of channels your fixture is using.

  4. LED type doesn’t matter, nor does Color Order. However Length needs to match the number of fixtures.

Essentially WLED will treat each fixture (assuming it has a single RGB channels) as a pixel but it also gives you control over extra DMX channels that a fixture may require to have certain values to operate. Its quite confusing till you get the hang of it. And hopefully this doesn’t confuse you even more.

1 Like
8

Oh. I didn’gt define any pin :see_no_evil:
I have stairville quad par profile 5x8w rgbw, which I once had working with a DMX controller. I know how to set the channels and it starts at 1 with 4 channel mode set.

OK, so compiling and checking the cables again and then build a tester with one spare MAX485.
Thank you!