Request: rain sensor

[scheich]

Hi,

what about implementing an rain sensor? I found this "YL-38 FC-37":

http://www.ebay.com/itm/Regensensor-Feuchtigkeit-Spritzwasser-YL-38-FC-37-fur-Arduino-Raspberry-Pi-DIY-/181797903638?hash=item2a53ffdd16:g:ZmYAAOSwuTxWCq20

Would be nice to report raining to own server and trigger a kind of alert(e.g. email): perhaps very helpful, if you dry your clothes outside. :-)

greetz scheich

edit: or this one? http://cactus.io/hookups/weather/rain/hydreon/hookup-arduino-to-hydreon-rg-11-rain-sensor

[dokape]

Nice. But what does it messure? Liter/square-meter? Or just: light wet, wet, very wet? We have the measure of humidity with several sensors.

[Adorfer]

both are just "raining yes/no"-sensors.

the YL38FC37 is working based on electrical resistance. the RG11 works on optical effects on the sensor surface.

both are unsuited for detecting volume of rain. both are heavily dependend on surface-structure. Any dirt (algues, bird feeces, spider webs) will have heavy influence and potentially delay reactions of sensors (especially "at the end of rain", if the dirt behaves like a sponge.... So at least bi-monthly cleaning is highly recommended.

it's not that volumetric sensors do not need regular cleaning, but there it makes at least sense to go into the effort.

a cheap solution might be to hack into something like

[scheich]

what is used in cars, optical one? think we can close this request :) thx for your explanations

[Adorfer]

cars use the optical approach. And by this you may estimate how unreliable this still is if you have the budget of big companies behind you, And there it's not about the volume of rainfall, but about the simple decision "optical distortion level reached, start the vipers" and "not distoreded any more, stop vipers".

[dadosch]

There is already quite a cheap optical solution with a acceptable (but still not as precise as tip bucket solutions) available called "RG-11".

[Adorfer]

@scheich you were actually right with your suggestion of Hydreon RG-11. It seems to do -from what i gathered now- a rather decent job in "bucket mode", counting individual rain drops in number an size. And cleaning is -compared to bucket-dipping devices- rather easy to do and in plus less frequently needed.

(the reference i looked up were setups for thershold based switching of irrigation systems with simple "on/off relay" as the only output, not real weather monitoring systems.)

The issue i have with the RG11 is: Where to get one?

http://shop.weatherstations.co.uk/hydreon-rg-11-optical-rain-sensor-800-p.asp states a price of around 100€, which looks rather advanced for me, or at least taking into acount my ambition in fitting this to sensor-boxes which are currently not "free from all sides", meaning that some building behind is shielding them, rendering the output rather tainted, depending on the direction and strength of wind.

[scheich]

yes, thats expensive. On http://rainsensors.com it would be 60$ + shipping/tax.

[Adorfer]

On http://rainsensors.com it would be 60$ + shipping/tax.

30$ shipping, and due to the offered transport most likely unavoidable import tax (19%), and with a bit of luck no customs fees (unless you fall into the famous EMS/GdSK pithole) So a bit of a gamble to perhaps save 10€ or pay even 30€ more.

[scheich]

yes, uk store is the better choice and probably the faster one too

[jmberg]

FWIW, I started doing some work on a simple one:

https://github.com/opendata-stuttgart/sensors-software/pull/357

(edit: includes a link to a sensor to buy at ~$16)

edit2: but this is a sensor that reports how much rain actually fell, rather than immediately alerting on rainfall (it'll only trigger the first pulse after 0.3mm of rain), so it's not what the OP wanted

[lichtteil]

What happened to this topic? @scheich how did you solve this? I would also like to detect rain (most important when it starts to rain) by using a 50 cent PCB that just goes from LOW to HIGH when there are water drops on the surface. I have no idea what is the best way to integrate it with the sensor firmware. Do I need to code it myself?

[ricki-z]

We won't implement this in this firmware. We try to measure air pollution. For a weather station there may be better projects than this. (The memory of the NodeMCU is very limited. Thats why we try to focus on our main topic) So yes, you need to code this yourself if you want to use a rain sensor with the same device.

[lichtteil]

@ricki-z don't worry, I fully understand that :) I thought that @scheich maybe found a good solution I guess you can close the Issue then