#include // Before running the program below, make sure you set // UseReceiverActiveSensing (optionally UseSenderActiveSensing) in Settings.h to true MIDI_CREATE_DEFAULT_INSTANCE(); void handleError(int8_t err) { digitalWrite(LED_BUILTIN, (err == 0)? LOW : HIGH); } void setup() { pinMode(LED_BUILTIN, OUTPUT); digitalWrite(LED_BUILTIN, LOW); MIDI.setHandleError(handleError); MIDI.begin(1); } void loop() { MIDI.read(); }