diff --git a/chicken_door.ino b/chicken_door.ino
new file mode 100644
index 0000000..d1869e8
--- /dev/null
+++ b/chicken_door.ino
@@ -0,0 +1,150 @@
+/*
+ * Open and close the door on the chicken house depending on the
+ * ambient light levels.
+ * Copyright Alex Tucker 2013
+ *
+ */
+
+
+// Enable deep sleep with wake on watchdog interrupt.
+// Based on Donal Morrissey's code at http://donalmorrissey.blogspot.co.uk/2010/04/sleeping-arduino-part-5-wake-up-via.html
+#include <avr/sleep.h>
+#include <avr/power.h>
+#include <avr/wdt.h>
+
+volatile int f_wdt=1;
+
+ISR(WDT_vect) {
+  if (f_wdt == 0)
+  {
+    f_wdt=1;
+  }
+}
+
+void enterSleep(void) {
+  set_sleep_mode(SLEEP_MODE_PWR_DOWN);   /* PWR_SAVE or PWR_DOWN */
+  sleep_enable();  
+  sleep_mode();
+  
+  /* The program will continue from here after the WDT timeout*/
+  sleep_disable(); /* First thing to do is disable sleep. */
+  
+  /* Re-enable the peripherals. */
+  power_all_enable();
+}
+
+#define ONOFF_PIN        2
+#define FWREV_PIN        3
+#define DOOR_CONTACT_PIN 4
+#define BUTTON_PIN       5
+#define PHOTOCELL_PIN    0
+
+#define INITIALIZE     0
+#define WAIT_FOR_LIGHT 1
+#define LOWER_DOOR     2
+#define WAIT_FOR_DARK  3
+#define RAISE_DOOR     4
+
+#define BRIGHTNESS_SIZE  3
+#define BRIGHT_THRESHOLD 600
+
+word brightness[BRIGHTNESS_SIZE];
+int state = WAIT_FOR_LIGHT;
+
+void setupWDT() {
+  /* Clear the reset flag. */
+  MCUSR &= ~(1<<WDRF);
+  
+  /* In order to change WDE or the prescaler, we need to
+   * set WDCE (This will allow updates for 4 clock cycles).
+   */
+  WDTCSR |= (1<<WDCE) | (1<<WDE);
+
+  /* set new watchdog timeout prescaler value */
+  WDTCSR = 1<<WDP0 | 1<<WDP3; /* 8.0 seconds */
+  
+  /* Enable the WD interrupt (note no reset). */
+  WDTCSR |= _BV(WDIE);
+}
+
+void setup() {
+  pinMode(ONOFF_PIN, OUTPUT);
+  pinMode(FWREV_PIN, OUTPUT);
+  pinMode(DOOR_CONTACT_PIN, INPUT);
+  pinMode(BUTTON_PIN, INPUT);
+  digitalWrite(ONOFF_PIN, LOW);
+  digitalWrite(FWREV_PIN, LOW);
+  Serial.begin(9600);
+  state = INITIALIZE;
+  word currentBrightness = analogRead(PHOTOCELL_PIN);
+  for (int i = 0; i < BRIGHTNESS_SIZE; i++) {
+    brightness[i] = currentBrightness;
+  }
+  setupWDT();
+}
+
+void raiseDoor() {
+  digitalWrite(FWREV_PIN, LOW);
+  delay(10);
+  digitalWrite(ONOFF_PIN, HIGH);
+  while (digitalRead(DOOR_CONTACT_PIN) == LOW) {
+    delay(100);
+  }
+  digitalWrite(ONOFF_PIN, LOW);
+  delay(10);
+}
+
+void lowerDoor() {
+  digitalWrite(FWREV_PIN, HIGH);
+  delay(10);
+  digitalWrite(ONOFF_PIN, HIGH);
+  delay(10000);
+  digitalWrite(ONOFF_PIN, LOW);
+  delay(10);
+  digitalWrite(FWREV_PIN, LOW);
+}
+
+word readBrightness() {
+  word currentBrightness = analogRead(PHOTOCELL_PIN);
+  unsigned long total = currentBrightness;
+  for (int i = 0; i < (BRIGHTNESS_SIZE - 1); i++) {
+    brightness[i] = brightness[i+1];
+    total += brightness[i];
+  }
+  brightness[BRIGHTNESS_SIZE - 1] = currentBrightness;
+  return total / BRIGHTNESS_SIZE;
+}
+
+void loop() {
+  if (f_wdt == 1) {
+    f_wdt = 0;
+    
+    switch (state) {
+      case INITIALIZE:
+        if (digitalRead(DOOR_CONTACT_PIN) == LOW) {
+          raiseDoor();
+        }
+        state = WAIT_FOR_LIGHT;
+        break;
+      case WAIT_FOR_LIGHT:
+        if (readBrightness() > BRIGHT_THRESHOLD) {
+          state = LOWER_DOOR;
+        }
+        break;
+      case LOWER_DOOR:
+        lowerDoor();
+        state = WAIT_FOR_DARK;
+        break;
+      case WAIT_FOR_DARK:
+        if (readBrightness() < BRIGHT_THRESHOLD) {
+          state = RAISE_DOOR;
+        }
+        break;
+      case RAISE_DOOR:
+        raiseDoor();
+        state = WAIT_FOR_LIGHT;
+        break;
+    }
+    enterSleep();
+  }
+}