diff --git a/smartapps/garrettgeier/toggle-lights-on-off-using-door-sensor.src/toggle-lights-on-off-using-door-sensor.groovy b/smartapps/garrettgeier/toggle-lights-on-off-using-door-sensor.src/toggle-lights-on-off-using-door-sensor.groovy
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+/**
+ *  Door Sensor Light Toggle
+ *
+ *  Copyright 2017 Garrett Geier
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ *  in compliance with the License. You may obtain a copy of the License at:
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software distributed under the License is distributed
+ *  on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License
+ *  for the specific language governing permissions and limitations under the License.
+ *
+ */
+definition(
+    name: "Toggle lights on/off using Door Sensor",
+    namespace: "GarrettGeier",
+    author: "Garrett Geier",
+    description: "Toggle lights on/off with a door sensor. When the door is opened, the lights will toggle based on the master switch.",
+    category: "Convenience",
+    iconUrl: "https://s3.amazonaws.com/smartapp-icons/Convenience/Cat-Convenience.png",
+    iconX2Url: "https://s3.amazonaws.com/smartapp-icons/Convenience/Cat-Convenience@2x.png",
+    iconX3Url: "https://s3.amazonaws.com/smartapp-icons/Convenience/Cat-Convenience@2x.png")
+
+//main screen options
+preferences
+{
+     //choose the door/contact sensor here.
+	section("When this door is opened")
+    {
+		input "doorToggler", "capability.contactSensor", title: "Select Door Sensor", required: true, multiple: false
+    }
+    
+    // this is the master switch. If this switch is ON, then the lights will turn OFF when the door is opened.
+    // If this switch is OFF, then the lights will turn ON when the door is opened.
+    // Don't care about if the door is closed, this is designed for a normal door which will eventually be shut. :)
+    section("Select the Master switch")
+    {
+    	input "masterToggle", "capability.switch", title: "Master switch", required: true, multiple: false
+    }
+    
+    //based on the master switch, these will turn on or off.
+    section("Stuff you want to turn on/off")
+    {
+	    input "switchesToToggle", "capability.switch", title: "If master is ON, these will turn OFF. When the master is OFF, these will turn ON.", required: true, multiple: true
+	}
+}
+
+//required
+def installed()
+{
+	initialize()
+}
+
+//required
+def updated()
+{
+	unsubscribe()
+	initialize()
+}
+
+// the event we care about, when the door is opened.
+// see http://docs.smartthings.com/en/latest/capabilities-reference.html#contactsensor for device capabilities
+def initialize()
+{
+    subscribe(doorToggler, "contact.open", toggleSwitches)
+}
+
+def toggleSwitches(evt)
+{
+	//log.debug "$evt.value"
+  
+	if (evt.value == "open" && masterToggle.currentSwitch == "off")
+    {
+        //log.debug "Light! Yay!"
+		switchesToToggle.on()
+        masterToggle.on()
+    }
+    
+    else if (evt.value == "open" && masterToggle.currentSwitch == "on")
+    {
+        //log.debug "Kill the lights"
+		switchesToToggle.off()
+        masterToggle.off()
+    }
+}
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