I have humidity sensors that turn on the bathroom fans when humidity is elevated, i.e. when someone is taking a shower. I'd also like the fan to be on when someone goes .
Currently, my proxy for this is whenever the bathroom is occupied with the door closed, but certain family members find that irritating. What I'd really like is a sensor that can detect that the bathroom is smelly and trigger the fan on that.
It seems that such sensors exist; I have an air purifier that runs on auto, and it will trigger for smells wafting in, smoke from cooking, etc. But I'm not certain what sensor it uses or how one might be connected to Hubitat.
It would be intersting to know what specific thing the air purifier is using to trigger on. Sounds like you need a tvoc sensor. You could do that with just a esp32 and the sensor.
Ah, but that gets false positives for pee, only triggers when they're done, and requires that both kids remember to flush. At that point, my current "door is closed" trigger is roughly as accurate and fires sooner.
What if you used a pressure sensor on the toilet seat? You could calculate a rough interval that determines the difference between sitting to pee (less than one minute) versus pooping (two minutes or greater). This also has the advantage of letting you know who left the toilet seat up.
The other idea would be to wire something up to the toilet paper roll. Based on how many rotations could tell the fan to turn on. The more rotations, the more likely a poop, the need for the fan.
I tried to make poo sensors to turn on a vent when my cats used the litter box a few years ago. Never could get it to work. Tried 3 or 4 different sensor types.
In that situation I just used a particulate matter sensor, as the litter very reliable made measurable particulates when disturbed.
I know that doesn't help you,, just thought I would share as it is tangentially related.
I don't think bathroom smells would show up on a particle detector. Also, I was considering an IKEA air quality sensor before, but I heard it only updated once an hour, so not really all that useful for me.
If you're talking about VINDSTYRKA, this is not true. In reality, the sensor is chattier than I like and it sends data way too often. Besides temperature, humidity and PM25, it also sends a "VOC index" sensor value (1..500) that works in a very interesting way:
Sensirion claims that it works "like a human nose". I believe that there is real potential for using this as "stinky sensor". I need to find a good position for it in the bathroom and give it a spin
The downside is that it is USB powered; it contains a small intake fan that draws air inside it. Unfortunately, the fan's position (on the back of the device) limits placement options.
For the EU folks, there is also the Swedish Fresh Intellivent Sky. Although it cannot be controlled by Hubitat, it automatically adjusts its fan speed based on humidity and "air quality".
I own the previous model Intellivent 2 and it's been working non-stop (always spinning on low speed) for more than 5 years:
it increases the fan speed based on humidity and it adjusts its humidity threshold automatically
I can easily remove the impeller to clean it (I do this every 2 months or so)
it is really really quiet when it works in its normal/low-speed mode
Oh! How often is often? What I wanted was to see if it could detect when my nasty neighbor is smoking to turn off the window fan, so for that the more frequent the better.
Since I could not figure it out how to configure reporting based on value change (+/- delta), I put a limit of max 1 report/second to filter the events, but I must adjust it further as it is still flooding the logs.
The reports are not that frequent all the time. It goes beserk only when the air quality changes, e.g.: I vape in the room.
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