Add code sample.

README.md

@@ -7,3 +7,20 @@ Cherry MX breakout board for Arduino, RaspberryPi and other boards.
 ![back](/images/v01_back.png)
 
 Order here: https://oshpark.com/shared_projects/PogDjaIS
+
+```arduino
+const int buttonPin = 10;
+const int ledPin = 11;
+
+void setup() {
+  pinMode(buttonPin, INPUT);
+  pinMode(ledPin, OUTPUT);
+}
+
+void loop() {
+  // The switches are equiped with pull-down resistors. So if the
+  // button is pressed, you read a HIGH, if the button is released
+  // you read a LOW.
+  digitalWrite(ledPin, digitalRead(buttonPin));
+}
+```