This is true. Iām wondering how you would account in a smart app for a āfakeā non-motion event though.
(iām not trying to prove my code or anything, i know it works in my homeā¦ nor am i trying disprove yoursā¦ i have a genuine interest in how you would account for this.) 
My code would definitely work for the general someone is taking a pee or doing their hair scenario thoughā¦ lol
If someone is motionless for large periods of time in the bathroom i canāt help you lol 
I am just doing this as a challenge. I gave up on trying to figure it out once before, but this post has sparked my interest in it. I think I have a solution that might work, but I wonāt know until I get some actual code.
I think that the only way to stop a āfakeā non-motion would be to make it dependent on the door sensor being at the very least open a 2nd time in a specific time space.
Letās say a person went into the bathroom closed the door and is taking a bath, if the motion sensor doesnāt see motion but the door was never open again after being closed then it should not make an action
This would work in most casesā¦ But then someone opens the door to grab a toothbrush and it would throw the whole sequence off.
Hence, the challenge aspect of this. The bathroom is probably the hardest room in the house.
Agreed 
Hereās my philosophy when i write an app. I try not to assume for any variable. If i donāt have emperical data about a situation i tend to not write it into an app. This is what I would do.
2.You could use a moisture sensor in the bathtub that would also do the same thing when water is detected. Same thing here. It would over ride the other sensor inputs until no water is detected.
Agreed, but thatās why I have an absolute restart sequence timer for however long I think would be the minimum.
Most importantly as long as my wife doesnāt have the lights turn off on her which I think they wonāt, if the lights stay on because something out of normal occurred than no problem.
P.S. who takes baths anymore? lol!
This bathroom occupancy thing was one thing I wanted to use ST for in the beginning but itās too complicated for our household. In the end, this simple motion switch did it for us and it still works when the internet goes bonkers. I just have to make sure to move the shower door a bit to reset the motion counter.
The problem isnāt the bath lol. Itās that fact that the motion sensor doesnāt sense a person behind the shower door.
Much discussion of trying to determine occupancy in the following topic. It often comes down to whether you want to account for visitors (inlaws? little kids? new girlfriend?) who may not know your light protocols:
Many people will close a bathroom door almost all the way, but not quite, for any of many reasons. Little kids are an obvious example, but there are also people with arthritis who find door knobs difficult, parents listening for little kids in the other room, people in wheelchairs, new girlfriend taking a shower who wants to subtly let you know itās OK to come in, etc.
In your own household, itās up to you whether you want to take all of those into account or not.
Seriously guys! Just ādumpā the idea!
Ok. I got something working. The door scenario described earlier works. The motion detector will turn off the light after a set period of time only if the door is open. Also, if it detects motion when the door is closed, it assumes that somebody is present and wonāt turn off the light until after the door opens and closes again (or is opened and the timer expires). Let me know if this works for you, or if there is some special case I didnāt consider. Cheers!
/**
* Bathroom Lights Automater
*
* Copyright 2015 Eric Roberts
*
* 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: "Bathroom Lights Automater",
namespace: "baldeagle072",
author: "Eric Roberts",
description: "Automate your bathroom lights",
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")
preferences {
section("Bathroom Setup") {
input "doorContact", "capability.contactSensor", title: "Door Contact Sensor", required: false, multiple: true
input "motionSensor", "capability.motionSensor", title: "Motion Detector", required: false, multiple: true
input "mainLights", "capability.switch", title: "Light", required: true, multiple: true
input "timeout", number, title: "Timeout in minutes if door left open", required: false
}
}
def installed() {
log.debug "Installed with settings: ${settings}"
initialize()
}
def updated() {
log.debug "Updated with settings: ${settings}"
unsubscribe()
initialize()
}
def initialize() {
subscribe(doorContact, "contact.open", openHandler)
subscribe(doorContact, "contact.closed", closedHandler)
state.out = true
}
def openHandler(evt) {
log.debug("Open - state.out: ${state.out}")
unsubscribe(motionSensor)
subscribe(motionSensor, "motion", openMotionHandler)
mainLights.on()
if (state.out) {
state.out = false
} else {
state.out = true
}
}
def closedHandler(evt) {
log.debug("Closed - state.out: ${state.out}")
unsubscribe(motionSensor)
unschedule()
subscribe(motionSensor, "motion.active", closedMotionHandler)
if (state.out) {
mainLights.off()
}
}
def closedMotionHandler(evt) {
log.debug("closed motion")
state.out = false
mainLights.on()
}
def openMotionHandler(evt) {
log.debug("Motion - evt.value: ${evt.value}")
if (evt.value == "active") {
mainLights.on()
unschedule()
} else {
runIn(timeout.toInteger() * 60, timedout)
}
}
def timedout() {
log.debug("timedout")
mainLights.off()
}@baldeagle072 I think its great, only thing I would want to do is be able to assign the time of day when the app should run. Im sure there will be a situation under which something will need to be changed, but currently I cant imagine what it could possibly be.
You can set which mode it runs in at the bottom of the preferences page
The enerwave ceiling mount motion sensor does a fabulous job of dealing with that.
I think @baldeagle072 has solved it. I am working on some tweaks to the code that might prevent some false positives/negatives.
@baldeagle072 I had a chance to run the system, and while by no means am I close to it being as perfect as I thought it would be, I think the main thing Im missing is that the lights donāt turn off if the door is left open. For some reason the feature is not working. Thank You again for the help.
Are you using a motion sensor?
@borya - I think I might have fixed what the problem might have been. If there was no motion registered, but the door was left open, the light would stay on. Replace the openHandler(evt) function with the code below. It should fix it. It sets the timer if there is no motion to begin with. Let me know if that works for you.
def openHandler(evt) {
log.debug("Open - state.out: ${state.out}")
unsubscribe(motionSensor)
subscribe(motionSensor, "motion", openMotionHandler)
mainLights.on()
motionSensor.each {
if (it.currentValue("motion") != "active"){
runIn(timeout.toInteger() * 60, timedout)
}
}
if (state.out) {
state.out = false
} else {
state.out = true
}
}