* refactored buzzer concept to UITask

* moved buzzer.h/cpp to helpers/ui

src/helpers/ui/buzzer.cpp

@@ -0,0 +1,54 @@
+#ifdef PIN_BUZZER
+#include "buzzer.h"
+
+void genericBuzzer::begin() {
+    Serial.print("DBG: Setting up buzzer on pin ");
+    Serial.println(PIN_BUZZER);
+    #ifdef PIN_BUZZER_EN
+      pinMode(PIN_BUZZER_EN, OUTPUT);
+      digitalWrite(PIN_BUZZER_EN, HIGH);
+    #endif
+
+    quiet(false);
+    pinMode(PIN_BUZZER, OUTPUT);
+    startup();
+}
+
+void genericBuzzer::play(const char *melody) {
+    if (isPlaying())   // interrupt existing
+    {
+        rtttl::stop();
+    }
+
+    if (_is_quiet) return;
+
+    rtttl::begin(PIN_BUZZER,melody);
+//    Serial.print("DBG: Playing melody - isQuiet: ");
+//    Serial.println(isQuiet());
+}
+
+bool genericBuzzer::isPlaying() {
+    return rtttl::isPlaying();
+}
+
+void genericBuzzer::loop() {
+    if (!rtttl::done()) rtttl::play();
+}
+
+void genericBuzzer::startup() {
+    play(startup_song);
+}
+
+void genericBuzzer::shutdown() {
+    play(shutdown_song);
+}
+
+void genericBuzzer::quiet(bool buzzer_state) {
+    _is_quiet = buzzer_state;
+}
+
+bool genericBuzzer::isQuiet() {
+    return _is_quiet;
+}
+
+#endif  // ifdef PIN_BUZZER

src/helpers/ui/buzzer.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <Arduino.h>
+#include <NonBlockingRtttl.h>
+
+/* class abstracts underlying RTTTL library 
+
+    Just a simple imlementation to start.  At the moment use same
+    melody for message and discovery
+    Suggest enum type for different sounds
+    - on message
+    - on discovery
+
+    TODO
+    - make message ring tone configurable
+
+*/
+class genericBuzzer
+{
+    public:
+        void begin();  // set up buzzer port
+        void play(const char *melody); // Generic play function
+        void loop();  // loop driven-nonblocking
+        void startup();  // play startup sound
+        void shutdown();  // play shutdown sound
+        bool isPlaying();  // returns true if a sound is still playing else false
+        void quiet(bool buzzer_state);  // enables or disables the buzzer
+        bool isQuiet();  // get buzzer state on/off
+
+    private:
+        // gemini's picks:
+        const char *startup_song = "Startup:d=4,o=5,b=160:16c6,16e6,8g6";
+        const char *shutdown_song = "Shutdown:d=4,o=5,b=100:8g5,16e5,16c5";
+
+        bool _is_quiet = true;
+};