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02-buzzers_with_transistors/activebuzzer_npn_lowside_switching/activebuzzer_npn_lowside_switching.ino

@@ -0,0 +1,31 @@
+#define PIN_BUZZER_SWITCH 14
+#define PIN_BUTTON        21
+#define PWM_CHANNEL       0
+
+void setup() {
+  pinMode(PIN_BUZZER_SWITCH, OUTPUT);
+  pinMode(PIN_BUTTON, INPUT);
+  // Tutorial had a bug here. Needs to be freq=1000, not freq=1.
+  ledcAttachChannel(PIN_BUZZER_SWITCH, 1000, 10, PWM_CHANNEL);
+  ledcWriteTone(PIN_BUZZER_SWITCH, 2000);
+  delay(300);
+}
+
+void alarm() {
+  float sine;
+  int tone;
+  for ( int i = 0; i < 360 ; i += 10 ) { 
+    sine = sin(i * (PI / 180));
+    tone = 2000 + sine * 500;
+    ledcWriteTone(PIN_BUZZER_SWITCH, tone);
+    delay(50);
+  }
+}
+
+void loop() {
+  if ( digitalRead(PIN_BUTTON) == LOW ) {
+    alarm();
+  } else { 
+    ledcWriteTone(PIN_BUZZER_SWITCH, 0);
+  }
+}