How to create a DMX RGB LED panel?

Matt2468rv · Tue Mar 06, 2018 8:22 pm

In Massimo's video showcasing QLC+ on the Raspberry Pi, he is using a homemade RGB LED panel controlled by DMX. Could anyone share information on how to create one? I would like to create my own and use QLC+ to drive it. I assume it is using a 16x16 matrix of what I presume to be Ws2812b LEDs?

Massimo, if you are reading this then maybe you could share the components you used to make it?

mcallegari · Wed Mar 07, 2018 8:04 am

I basically used WS2801 RGB LED strips. Most of the work is mechanical rather than electrical.
You can choose between SMD and PTH. Examples:
http://a.co/2s2NfF9
http://a.co/enOtoR9

Then you can control them via SPI with a Raspberry Pi

Matt2468rv · Thu Mar 08, 2018 1:07 pm

mcallegari wrote: ↑Wed Mar 07, 2018 8:04 am I basically used WS2801 RGB LED strips. Most of the work is mechanical rather than electrical.
You can choose between SMD and PTH. Examples:
http://a.co/2s2NfF9
http://a.co/enOtoR9

Then you can control them via SPI with a Raspberry Pi

Great, thank you! That's very helpful. What materials did you use to construct the panel itself?

mcallegari · Thu Mar 08, 2018 1:26 pm

I had some very thin steel sheet laser printed and folded. I tried aluminum too but it was painful to handle. Too weak.
Then to cover it, you need to carefully choose the height and the processing of a polycarbonates sheet, that acts as a light diffuser.

Matt2468rv · Thu Mar 08, 2018 6:43 pm

mcallegari wrote: ↑Thu Mar 08, 2018 1:26 pm I had some very thin steel sheet laser printed and folded. I tried aluminum too but it was painful to handle. Too weak.
Then to cover it, you need to carefully choose the height and the processing of a polycarbonates sheet, that acts as a light diffuser.

Interesting! I was actually thinking about using a 3D printer to create the panel. I could even print using a flexible material such as TPU to make a flexible LED panel.

Do you have any ideas on how to make a 16x16 panel that can be driven by a regular DMX plug connection rather than the SPI pins connection on the Raspberry Pi? I'd like to make it so that it's usable via a PC DMX interface as well. I would assume to control 256 total rgb pixels this requires multiple DMX plugs to span two universes? Or an artnet DMX to LED pixel decoder? Do you know what hardware I could use to do this?

janosvitok · Thu Mar 08, 2018 10:33 pm

You may use either raspberry with ola or https://dmxking.com/led-pixel-control/ledmx4-pro, or check ebay for chinese artnet led drivers.

In case of ledmx4-pro, one driver can drive several 16x16 panels (2 per output x 4 outputs) just needs some clever cabling.

Matt2468rv · Fri Mar 09, 2018 5:19 am

janosvitok wrote: ↑Thu Mar 08, 2018 10:33 pm You may use either raspberry with ola or https://dmxking.com/led-pixel-control/ledmx4-pro, or check ebay for chinese artnet led drivers.

In case of ledmx4-pro, one driver can drive several 16x16 panels (2 per output x 4 outputs) just needs some clever cabling.

Ah, thanks! At $134 I think the LeDMX4 PRO is a little too expensive! I may opt for the chinese artnet led drivers or go the SPI route and wire into the GPIO pins of the Pi like Massimo did.

Alternatively, could I do the SPI wiring method and have QLC+ pass through DMX data to the panel? So it would be: external artnet source > QLC+ on RPi > SPI out to LED panel. In doing this, the Raspberry Pi would essentially be acting as a DMX decoder for the LED panel. Maybe another instance of QLC+ running on PC could control the instance of QLC+ running on the RPi? Is this at all possible, or am I wrong in thinking this way?