Change the function to:
int controlChange(byte channel, byte pin, byte prevVal, byte controller)
{
int currVal = analogRead(pin);
if(abs(currVal - prevVal) > 5)
{
Serial.print(channel, BYTE); // MIDI control change; channel
Serial.print(controller, BYTE); // MIDI controller
Serial.print(val, BYTE); // MIDI controller value from potentiometer
delay(5);
}
return currVal;
}
Change the calls to:
sonsor0Value = controlChange(0xB0, sensor0Pin, sensor0Value, 0x07); // VOLUME
It really isn't magic. It's simple logic.