Motion Sensor Question

I'm using a Zooz 4-1 mounted just above a shower head to detect occupancy and automatically turn on the bathroom fan. The problem is that, even at the lowest motion sensitivity setting (7) we are still triggering the fan when we walk past the shower (which has a glass door.)

My question is, can a rule be created to check for sustained motion over a period of time? I'm thinking 20-30 seconds of sustained motion would do the trick and eliminate false positives.

Otherwise I'll gladly take suggestions.

My current rule looks something like this:

  • Triggers: Motion is detected [or] Humidity level is above X
  • Actions: Turn on fan; If motion is no longer detected, turn off fan after 10 minute delay

As an alternative, put some white electrical tape on it to reduce the surface of the sphere by half.

You'll cut the 'width' of the detector. Or cut the 'height' depending on the tape orientation :slight_smile:

I have an Iris v2 Motion sensor above my shower and because it's fresnel lens is very small, I just made a tube of tape and slid it over the lens. Did the same with one over my Kitchen sink. You have to stand right up against the sink to trigger it.. and my shower one just extends the light off timer.

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As mentioned above, you could use tape to block some of the "vision" of the motion sensor.

Alternatively in your rules, you could do:


  • Motion Detected


  • If (Private Boolean = True) THEN
  • Exit Rule
  • END-IF
  • Wait 10 sec (or any other amount of time you want)
  • If (Motion Detected) THEN
  • Turn on fan
  • Private Boolean = TRUE
  • Wait for condition (No Motion)
  • Turn off fan -> Delay 00:01:00
  • Private Boolean = FALSE
  • END-IF

I'm not sure if this may trigger multiple instances, but using the private boolean will prevent multiple instances of the rule from running

What if you just used the humidity as the trigger....and a wait condition for the motion to be active to start the fan. and a wait condition for motion inactive to turn of the fan, delayed 10 mins.

Ah, I used to use a rule just like that. The problem is that the Zooz sensor only reports humidity every three minutes or so. The bathroom would get quite steamy by then. I’m trying to kick the fan into gear sooner to avoid moisture build-up on the walls.

I had trouble with that too. It is fine for some things, but quick reaction to light and humidity isn't one of those.

The best reaction time was actually an Xiaomi/Aqara (square, not round) humidity sensor of all the ones I have tested. You have an extra sensor to deal with, but the speed was well worth it. I can turn on the hot water in the sink and make the fan come on 30 seconds later. The Xiaomi have their quirks though.

The Iris V3 motion seem to be far better than the Zooz for humidity, but I still thought that they were a bit laggy.

I would look at one of the bathroom fan humidity apps. I use Smart Humidity Fan, but there is a couple others.

Also, there was a good tip from csteele about using tape to narrow the sensor beam. I use either a short stub of PVC plumbing pipe, or for a more clean look a plastic "EMT conduit bushing" that is a very thin and nearly perfect size that is intended to keep wires from rubbing on metal conduit. I just hot glue them in place. They come in various sizes, but be careful about electrical stuff not being actual (measured) diameter. These 1/2 are what I used for an Iris V3.

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Good call on the Aqara. Wish they were Z-Wave but I’ll probably buy a few anyway. They are pretty inexpensive as far as sensors go and they are quite small from what I hear.

I’ll get an Aqara and play around with one of the bathroom fan apps.

Thank you to everyone that contributed their ideas.

I am using a solution that @ sidjohn1 posted here: Shower idea.

I am using it in all my bathrooms and it seems to work well. The sensor is sensitive enough to detect water flow and start the exhaust and shower light right away. To reduce false alarms I placed a restriction so that it would only activate if the vanity lights are on. However I do get a few false for example if my son is in his bathroom but not using the shower and Roomba comes along and hits the wall of the shower head it will activate the fan. I really need to change my rule so that is if acceleration is detected for 15 seconds or more than turn on the exhaust, but I still need to figure out how to do that in RM. Rule in Simple Automation right now. Anyway hope it helps. -Pat

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