Rain Sensor Suggestions?

[blafarm]

I live in a windy place where rain -- and open windows -- are a bad combination.
I've been looking for a rain sensor to connect to a M1Gold so that a verbal announcement can be made throughout the house.
Anyone know of such a unit? ...especially one that does not require any intervention between fault conditions?

Thanks

 

[rfdesq]

A couple of ideas come to mind:

1. Full blown weather station, I use a Davis 6163. Take the output from the data logger for rainfall. It will require a minimum of .01 of an inch to measure.
2. Soil moisture sensor. It swells when it gets wet and closes a switch. It will stay violated until the media drys out.
3. Home brew rain collector with a GRI water sensor in the bottom. Again, you'll need a way to empty the water and let the switch dry.

 

[mustangcoupe]

2. Soil moisture sensor. It swells when it gets wet and closes a switch. It will stay violated until the media drys out.

A rain sensor for irrigation systems work just like this it swells when it gets wet, and once it dryes it shrinks... triggering a switch..... connect it to a zone input and you are golden.

 

[blafarm]

Thanks for those suggestions. I had looked at those types of sensors before.

Unfortunately, those devices seem to trigger at approximately 1/8" or greater -- and I need to know if it is raining immediately.

We frequently have torrential rain storms accompanied by very high winds -- if windows are left open, walls and floors won't last long.

As mentioned, I could go with a home-brewed GRI-based solution -- but then I'd have to "empty" it several times each week (if not each day).

I suppose what I am looking for may not exist -- but I'm open to suggestions.

Thanks


EDIT:

I just searched for "instant shut-off" irrigation sensors -- and there might be something here for me to investigate further

 

[BraveSirRobbin]

http://www.hobby-boards.com/catalog/produc...roducts_id=1544

 

[politics123]

Is there a reason an at-home occupant wouldn't notice it raining, or wouldn't hear the thunder?

The challenge here is translating the "analog" decision that its raining into a digital world. You know its raining by a combination of three senses:
1) You might feel pressure on your arm/head/back as a raindrop hits it
2) You might see a raindrop fall
3) You might here some noise, and in combination with 1 + 2, decide its raining.

Alternatively, you might see a weather report that calls for rain, or you might look at weather radar and see that its "green" over your house.

I don't think irrigation timers meet your definition. "Instant" shutoff for irrigation (note: still takes 2-5 minutes)
http://www.hunterindustries.com/Products/S...nclikspecs.html

How about something decidedly different:
-- a sensitive microphone installed on/near/under something metalic that's located outside.

When it starts to rain, the "noise" of the raindrops is picked up from the microphone and amped throughout the house. Alas, you might pick up the errant bird Perhaps a humidity sensor tied to a relay would reduce errant noises. If you have enough money, you might research an extremely sensitive pressure plate as well.

Alternatively:
1) you can install a few LCD screens around the house that show local weather radar. You can even use an image diff routine to determine if the radar has painted a "green" picture near your house.
2) you can automate off of the prediction of rain (eg: weather forecast automation)

My opinion on the most reliable sensor??
Get a dog that's afraid of rain.

 

[blafarm]

Thanks for your replies.

I may have stumbled onto something that might solve my problem -- although it will take a bit more research and a fair amount of hacking;

http://auto.howstuffworks.com/wiper4.htm
http://www.oedes.com/raintracker.php
http://www.sriraaga.com/rainsensor.html
http://www.trw.com/images/rain_sensor.pdf

 

[Photon]

How 'bout a WaterBug sensor?

http://www.automatedoutlet.com/product.php...at=0&page=1

 

[blafarm]

That's kinda where I started.

A WaterBug or GRI Water Sensor sitting in a very small container. However, that led to concerns about how much time it would take to accumulate enough water in the container to trigger the device. I was also put-off by the necessity of having to empty the container every time it rained so that the apparatus would be ready for the next incident (which I would consider an unacceptable amount of administration).

I considered an inverted WaterBug installation with the contacts facing up -- but I again became a bit concerned about the amount of rain that would need to fall on the sensor to trigger the device -- and I was unsure of how long that moisture would take to evaporate to be ready for the next incident. I also considered mounting the device at an angle, so that water hitting the sensor would be encouraged to drip off the side thereby decreasing the reset interval, but I was concerned that an angular mount and dynamic dripping might work at cross-purposes to my goal of immediate sensing.

This approach might still be the simplest and least costly initial solution -- but automotive rain sensors offer some unique advantages which I will need to research further.

 

[BraveSirRobbin]

blafarm:

PM me your mailing address and I'll send you one of those Hobby Board's rain sensors. I believe they will work out for you, especially if you mount them at a slight angle off horizontal.

 

[RAM]

blafarm:

PM me your mailing address and I'll send you one of those Hobby Board's rain sensors. I believe they will work out for you, especially if you mount them at a slight angle off horizontal.

I think these work on the same principle as the rain sensors on my Anderson skylights. If they work anywhere as good as they should be fine. The Anderson sensors shut down my skylights (powered cranks) at the first hint of rain. A few drops will have my skylights closing. Sometimes even a heavy dew in the morning closes the skylights.

 

[blafarm]

Thank you BSR for that very generous offer.

And, hope you're right Rich. It would be great if it went that smoothly.

 

[bhlonewolf]

Not sure this is overly helpful, but I was in a similar situation where I wanted to monitor a few things -- rainfall, temperature, humidity, windspeed... that kind of thing. One of the uses was exactly what you had in mind, but also for irrigation (more/less water based on conditions), inside vents based on temp/humidity, warn me if the temp goes below freezing, etc.

I happen to have a computer on 24/7, so what I've done is written an application that pulls the data from the web and just keeps it stored in an access database. I live about 10 miles from the nearest airport, so I pull the data from that airport's feed. There are a few weather stations that are a tad closer, but for whatever reason I feel more confident in the airport's data. Is it 100% accurate? No. Is it close enough? Yep. 90% of the time, it's advanced notice by a few minutes due to typical weather patterns, but of course, it's a polling technique so there's some delay.

I'm not a meteorologist, but you may be able to do something like this by monitoring dew pt and humidity changes to guess when it will rain. I'd imagine that even with a rain sensor, by the time it collects enough to trigger, you'd probably be aware that it's raining.

I then feed the data back into PowerHome that can then run fans or alter the irrigation as necessary. (At least, in theory, I haven't done the irrigation stuff yet )

 

[blafarm]

Thanks for that.

Unfortunately, I live in a place where there can be close to an inch of rain at my house -- and no rain whatsoever 5 miles away. Also, if one is in a soundproof bat cave theater -- there is simply no way to know if it is raining outside...and that can be for 2 hours or more.

I'm looking forward to being able to test BSR's potential solution.