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I’m currently working on an ArtNet Node project using a Teensy 4.1 and aiming to build a 3 Universe ArtNet Node with Ethernet connectivity. The goal is to have four DMX outputs organized as follows:

Universe A: DMX outputs 1 and 2 Universe B: DMX output 3 Universe C: DMX output 4

After researching and gathering information from various forums and tutorials, I’ve created a circuit diagram. However, since I’m not an expert in circuit design, I’d appreciate it if anyone could review it and help identify any potential errors or improvements.

If anyone has experience with setting up an ArtNet Node using a Teensy 4.1 or can share advice on DMX or ArtNet implementation, that would be incredibly helpful! I’m especially unsure about the pull-up resistors and grounding for the DMX outputs.

Root Sheet

Transmitter Sheet

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  • \$\begingroup\$ At first glance looks okay. Be aware that much DMX isn't isolated: are you sure you need this? DMX512 is just RS-485, so read Perrin's Art and Science of RS-485 especially the parts about grounding and biasing. I recommend you put your resistors in sockets so you can adjust if necessary. Also: consider connecting the inputs pins and controlling the RE and /DE, so you can do RDM, which is much more useful than you'd have thought. I recommend sockets for the MAX485 chips too, field conditions can destroy them. \$\endgroup\$ Commented Oct 31, 2024 at 16:00
  • \$\begingroup\$ Also: consider making a proper 4-universe system. Hard wiring J1 and J4 to be on the same universe looks unnecessary. (Though I'm no expert in the Teensy's serial ports.) \$\endgroup\$ Commented Oct 31, 2024 at 16:14
  • \$\begingroup\$ DMX transmitters are usually ground referenced and not isolated. Even if you do isolate, why drive two optos with same signal, you could use one opto driving two transceivers. If you are not going to use RDM, why bother putting RDM specific termination with fail-safe biasing? \$\endgroup\$ Commented Oct 31, 2024 at 20:39

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Thanks for the informative article, it was very helpful in understanding the basics of DMX. On the pages I found, it was strongly recommended to isolate the DMX output from the rest, as possible voltage spikes can destroy the Teensy. I don't need RDM because I only run a few dimmers and LED pars that don't support RDM. I decided to output Universe A on one port only and build a 3 port 3 Universe node. I also added a driver between the Teensy and the optocouplers as I couldn't find a maximum current rating for the digital pins, only the recommended 4mA, but the optocouplers need 10mA. I also added some capacitors as I found in this schematic: https://forum.dmxcontrol-projects.org/core/index.php?attachment/13368-tx-4x-001-jpg/

Schematic Root

Schematic Transmitters

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    \$\begingroup\$ This does not answer your question. The enable is now incorrect. And no Type-C device port on your laptop will think that anything is connected of you plug that in. \$\endgroup\$ Commented Nov 1, 2024 at 18:42
  • \$\begingroup\$ Could you help me understand what you mean by "RDM-specific termination" and why the enable setting might be incorrect? I was advised to connect it to ground, but I want to be sure I’m doing it right. Also, could you guide me on how to get the USB-C port up and running? \$\endgroup\$ Commented Nov 1, 2024 at 21:42
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    \$\begingroup\$ RDM is in another specs that adds to DMX. Read them for differences - RDM is bidir and DMX isn't. Who advised to connect enable to ground - I don't see that and it will disable output. How to do Type-C properly has been asked and answeres here multiple times from many aspects so you can read previous questions. Review questions are difficult as they are so open-ended. \$\endgroup\$ Commented Nov 1, 2024 at 21:48
  • \$\begingroup\$ From what I've read, RDM allows you to change DMX addresses remotely, but unfortunately my light doesn't have RDM support, so I left the RDM resistors off the DMX port. - I was advised to do this in another forum. So I checked the Opto datasheet myself and saw that it makes no difference whether I pull it up or leave it unconnected. So which is better? - Okay, I'll have a look at the USB-C questions and the rest will be trial and error. \$\endgroup\$ Commented Nov 2, 2024 at 8:54
  • \$\begingroup\$ Since I will be building the circuit on a breadboard I do not want to use SMD resistors. What kind of resistors should I use (carbon film, metal film or thin film resistors) and what and what tolerances should I choose (or where can I find them in the data sheet)? I have the same question about capacitors. For 100nF I would have simply used ceramic capacitors and electrolytic capacitors for the 2.2uF. Can I do that or should I use different capacitors and why? \$\endgroup\$ Commented Nov 4, 2024 at 6:55

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