More notes
using a potentiometer

User Interfaces for music and sound

Alternative musical instrument user interfaces can make use of various electronic components. Buttons, switches, keys, etc. are mostly likely "digital" interfaces - they are either on or off.
"Analog" interfaces can provide multiple values based on mechanical position or other physical property (temperature, pressure, magnetic field, ...)

A simple analog component is a potentiometer.
Let's look at this tutorial: https://www.electronicshub.org/how-potentiometer-works/

• In the Arduino IDE

  • File > Examples > Built-in examples > 0.1 Basics > ReadAnalogVoltage
    (Or, you can copy/paste the code below into a new sketch (File > New, select all, delete)

/*

  ReadAnalogVoltage

  Reads an analog input on pin 0, converts it to voltage, and prints the result to the Serial Monitor.

  Graphical representation is available using Serial Plotter (Tools > Serial Plotter menu).

  Attach the center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.

  This example code is in the public domain.

  https://www.arduino.cc/en/Tutorial/BuiltInExamples/ReadAnalogVoltage

*/

// the setup routine runs once when you press reset:

void setup() {

  // initialize serial communication at 9600 bits per second:

  Serial.begin(9600);

}

// the loop routine runs over and over again forever:

void loop() {

  // read the input on analog pin 0:

  int sensorValue = analogRead(A0);

  // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):

  float voltage = sensorValue * (5.0 / 1023.0);

  // print out the value you read:

  Serial.println(voltage);

}

Run the sketch

• Sketch > Upload

• Tools > Serial Monitor

  • Set the "baud rate" in the Serial Monitor to 9600

• Move the potentiometer's knob and notice how the value changes.

• You can also use Tools > Serial Plotter to display a graph of the value vs. time.

• Note that other components that output an analog voltage can replace the potentiometer in this example.

Back to MIDI

• Download this sketch: MIDI_pot_note_ProMicro.ino

• Open it in the Arduino IDE, Sketch > Upload

• This sketch adds the potentiometer to the MIDI_keys_ProMicro.ino  sketch we've already seen.
  The potentiometer position selects the MIDI note and the 3 buttons send that note in different octaves.
  Easy to do this -- adding 12 to the note value raises it by an octave (doubles the frequency):
  sendNoteOn(controller+12, MIDI_CHANNEL1);

• Using your DAW or the Online MIDI Editor, try to play a song using the potetiometer and 3 buttons. Challenging?

• Change the buttons to send MIDI on 3 different channels:
  Change this code for each of the 3 buttons, using MIDI_CHANNEL1, MIDI_CHANNEL2, MIDI_CHANNEL3
  sendNoteOn(controller, MIDI_CHANNEL1);
  Using your DAW or the Online MIDI Editor, create 3 tracks and assign them to MIDI channels 1, 2, and 3. Use different instruments/sounds for each of the tracks.
  In Signal (https://signal.vercel.app/), add two more tracks, change their instruments and MIDI channels to 2 and 3.

• Experiment with the buttons and the potentiometer.

• Your ideas?

Do you own thing

Can you think of some creative way to use the potentiometer and buttons to create a different user interface?
Perhaps limit the selected notes to a specific scale? Other ideas?

Do some Arduino coding and create something new.
If you are just learning Arduino, collaborate with someone at the workshop with more experience.