How to Use SparkFun MIDI Shield: Examples, Pinouts, and Specs

The SparkFun MIDI Shield (MIDI Shield v13) is a versatile add-on board designed for Arduino, enabling seamless integration of MIDI (Musical Instrument Digital Interface) capabilities. This shield allows users to send and receive MIDI messages, making it ideal for music-related projects such as synthesizers, MIDI controllers, and other audio applications. With its user-friendly design, the MIDI Shield simplifies communication with MIDI devices, making it a popular choice for both hobbyists and professionals in the music and electronics fields.

• Building custom MIDI controllers for music production.
• Interfacing with synthesizers, drum machines, and other MIDI-enabled devices.
• Creating MIDI-based lighting or stage effects.
• Developing interactive audio installations or performances.
• Learning and experimenting with MIDI communication protocols.

The following table outlines the key technical details of the SparkFun MIDI Shield:

The SparkFun MIDI Shield uses the Arduino's pins for MIDI communication and additional features. Below is the pin mapping:

1. Attach the Shield to an Arduino Board: Align the shield's headers with the Arduino's pins and press it firmly into place.
2. Connect MIDI Devices:
   • Use the 5-pin DIN connectors to connect MIDI IN and MIDI OUT devices.
   • Optionally, use the 3.5mm stereo jack for MIDI THRU.
3. Power the Circuit: Power the Arduino via USB or an external power source.
4. Upload Code: Write and upload Arduino sketches to send or receive MIDI messages.

• MIDI Baud Rate: MIDI communication operates at a baud rate of 31250. Ensure your Arduino sketch is configured accordingly.
• Isolation: The MIDI Shield includes opto-isolation for MIDI IN to protect your Arduino from voltage spikes.
• Pin Conflicts: Avoid using pins D0 and D1 for other purposes, as they are dedicated to MIDI communication.
• External Power: If using multiple MIDI devices, consider powering the Arduino externally to ensure sufficient current.

Below is an example sketch to send a MIDI note when a button is pressed:

#include <MIDI.h> // Include the MIDI library

MIDI_CREATE_DEFAULT_INSTANCE();

const int buttonPin = 2; // Pin connected to the button
const int note = 60;     // MIDI note number (Middle C)
const int velocity = 100; // Velocity of the note
const int channel = 1;    // MIDI channel

void setup() {
  pinMode(buttonPin, INPUT_PULLUP); // Configure button pin as input with pull-up
  MIDI.begin(MIDI_CHANNEL_OMNI);   // Start MIDI communication
}

void loop() {
  static bool notePlaying = false; // Track if the note is currently playing

  if (digitalRead(buttonPin) == LOW) { // Check if button is pressed
    if (!notePlaying) {
      MIDI.sendNoteOn(note, velocity, channel); // Send Note On message
      notePlaying = true; // Update state to indicate note is playing
    }
  } else {
    if (notePlaying) {
      MIDI.sendNoteOff(note, velocity, channel); // Send Note Off message
      notePlaying = false; // Update state to indicate note is not playing
    }
  }
}

• The MIDI_CREATE_DEFAULT_INSTANCE() macro initializes the MIDI library.
• The button is connected to pin 2 and configured as an input with a pull-up resistor.
• When the button is pressed, a MIDI Note On message is sent. When released, a Note Off message is sent.

1. No MIDI Communication:

   • Ensure the shield is properly seated on the Arduino.
   • Verify that the MIDI cables are securely connected to the correct ports.
   • Check that the Arduino sketch is using the correct baud rate (31250).

2. Button or Potentiometer Not Working:

   • Confirm that the correct pins are being used in the code.
   • Check for loose connections or damaged components.

3. Arduino Not Recognized by Computer:

   • Ensure the correct board and port are selected in the Arduino IDE.
   • Try a different USB cable or port.

4. MIDI Messages Not Received by External Device:

   • Verify that the external device is set to the same MIDI channel as the Arduino.
   • Check the MIDI OUT connection and cable for faults.

Q: Can I use the MIDI Shield with boards other than the Arduino UNO?
A: Yes, the MIDI Shield is compatible with other Arduino boards like the Mega and Leonardo, as long as they have the standard header layout.

Q: Can I use the shield for USB MIDI communication?
A: The MIDI Shield is designed for standard 5-pin MIDI communication. For USB MIDI, additional hardware or software may be required.

Q: How do I test if the shield is working?
A: Use a simple sketch to send a MIDI Note On message and verify that the connected MIDI device responds.

Q: Can I use the potentiometers and buttons for non-MIDI purposes?
A: Yes, the potentiometers and buttons can be used as general-purpose inputs for other Arduino projects.