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DMX out on Raspberry PI

Posted: Thu Nov 29, 2018 3:56 pm
by lotusvball
My raspberry pi recognizes the DMX USB cable but I can not get it to send out DMX signals. It recognizes it as FT232R USB UART (S/N: A9K0MN3Q). I tried a windows system with QLC+ and it works fine but I can not get it to work on the raspberry PI. Does anyone have any ideas. I have attached a screenshot of the Input Screen on the Raspberry PI.

Re: DMX out on Raspberry PI

Posted: Thu Nov 29, 2018 4:45 pm
by Frank
Hi Stephen

Strange! I use the same interface and it works great (for years) ...

I like to help, but I do not know yet where to start ...

Frank

Re: DMX out on Raspberry PI

Posted: Thu Nov 29, 2018 4:52 pm
by mcallegari
If you're using the latest version, it might be necessary to decrease the output frequency to a value between 30 and 40 Hz.
Access from the DMX USB plugin configuration dialog.

Re: DMX out on Raspberry PI

Posted: Thu Nov 29, 2018 4:55 pm
by lotusvball
I am not at my system but is that accessed by double clicking on the plugin?

Re: DMX out on Raspberry PI

Posted: Thu Nov 29, 2018 4:56 pm
by mcallegari
Yes

Re: DMX out on Raspberry PI

Posted: Thu Nov 29, 2018 5:00 pm
by Frank
Hi Stephen,

I took a "screen shot" (by the phone) of my Pi 7" touchscreen and attached it.

One difference is that it's the Universe 1 I use.

Regards
Frank

Re: DMX out on Raspberry PI

Posted: Thu Nov 29, 2018 5:03 pm
by lotusvball
I have tried that also. It did not make any difference.

I will try the frequency change tonight. Thanks

Re: DMX out on Raspberry PI

Posted: Thu Nov 29, 2018 5:26 pm
by Frank
... reducing this frequency to 33 Hz was also very important (for me).

But with the original value the USB DMX interface worked anyway ... Only such a flickering was very annoying, ugly just ...

See also viewtopic.php?f=7&t=12780

Frank

Re: DMX out on Raspberry PI

Posted: Fri Nov 30, 2018 12:59 pm
by lotusvball
Went into the configuration and there is no where to set the frequency. The details of the plugin say the frequency is at 30.

Re: DMX out on Raspberry PI

Posted: Fri Nov 30, 2018 1:03 pm
by mcallegari
lotusvball wrote: Fri Nov 30, 2018 12:59 pm Went into the configuration and there is no where to set the frequency. The details of the plugin say the frequency is at 30.
Then you're not using the latest image 20181110

Re: DMX out on Raspberry PI

Posted: Fri Nov 30, 2018 9:00 pm
by lotusvball
I will double check tonight which image I am using and update it if I am not. Thanks.

Re: DMX out on Raspberry PI

Posted: Mon Dec 03, 2018 1:37 pm
by lotusvball
I did not have the newest release. I updated to the newest release and now I can change the frequency. I tried every value between 30 and 43 and still nothing. I am however able to see that the closer I get to 44 the dmx light on the dmx controller will start to blink rapidly, which is supposed to mean that a dmx single is being received. However still no light activation. This works on my windows system. Is there something I am doing wrong. I did not restart it each time I changed the frequency.

Thanks so much.

Re: DMX out on Raspberry PI

Posted: Tue Dec 04, 2018 8:14 am
by Frank
Hi,

only one additional question:
do you use version 4.12.0 on the Windows (10) PC ...

See also the following thread:

viewtopic.php?f=33&t=12867

Greetings
Frank

Re: DMX out on Raspberry PI

Posted: Tue Dec 04, 2018 3:27 pm
by lotusvball
Yes. I am using 4.12.0 on windows. (DMX out works on my windows system)

Thanks for the link. I will read into it and try some more testing tonight.

Re: DMX out on Raspberry PI

Posted: Thu Dec 06, 2018 4:16 pm
by lotusvball
Still no luck with this. Any other ideas?

More info for you.

I am using this: https://smile.amazon.com/gp/product/B01 ... UTF8&psc=1

to connect to the pi and this: https://smile.amazon.com/gp/product/B00 ... UTF8&psc=1

Re: DMX out on Raspberry PI

Posted: Fri Dec 07, 2018 4:54 pm
by Frank
Hi lotusvball,

please excuse me if I confuse something ...

Two "important" questions:

First: do you use the same components on the Windows PC as on the Raspi?

Second: how do you connect the two components together? Directly using (simple) wires?

As far as I know, you need a (special) driver chip (hardware, such as MAX481) to convert the RS-485 signals to DMX ...

I have a sample link that explains that a bit: https://electronics.stackexchange.com/q ... with-rs485

Bye for now
Frank

Re: DMX out on Raspberry PI

Posted: Fri Dec 07, 2018 7:39 pm
by lotusvball
Yes I use the same components for both Windows and Raspberry PI. I just plug it into the usb port.

Here is how I connect the pi to the dmx decoder: https://stevenbreuls.com/2013/05/diy-us ... -under-10/

Re: DMX out on Raspberry PI

Posted: Fri Dec 07, 2018 7:55 pm
by Frank
... there are some tips and fixes (below the article) described, which suggest that this circuit does not always (reliably) work!

For example, the power supply from the Raspi might not be enough to operate the circuit reliably ...!

Re: DMX out on Raspberry PI

Posted: Sat Dec 08, 2018 6:24 pm
by lotusvball
I am going to try the powered hub as soon as it arrives. Will let you know after I do. Thanks.

Re: DMX out on Raspberry PI

Posted: Sat Dec 08, 2018 6:42 pm
by Frank
This would be my first choice too!