Question

Has anyone made a homemade rain sensor with a rain sensor pad tied into a smart things moisture sensor? I think it would be cool to have Alexa announce when it started to rain, though would have to turn it off some how so it wouldn’t go off I. The middle of the night. Right now I have dog beds outside drying and it might rain this afternoon so I keep watching the windows like a hawk.  

Answer 1

Could just put a water/leak sensor outside when you want notices like now with something drying outside. ‍♂️. The Samsung ones have water sensors on the top and bottom of the device. That’s my down and dirty simple easy $20 idea

Comments

@avitzur haha. Yeah that’s a pretty good and simple idea. Would rain getting in the sensor short it out? Like if it started pouring?  

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@apprehensible ‍♂️ it’s a $20 sensor - I’d say worth the try and if it does it’s only $20  

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@avitzur Rain water is pure and doesn’t conduct. Few moisture sensors will detect it and if they do they will have a long delay before enough water falls to trigger it.  

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@variola0 what? Please explain. The Samsung sensor has two contacts on the top and bottom of the sensor. When water connects the two sensors (top or bottom) it triggers. So the “amount” of water shouldn’t make a difference, once water connects both sensors it should trigger. So your telling me if I fill a cup with rain water and shove voltage in it it won’t conduct? Also then, how have my irrigation systems worked? They had almost the same basic sensor and if it’s raining it doesn’t turn on. I don’t know that I trust what your saying as “accurate” so I’d like additional info

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@avitzur Depends on how the sensor works but pure water does not conduct electricity. The impurities in water cause it to conduct electricity. Rain water is very pure. Rain falls as spots. You need many spots to bridge across two sensor probes, hence a long delay in detecting rain this way.  

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@avitzur Better to measure soil moisture level for smart irrigation. I developed my own sensors for this   
https://smartisant.com/research/sen...l.php

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Rain water is Def not pure. It will conduct

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@avitzur this sounds like a really cool idea. I want this too and have a bulb turn blue when it ls about to rain and darker blue when it's raining.  

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@balk It will in a polluted environment, like a city. In a clean one it is definitely pure and non-conductive. Rain water that has run off a roof will be full of stuff that has collected on the roof over time.  

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@variola0 rain needs dust particles to form. They condensate around them. More condensate than the weight of natural air current make rain. Only way to get pure water is distillation.  

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To have perfect rain would be nearly impossible. Dust from the country or pollution from the city. Perhaps in the middle of the pacific the dust particles would be so minimal that it could be neglected - even the pollution in LA is from China so there's that.  

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@balk Yes but it’s not black or white. It’s a grey scale. Relatively, rain water is very pure. Not 100% but very close in a clean environment. I tried using moisture sensors to detect rainwater harvesting into a tank. Initially they detected water running but once the crud had washed through and off the roof, the sensors stopped detecting. I developed my own moisture/flood sensor and it’s very sensitive but won’t work with distilled water or ‘clean’ rain water. It just doesn’t conduct well enough.  

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@variola0 sure you need higher volts and a small leak sensor won't provide that. You could get a wireless tank level to detect changes.  

Answer 2

My velux has such a sensor but no idea how to get the info. By the way if someone knows look forward to know how  

Answer 3

My smart home does this. You have to be careful as it could get very annoying very quickly. It only announces it if it hasn’t rained for 24 hours but I get notifications otherwise. I tried loads of sensors and found optical one works best.  
https://smartisant.com/research/sen...n.php

Comments

@variola0 is it possible to tie that into something to get notifications, like a smart things sensor?  

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@apprehensible It’s 12V dc with switched output. It could be done using relay or opto-coupler.  

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Rob, do you have an Arduino sketch for the Hydreon - I don't particularly want to re-invent a wheel :-)

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In terms of Arduino code, it will simply pull the input pin high or low using the on-board relay. Depends on if you use normal-low or normal-high input. Email/messenger me if you need more specific help or sample code. The biggest challenge is going to be interfacing to your particular smart home control system.  

Answer 4

I use Dark Skies app, so not an automation. It notifies your cell right before any precipitation including rain, snow, sleet. Always accurate, but again not a smart appliance.  

Comments

@lona639 that could work. I’ll check it out, thanks