Start of example conversion. Added sleep to MySensors API.

libraries/LowPower/Examples/powerDownWakeExternalInterrupt/powerDownWakeExternalInterrupt.ino

@@ -0,0 +1,33 @@
+// **** INCLUDES *****
+#include "LowPower.h"
+
+// Use pin 2 as wake up pin
+const int wakeUpPin = 2;
+
+void wakeUp()
+{
+    // Just a handler for the pin interrupt.
+}
+
+void setup()
+{
+    // Configure wake up pin as input.
+    // This will consumes few uA of current.
+    pinMode(wakeUpPin, INPUT);   
+}
+
+void loop() 
+{
+    // Allow wake up pin to trigger interrupt on low.
+    attachInterrupt(0, wakeUp, LOW);
+    
+    // Enter power down state with ADC and BOD module disabled.
+    // Wake up when wake up pin is low.
+    LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF); 
+    
+    // Disable external pin interrupt on wake up pin.
+    detachInterrupt(0); 
+    
+    // Do something here
+    // Example: Read sensor, data logging, data transmission.
+}