Multiplexing MIDI Output Streams with Arduino

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little-scale: Multiplexing MIDI Output Streams with Arduino. Sebastian writes –

Arduino can easily generate MIDI output data for use with external synths and modules or to take physical events and turn them into control data for use with software synths and applications etc.

Although the Arduino only has one Serial output, it is still possible to use a multiplexer to send multiple streams of MIDI data to multiple devices.

The idea is pretty simple. The Arduino still uses its TX pin for sending serial data, but uses an analog multiplexer to choose where that data is going (say, one of two MIDI outputs for example). The analog multiplexer that I have chosen is a 4051 and can ‘route’ the data to up to eight different places.

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  1. Funny you should mention MIDI… I just finished drawing up a MIDI IO shield tonight. I might have to start from scratch now…

  2. Interesting that you’re discussing this now. I’ve just been reading about the 4051/2/3 analog multiplexers for another project I’m working on. They’re pretty cool and versatile chips!

  3. Funny you should mention serial output. 🙂 You don’t really need the 4051 for this purpose if you step outside of the Arduino environment and do a little coding with WinAVR. You can use the timers inside the AVR to setup a scheduler that can accurately bit-bang serial data to any general purpose IO pin. I just finished a project using this technique and I was very impressed with how reliable the technique turned out to be. I’ll do a writeup to share sometime in the coming weeks…

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