Looking for some ideas for snow and rain sensor

Guido

Glad to have this forum. There are many talented individuals here and when I ever have a problem I know where to go.....!!

Here is the problem. I have a remote outdoor camera at a remote location. It has a windshield wiper assembly and I want to control the motor when it snows or rains. The location gets about 7 feet of snow in the winter and the average temperature is below freezing. The camera housing does have a heater, but I know that if it snows it will eventually freeze on the glass, and it would be impossible to thaw or move with the wiper. I have thought about a photocell-light detector, but I think the snow would eventually make it usless as well.
Any ideas would be greatly appreciated.
Thank You
Guido

Yanroy

How about a photo sensor that looks out the same opening as the camera (or maybe more than one).· Every certain amount of time (like 15 minutes or somesuch), run the wiper.· If the reading from the sensor after wiping is brighter than the reading before wiping, you know there was something on the window.· Then you can run the wiper at a faster pace for a while, then slow down and repeat the above procedure to see if stuff is still accumulating on the glass.

I have another thought as well... an IR beam (perhaps even a laser) that goes across the front of the window so that anything on the glass will cause the beam to be broken.

I hope one of those at least sparks a thought that will help you.

pjv

Hi Guido;

So what is the (photocell) detector for? Is it to prevent the (frozen) wiper from moving? Or to confirm the wiping has occurred? Or that it's been snowing and to take a picture?

I don't understand your problem.

Cheers,

Peter (pjv)

Robert Kubichek

Guido said...
Glad to have this forum. There are many talented individuals here and when I ever have a problem I know where to go.....!!


Here is the problem. I have a remote outdoor camera at a remote location. It has a windshield wiper assembly and I want to control the motor when it snows or rains. The location gets about 7 feet of snow in the winter and the average temperature is below freezing. The camera housing does have a heater, but I know that if it snows it will eventually freeze on the glass, and it would be impossible to thaw or move with the wiper. I have thought about a photocell-light detector, but I think the snow would eventually make it usless as well.

Any ideas would be greatly appreciated.

Thank You

Guido

Well, I would add a hood to keep rain/snow from hitting glass, as this would reduce a lot of the problem.


Bob N9LVU

Paul Baker

Robert Kubichek said...

Well, I would add a hood to keep rain/snow from hitting glass, as this would reduce a lot of the problem.


Bob N9LVU

Do you live in an area where it snows quite a bit? Snow is notorious for falling sideways given enough wind, when I first moved to Virginia I spent hours looking out my window during the first major snow storm (24", enough to shut down DC metro for 3 days) watching the snow float down, sideways AND upwards, all at the same time depending where I looked, being a Florida boy I was unable to stop watching until my eyes grew tired.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·1+1=10

kelvin james

I am assuming the glass you are refering to is a pane of glass protecting the front of the camera, and not the lense itself. There is a product that parallax sells called the QT113 touch sensor, which can use a plate of glass as a proximity sensor. In theory, water or ice forming on the glass would be sensed, and used to output a signal to a wiper or internal heater. Since i have never used one of these before, i can't say it will work, but it might be worth taking a look at.


www.parallax.com/detail.asp?product_id=604-00038

kelvin

Guido

Thank You All for your help..
Kevin, I think you have a great idea, I am going to have to give it a try when they come back in stock. This way everything stays in side the camera housing for protection..Thank You All again!
Guido

kelvin james

Hi, upon further reading, it looks like it should work. The sensing electrode could just be bonded to a small area near the bottom of the inside of the pane. There are lots of configuration settings to use to be able to get the type of operational parameters that would be useful for moisture activation. Also, you may want to look at a contact tempature sensor for the glass, to give more control over the hardware, depending on certain weather elements. But always a downside, you will want the version that is good to -40, unfortunately, it only comes in a SOIC, and you would have to order that from digikey. I guess there are other means to accomplish this kind of operation using different kinds of sensors, but the QT113 is pretty cheap, so no big loss if it doesn't do what you want. I included a link to qprox, and look at the pdf "touch secrets". There is some good info on the water film issue.

[url=http:// http://www.qprox.com/toolbox/index.php?submitted=1&partNo=QT113-D] http://www.qprox.com/toolbox/index.php?submitted=1&partNo=QT113-D[/url]

kelvin

Danny

My experience with snow sensors (for driveway melt systems) is that they have a thermostat, heater element, and moisture sensor.
When the temp gets to 38 degrees fahrenheit, the heater element comes on, then any snow that falls on the sensor (think of a small funnel here) melts and runs onto the moisture sensor. The moisture sensor then give me a signal that I can reliably interpret as being from snow. Since it is only active when the temp is below 38. Pretty simple and reliable, lasts for years. Google snow melting systems for more details.
Danny

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"Never create anything you can't control"
"The amount of intelligence on the planet is fixed... the population is growing"

steve_b

You could use a simple laser shining from the inside of the enclosure (pointed at the glass).
When contaminants cover the glass, more light will be reflected back in to the enclosure...this is where you could have a photocell of some sort picking it up.

We use this method on some of our laser ceilometers. Birds like to hang their rear-ends over the lens and black our measuring beam.

As far as determining snow from rain...just use a temp sensor....there's the obvious gray zone from -5degC to +5degC of whether it's snow/rain/frozen precip.
You could also use a contact sensor...basically it looks like a bare circuit board with traces going back and forth. When precip hits this board it shorts out and gives a resistance OTHER than Infinite (open)....and you could heat this board for snow too (just use a little 5W resistor underneath with some power going thru it--that's all those Pelco camera boxes do).

IF you want to get real fancy....purchase a surplus police radar gun. Aim it up and measure the speed of falling precip. This, along with a temp sensor, will let you determine the type of precip falling (snow falls slower than rain...but false calls are made with frozen rain and hail and such). This is a fun way to do it...but certainly overkill.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·

Steve

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."