I have a love/hate relationship with MIDI.

More than half the projects I work on require some kind of MIDI interface, and I can *never* remember the hookup. All the diagrams on the web never indicate if the view is from the front, or the back of the connector. *And* I can never find a 220 ohm resistor when I want one.

So….

I thought it was about time I put together reusable MIDI IO module that can be hooked up to any 5v microcontroller.

It boils the pins down to just 4 – +5v, Gnd, In (Rx), and Out (Tx). Parts are two MIDI jacks, 4n25 opto, 220, 100K, 3.3K resistors and a 1N4148 diode.

The good news is I can just re-use this module whenever I need MIDI input or output with an Arduino, a PIC or XMOS processor.

Here are links to the 600dpi etch masks for both top and bottom of a single sided PCB.

Top Mask

Bottom Mask

These can be etched onto copper clad using the ubiquitous “toner transfer” method – the top mask is optional.