Teensy 4.0 + DMX + MIDI over USB

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ant

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Hi,

I would like to build a small and simple device using Teensy 4.0 (I know it's probably an overkill for the task but this is what I have) which I could connect to the computer using USB cable and this device would expose two USB devices:

- standard MIDI,
- DMX, which I hope I’ll be able to use with Daslight software.

So MIDI and DMX signals would enter via USB (from Logic and Daslight) and would be forwarded to respective sockets, and sent down to my MIDI equipment and to stage lights. The goal would be to have one dongle instead of two.

Ideally the device should be powered from USB cable. MIDI part seems to be obvious because there are libraries and example showing how to do it. DMX part seems more difficult. I plan to use Teensy DMS library (https://github.com/ssilverman/TeensyDMX/tree/teensy4), but I don’t know a few things:

1. How to add DMX USB support so computer would see it in addition to USB?
2. I’ve read in many threads that I’ll need transceiver for RS-485. That’s fine. But which one: MAX3483 (3V) or MAX487 (5V)? There are many types of them - anyone with 250K baud rate will work?

Does this idea seem generally feasible - especially the USB part?
 
You’d likely have to write a usb driver for the teensy for dmx, most usb>dmx devices have custom drivers for their hardware at least the ones ive used hence why they usually have their own hardware they sell along with the software
 
You’d likely have to write a usb driver for the teensy for dmx, most usb>dmx devices have custom drivers for their hardware at least the ones ive used hence why they usually have their own hardware they sell along with the software

Bummer, that's what I was afraid of. Just checked Daslight and it seems to be working only with their line of interfaces, indeed. Nevertheless, I still can achieve similar result with just MIDI - Teensy would receive MIDI PCs and would send standard DMX data directly to the lights. Of course I would not be able to use Daslight to design the show - would have to describe the show programmatically (which has its advantages as well).
 
In case anyone else would be looking for similar info: I ended up using MAX3483EEPA+ RS-485 - works great on with Teensy 4.0 using 3.3V. Now the hardest part: soldering everything together and building enclosure :)
 
It’s possible to have the Teensy emulate any of the DMX USB serial devices (eg. DMX USB Pro). As long as the software can find or be told the correct comm port (or device on OSX or Linux), then it works great. Just use the `Serial` object to read and write data. I’ve tested such a setup using TeensyDMX coupled with TouchDesigner, and also coupled with OLA. Note that Teensy 4 support is now included in the main branch, currently at v4.0.0-beta.

I was just browsing the daslight.com site and haven't yet discovered details about their USB-to-DMX protocol. Most devices I know of are compatible with the DMX USB Pro standard, which can be found here: https://dol2kh495zr52.cloudfront.net/pdf/misc/dmx_usb_pro_api_spec.pdf. I don't know if Daslight's product uses this, however.

Side note: I'm waiting for some more TeensyDMX usage feedback before transitioning into a non-beta release. Otherwise, it's pretty close to final. I'd love to hear your thoughts on, experiences with, and suggestions for the library.
 
Side note: I'm waiting for some more TeensyDMX usage feedback before transitioning into a non-beta release. Otherwise, it's pretty close to final. I'd love to hear your thoughts on, experiences with, and suggestions for the library.

Thank you Shawn, I decided to go with your library and wrote some code which does simple lights animations. They are triggered via midi signals sent from Logic Pro X. Light show definition is sent to Teensy before each song by means of SysEx midi messages from Logic Pro X as well. Everything works like it should.

As for feedback for TeensyDMX library - I don't have much of it - I included it in my project and it just worked without any glitch so far. Great library and thank you for making it available!
 
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