I am fully new to Arduino (even don't have one ... yet), however, I'm looking into possibilities to use both MIDI in/out and DMX together. If I understand correctly the MIDI library (re)uses the UART/COM while the DMX does the same.

I am wondering if it can be used together (e.g. use MIDI in to control MIDI out and/or DMX out).

(Also still checking if I would need some simple MIDI/DMX components or 'full' MIDI or DMX shields/boards.)

  • 1
    Here's a web page I created with photos, code, and detailed instructions: lights4music.com/instructions.html Commented Sep 20, 2017 at 19:57
  • @Lights4Music Thank you very much .... because of memory usage I decided to move to STM32, but later when I also want DMX I'm sure I can use some of the information of your project. Cool project you have btw. and thanks for the link! Commented Sep 21, 2017 at 9:23

2 Answers 2


Yes you can use multiple UART/Serial devices with a single Arduino.

However, there are some things to consider:

The Arduino Uno supports a single hardware serial connection (which is used for programming and debugging with the Serial Monitor). The Arduino Mega supports 4 hardware serial connections.

The arduino environment has a software Serial library that allows for additional Serial connections. However it is worth noting that software serial is slower than its hardware counterpart.

Also, if you want to use software serial, be sure to verify that any shields you want to use will support using a software serial connection.

  • 1
    note that since DMX needs 250kbps and MIDI uses only 31kbps, the MIDI should be the software one...
    – dandavis
    Commented Feb 19, 2017 at 9:08
  • Thanks for the answer and note, this is very helpful ... I guess I have to get used to Arduino, and maybe buy a starter kit to test if a software MIDI Serial solution would work well enough. Just wondering if I can use the hardware serial connection for debugging another way but I will add a new question for that. Commented Feb 19, 2017 at 10:31

The DmxSimple/DmxMaster library does not use serial and will work simultaneously with the MIDI library by 47 Effects. I have used the Sparkfun MIDI shield with the Tinkerkit DMX shield. The trick to stacking them is using tall headers on the MIDI shield and not soldering the XLR connectors on the DMX shield.

Or you can use a Teensy which has multiple hardware serials and more RAM at a good price but requires building a couple basic circuits.

  • Thanks for the answer, good to know both MIDI and DMX can be used. Commented Mar 13, 2017 at 3:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.