First working version :

- pots
 - keyboard
 - octave selction

res/tools/hairless-midiserial/ardumidi/examples/from_alsa_to_arduino/from_alsa_to_arduino.pde

@@ -0,0 +1,39 @@
+/*
+  This file is public domain. Use it as you like.
+  
+  This is an example program to showcase reading  with 
+  Arduino the MIDI output from an ALSA sequencer. This simply
+  toggles the Arduino LED whenever a MIDI "note on" or "note off"
+  event takes place.
+*/
+
+#include <ardumidi.h>
+
+void setup()
+{
+  Serial.begin(115200);
+  pinMode(ledPin, OUTPUT);
+}
+
+int counter = 0;
+
+void loop()
+{
+	while (midi_message_available() > 0) {
+
+		MidiMessage m = read_midi_message();
+
+		if (m.command == MIDI_NOTE_ON) {
+			/* 
+			If you want to find out which key was pressed, check
+			the value of m.param1
+			*/
+			digitalWrite(ledPin, HIGH);
+	    } 
+
+		else if (m.command == MIDI_NOTE_OFF) {
+			digitalWrite(ledPin, LOW);
+		}
+
+	}
+}