EDIT: a third design option would be to add a run method on each button and, instead of only running the tested "pseudo-event" method, save the current state and event in variables, testing those variables in loop() (property button.wasPressed instead of method button.wasPressed(), for example).

PiscaPisca.cpp (the state-machine itself)

#include "Arduino.h" #include "PwmPin.cpp" #include "Beeper.cpp" typedef enum { NONE = 0, RIGHT_LIGHT = 1, LEFT_LIGHT = 2, BOTH = 3 }; class PiscaPisca { PwmPin _left; PwmPin _right; Beeper _beeper; long _timeReference = 0; const int PERIOD = 350; boolean _running = false, _lightState = false; int _sides_to_turn = NONE; public : void configure(int leftPin, int rightPin, int buzzerPin) { _left.configure(leftPin); _right.configure(rightPin); _beeper.configure(buzzerPin); } public : void run() { evaluateBlink(); } public : void toggleLeft() { checkRestart(LEFT_LIGHT); } public : void toggleRight() { checkRestart(RIGHT_LIGHT); } void checkRestart(int lightSide) { _timeReference = 0; // some clever bit-twiddling can never hurt too much: _sides_to_turn = lightSide & ~_sides_to_turn; Serial.println(lightSide); Serial.println(_sides_to_turn); if (_sides_to_turn > 0) { _running = true; } else { lightsOff(); _running = false; _lightState = false; } } void evaluateBlink() { if (!_running) { return; } else { long currentMillis = millis(); if (currentMillis - _timeReference > PERIOD) { _timeReference = currentMillis; _lightState = !_lightState; performBlink(); } } } void performBlink() { if (_lightState) { _beeper.beepIn(); lightsOn(); } else { _beeper.beepOut(); lightsOff(); } } void lightsOn() { if (isLightSet(LEFT_LIGHT)) { _left.on(); } if (isLightSet(RIGHT_LIGHT)) { _right.on(); } } boolean isLightSet(int lightSide) { return (_sides_to_turn & lightSide) == lightSide; } void lightsOff() { _left.off(); _right.off(); } };