I am new to breadboard electronics projects. I am looking to do this project but am a bit lost on what all I need parts wise. This is my current parts list:

WAV Trigger
1n914 diode
6N138 optoisolator
2 Resistors
3 M/F Jumper cables
Midi Cable
2 Ports
  1. Are these correct?
  2. What resistors do I use for this project?
  3. How do I connect a midi to a port and what type of port should I buy?
  4. What are the wires circled in the picture below? How are they connecting all the components?
  5. In step 1 what is he closing the connection with? Should I add that to my parts list?

enter image description here


  • 1
    \$\begingroup\$ each of the 5 vertical hole rows are connected together ... the top wire connects the orange lead to pin 8 of the IC .... the yellow wire connects to pin 6 .... etc \$\endgroup\$
    – jsotola
    Jun 16, 2018 at 19:50
  • \$\begingroup\$ What is that connector called? \$\endgroup\$ Jun 17, 2018 at 7:09
  • \$\begingroup\$ you can look that up just as easily as i can .... why do you need to know? \$\endgroup\$
    – jsotola
    Jun 17, 2018 at 19:14

1 Answer 1


The 1N914 diode was state of the art when the MIDI specification was written (over thirty years ago). Nowadays, the 1N4148 is better and cheaper. Any other small silicon or Schottky diode would also work.

The resistor values are shown in the schematic:
(source: robertsonics.com)

Red/red/brown is 220 Ω, red/violet/brown is 270 Ω. (The circuit can be improved with a 10 kΩ resistor between pins 5 and 7 of the optocoupler, and then the 270 Ω resistor can be increased to about 1 kΩ.)

There are different styles of MIDI sockets:

All of them are described as "DIN socket, female, 5 pins, 180 degrees", and are meant to be soldered. The square one could be jammed into a breadboard, with enough force.

Alternatively, you could take apart a MIDI cable and solder two pins to the two signal wires so that you can plug it directly into the breadboard (this is what the linked articel does).

In a breadboard, the five holes in each vertical row are connected together. See, e.g., Sparkfun's How to Use a Breadboard for details.

You could make your own connector wires from AWG 24 hookup wire, or buy premade jumper wires.

This jumper is called a solder jumper; you are meant to apply a blob of solder to connect them.

  • \$\begingroup\$ Thank you for the in depth help! For connecting a midi port, the article only has three ports going into the breadboard, is that a problem? And what are the circled items on the image I have above? \$\endgroup\$ Jun 17, 2018 at 7:07
  • 1
    \$\begingroup\$ There are two signals to the MIDI connector/cable, and this is correct. What you've circled are just pieces of wire. \$\endgroup\$
    – CL.
    Jun 17, 2018 at 8:26

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