I want to make a combined MIDI In/Out/Thru + MDX Output shield, so I can order/design just one shield for all my needs.

It is intended to use the shield for Arduino Mega which has 4 UARTs, and I want to stack multiple of these on top of each other, and use jumpers to select which UART pins will be used for MIDI In/Out (1 UART = 1 MIDI In + MIDI Out).

For the DMX part, I could do the same, not thought about that yet, I probably need one DMX output, so I just use the DMX output of one shield and not use the others (maybe not even solder the components for it).

Also, maybe in the future I want to move to Arduino Due, which is 3.3V, and I might need an alternative routing for some components.

What is the best way to create this flexibility (especially for the UART pin selection)?

I was thinking about the following two solutions:

  • Solder pin headers and use jumpers to make the correct connections; because the device will be transported a lot, I might glue the jumpers.
  • Solder pin headers and I solder small wires as jumpers (like permanent wires).
  • Use resistors to make the connections, 0 ohm like a jumper, and do not solder the other connections.
  • Dip switches.

But maybe there are better solutions I didn't think about.


1 Answer 1


For robust connections like this I like to use normal pin headers, but instead of using push-on jumpers I make wire-wrap connections. A good wire-wrap connection is very reliable.

The disadvantage is that you need to have a wire-wrapping tool and the special wire used with it. As an old timer I happen to have that on hand anyway.

  • \$\begingroup\$ Thanks for this comment ... actually, I have such tool and the wire... I wanted to use it for a big LED project, but I never finished it (as most of my ideas, still in learning phase). But with this project it's an easy way to use it (under 10 connections to make probably, so good for practice). \$\endgroup\$ Aug 4, 2019 at 13:40

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