Cheap USB DMX Interface

[CTM Tom]

Hey guys,

Can i first just say - I love this software, it's made some of our installations so much easier. However, one of the things i am battling with at the moment is cheap USB dongles. I have tried a range of them, all of which have had a processor inside them to take the load off the PI - But, the only way i got these "cheap" ones to work was to lower the amount of channels, if i didn't then i would get no output at all or my LED's would flicker. Even with the channels halves the LED's still flicker a bit and then i loose DMX and need to unplug and replug the dongle back in.

Now i know the obvious answer would be to get a better dongle, which I have and it works, but i was just wondering if anyone has successfully used LED fixtures (I use Showtec LED bar 8's for this example) and had no issues. This issue is also happening on my MacBook pro.

The dongles all come up under uDMX in QLC+


Thanks for taking the time to read my thread!

Tom

[mcallegari]

Tom, I renamed your topic with a more meaningful name.

The question is: how many channels are you sending to the USB dongle ?

There are a few parameters you can play with, and they are documented here:
http://www.qlcplus.org/docs/parameterstuning.html

4.2 and 4.3 might be of your interest.
4.5 as well, but use it at your own risk.

If you search the forum, you will hopefully find a few discussions about flickering with Open USB DMX and how users solved/workarounded it.

[CTM Tom]

Hey,

Yeah I should have put more thought into that. I have read some of that stuff, the thing is I didn't want to limit the number of channels, but, looking at it now I may have too!

What would you recommend for a frequency that could potentially stop the flickering?

[Jimmy T.]

Hi Tom,

I use ENT-TEC Pro and there is a utility that changes setting in the dongle as to what speed it sends messages over DMX. That causes flickering if set to slow. Also without a terminator you can get flickering as the signal bounces back.