Bathroom motion sensor (Glassdoor issue)


I have the expected PIR motion detector issue while standing in my shower (It does not recognize me).
Already tested it using a hue and a homematic sensor. I had one in the shower cabin but I think this is not very healthy for the hardware.

So I would be happy if there is someone experienced in different motion sensors.

Is there some hardware solution available which is working through glass? It should be tasmota, esphome, hue or homematic compatible. I don’t want to add another hub. :slight_smile:

Or is there another smart thing recommended which will detect me while I am inside my shower?

Radar / microwave based motion sensors.

Do you have a concrete vendor / hardware which you would recommend?

Humidity/temperature? Or is it a “sealed” shower?

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Are you ok with a DIY approach, or do you prefer a commercial off the shelf product ?

It is a non-sealed shower. Maybe that’s an option.

Would be better if there is an of the shelf product - I am not that good in soldering anymore :slight_smile:

Yoy could get a ESP with pins soldered and just hook it up with dupont wires.

No soldering needed :grin: I don’t have too much experience with off the shelf solutions, but there are lots available on Amazon / ebay etc. Search for microwave motion sensor. If you want to make it wireless, you will typically need an existing sensor (Wifi/Zigbee/Zwave/whatever) with a dry contact entry. I do have (excellent) experience with the Bosch BDL2-WP12 series, but they use a combination of PIR and radar. I’m not sure you can disable to PIR part, so they won’t really help much in your case.

If you want to attempt DIY, this is a great video here.

Alternative: PIR sensor + silicone caulk to make it water proof. Changing batteries will be a PITA.

Alternative 2, a little more intrusive: water flow meter on the shower water supply.

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Presuming that you close the bathroom door whilst showering, a far simpler method is to accompany your motion sensor with a door sensor and operate the ‘wasp in a box’ principle.

If the door is closed and subsequently motion is detected, then the room must remain occupied until the door is opened again, regardless of whether further motion is detected.


Only works if the door is always closed when you shower, not randomly opened and closed again by your significant other while you shower and your door is closed when you finished showering. Lots of potential failure modes that reduces WAF (or GFAF in my case :slightly_smiling_face:)

Microwave is actually not great at penetrating glass, so that’s probably out. I have a PIR sensor attached to the ceiling at about 8-10’ (depending on the shower), right above the shower. It performs perfectly.

Actually longer wavelength MW around 3-6 GHz is perfect at penetrating glass. The 24GHz ones will suffer a little attenuation, but will still work well. I have several MW sensors operating through glass (even double pane insulated), there is no notable attenuation.

Color me surprised. I’ve seen testing suggesting otherwise.

Replace the girlfriend is the answer to that one. Anyone who fails to respect the basic privacy of bathroom time needs returning for a refund :wink:

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Physics suggest otherwise :slightly_smiling_face: Of course in the end it depends on the type of glass. Some types of thermal / IR reflecting glass have extremely thin metal coating, this will indeed kill the signal. Usually you won’t find this type of glass in a shower though.

Hahaha yeah :grin: I’m afraid that won’t be an option, the return window is already closed :smirk:

But your system works really well if you live alone.

I live in a home with 6 others; partner and 5 children. Bathroom doors have bolts for a reason, people wandering in and out of the bathroom whilst it’s in use is just weird.

Depends on the household I guess. If the constraints on the door are respected, then the wasp in a box system works pretty well.

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Why don’t use water metering - if water flows, somebody is under the shower :slight_smile: