Adding a basic example as a demonstration under GSoC 2020

examples/02.Digital/SimpleSiren/SimpleSiren.ino

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+/*
+  SimpleSiren
+
+  Description:
+  Haven't we all used horns / sirens. Just a touch on switch and siren blows.
+  Just a tap back and its stops honking. This library provides just this.
+  A bare minimum framework simulating a siren functioning.
+
+  A buzzer which is connected to digital pin 13 is blown,
+  when pressing a pushbutton attached to pin 2.
+
+  The circuit:
+  - Buzzer attached from pin 13 to ground
+  - pushbutton attached to pin 2 from +5V
+  - 10K resistor attached to pin 2 from ground
+
+  - Note: on most Arduinos do NOT come with a Buzzer on the board
+    hence has to be attached to pin 13.
+
+  created March 2020,
+  by Manthan Admane
+
+*/
+
+// constants won't change. They're used here to set pin numbers:
+const int buttonPin = 2;     // the number of the pushbutton pin
+const int buzzerPin =  13;      // the number of the Buzzer pin
+
+// variables will change:
+int buttonState = 0;         // variable for reading the pushbutton status
+
+void setup() {
+  // initialize the Buzzer pin as an output:
+  pinMode(buzzerPin, OUTPUT);
+  // initialize the pushbutton pin as an input:
+  pinMode(buttonPin, INPUT);
+}
+
+void loop() {
+  // read the state of the pushbutton value:
+  buttonState = digitalRead(buttonPin);
+
+  // check if the pushbutton is pressed. If it is, the buttonState is HIGH:
+  if (buttonState == HIGH) {
+    // turn Buzzer on:
+    digitalWrite(buzzerPin, HIGH);
+  } else {
+    // turn Buzzer off:
+    digitalWrite(buzzerPin, LOW);
+  }
+}

examples/02.Digital/SimpleSiren/SimpleSiren.txt

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+A bare minimum framework simulating a siren functioning.