2014 7

A simple sketch for sending MIDI Data from 5 potentiometers (only 3 in the pic above) connected to the AnalogIns from an Arduino (A0, A1, A2, A3, A4) as CC Values.
The sketch is based on the newest MIDI Library from fortyseveneffects, which has to be installed.

Get the full arduino code here.

Two left hands and no passion nor time for learning piano or guitar? Try out this super simple Arduino Midi-Theremin! This simple Midi Theremin uses a HC-SR04 Ultrasonic Sensor (which is extremly cheap ~2-4€) and produces a MIDI-out signal, analog to the measured distance from an object. Apart from the Senor you only need an Arduino (in this case an Arduino Nano), some wire and some MIDI playing device.

Sourcecode

Find the – still alpha – sourcecode here

Choosing the right optocoppler for your midi-in project (e.g. Arduino)

The headlines almost says it all: when building an midi-input device for an µC-project e.g. an Arduino or an Raspberry Pi project, the first thing the MIDI cable “sees” is the optocoupler. And is important to choose the right one.

A lot of ciruits relate to the “4N28”. This is a passive optocoupler and to be frank it causes a lot of problems in the standard setup which mostly are not identified as an electrical problem.

• no midi input at all
• random loss of midi notes
• random playing of other midi notes

(more…)

Creates a square pulse on Digital out in relation to two potentiometers on A0 and A2. The Pulse generator can be controlled in periode (10ms .. 1024ms) and puls width. It works without PWM and without delay() and is based on the blinkwithout sketch

int state1 = 0; // state of the output1; 0 --> OFF, 1 --> ON
unsigned long currentMillis = millis(); // derive actual timestamp
unsigned long startMillis = millis(); // derive actual timestamp

void setup() {                
  // initialize the digital pin as an output.
  pinMode(3, OUTPUT);     
  pinMode(13, OUTPUT);   
  
  //////////////////////////////
  
  digitalWrite(3, LOW);    // turn the output off 
  currentMillis = millis(); // derive actual timestamp
  startMillis = millis(); // derive actual timestamp

}
   /////////////////////////////
   
void loop() {

  if(currentMillis - startMillis <= pulsewidth_1) {
    state1 = HIGH;
  }
  
  if (currentMillis - startMillis >= constrain(analogRead(A0), 5, analogRead(A1))) // Create the pulsewidth. Read Analog POT at A0, contraint (limit) the amount to maximum periode, more wouldnt make sense
  {
        state1 = LOW;
  }
  
  if (currentMillis - startMillis >= constrain((analogRead(A1)*1.5),10,20000 )) // Create the periode (hz). Read Analog POT at A1, contraint (limit) the amount to minimum 10ms
  {
        state1 = LOW;
        startMillis = millis();  
  }
  
    digitalWrite(3, state1);
    currentMillis = millis();

}