Added oscillator with trigger

basics/simple-osc-with-trigger/simple-osc-with-trigger.ino

@@ -0,0 +1,48 @@
+/*
+ * 
+ * Simple (PWM) Oscillator with Trigger
+ * 
+ * A2 = pitch
+ * A1 = note duration
+ * A3 = trigger in
+ * 
+ * 
+ */
+
+bool triggered; // logic: trigered, yes or no
+#define SPEAKER_PIN 11 
+int noteDuration = 100;
+
+void setup() {
+  // set pin 11 as output
+  pinMode(SPEAKER_PIN, OUTPUT);
+  Serial.begin(9600); // debugging (see if trigger is registered)
+}
+
+void loop() {
+    int input3 = digitalRead(A3); // read analog pin 3 (trigger)
+    int noteDuration = analogRead(A1)/10; // read analog pin 1 (note duration)
+
+    //  trigger 
+    if(input3 && !triggered) {
+    Serial.println("I hear a trigger!");
+    Serial.println(noteDuration);
+    
+    for(int i=0;i<noteDuration;i++){  
+        digitalWrite( SPEAKER_PIN, LOW );
+        delayMicroseconds( analogRead(A2)*10); // wait 
+        digitalWrite( SPEAKER_PIN, HIGH );
+        delayMicroseconds( analogRead(A2)*10 ); // wait 
+        triggered = true;
+        delay(1); //playtime of the osc note: this numer * noteDuration milliseconds
+    }
+    
+
+    }
+    else if(!input3 && triggered) { //if there is no reading on input3 and condition triggered is true (aka sound is playing), set triggered to false, aka stop playing 
+      // STOP WHEN NO TRIGGER IS PRESENT (or do something else ;)
+      triggered = false;
+ 
+    }
+
+}