Added simple LFO example

modules/simple-lfo/simple-lfo.ino

@@ -0,0 +1,40 @@
+/*
+ * 
+ * Simple (PWM) Low Frequency Oscillator (LFO)
+ * 
+  Instead of using the square waves to generate oscillations in the (human) audio spectrum (20Hz-20KHz)
+  You can use low frequency oscillations as 'control voltage': using the PWM HIGH (+5v) and LOW (0v) to trigger other modules 
+  and control their adjustable parameters connected to Analog pins 0,1,2 and 3
+  Most LFO's do reach the audible spectrum when oscillating fast enough ofcourse.
+
+        |
+   HIGH |       ___      ___
+        |      |   |    |   |     50% duty cycle
+   LOW  |  ____|   |____|   |     (50% on, 50 off) Determined by delayMicroseconds()
+        |
+        |____________________
+                TIME
+
+ * 
+ * 
+ * 
+ * 
+ * 
+ */
+
+ 
+#define SPEAKER_PIN 11 //the output pin
+
+void setup() {
+  // set pin 11 as output
+  pinMode(SPEAKER_PIN, OUTPUT);
+}
+
+void loop() {
+ 
+    digitalWrite( SPEAKER_PIN, LOW ); // 0v to pin 11
+    delay( analogRead(A2)*5 ); // wait*10, analogRead gives values between 0-1023, so max wait is 1sec, lets make it ~5sec by multiplying the read value * 5
+    digitalWrite( SPEAKER_PIN, HIGH ); // +5v to pin 11
+    delay( analogRead(A2)*5 ); // wait*10, analogRead gives values between 0-1023, so max wait is 1sec, lets make it ~5sec by multiplying the read value * 5
+
+}