How Do I build a Cloudiness Sensor?

General Chatter
1

I bought a Davis Solar Radiation sensor to build a cloudiness sensor. I had found a link on the Web that gave me some rudimentary information but now I have lost it. Here is what I believe my method could be:

Mount the sensor on a horizontal plate with a vertical plate to the south shielding the sensor. I probably need to find the maximum apex of the summer sun at my latitude to determine how high the plate should be to shield the sensor. I want 100% shielding of from the sun at noon. I also need to know how wide to make the vertical plate to make sure the sun doesn’t shine on it in the morning.

I also need to know what color the shield material should be or does it matter. I plan on using a reed relay that is remotely controlled and timed by my computer to switch between the unshadowed sensor and the shadowed one and read the values accordingly.

Anybody have ideas or direction on how I can go about this?

Thanks,
Paul.

2

what if you lived near the equator and the sun is overhead at noon??

with solar sensor, like davis, you get a fairly good idea of cloudiness by knowing the difference between the max solar radiation at the time of day and for you lat/long and the current reading is…weather display does that for you automaticly, and comes up with a solar %, which it then converts to a cloudiness description, automaticly

3

Well, if I lived at the equator, I would have a drink in my hand, would be laying out on the beach and wouldn’t care what the weather was doing at all!!!

4

weather display calculates the cloudiness from that computed solar % and its available as a custom tag to, so you could have it in a script file, etc, and use with home automatation sotware, etc

5

Why do you want cloudiness anyway? I would have thought that if you wanted to adjust a blind then the the solar value would do it. For example 50% cloudy on June 21st, is a heck of a lot brighter than 50% cloudy on December 21st :?

6

For those of us that live in the northern hemisphere!
Good job the developer doesn’t live in the southern hemisphere… :lol:

7

Touch

8

Windy said:

weather display calculates the cloudiness from that computed solar % and its available as a custom tag to, so you could have it in a script file, etc, and use with home automatation sotware, etc

Where would I get this data?

9

if you used WD, then its all done for you auto (the % cloudiness)
but you are not intending on using wd i gather?

10

I downloaded WD and took a look at it.

11

there are lots and lots of customtags
and via those you can get all the data, into , say a script file, that you can use (i.e you can get wd to create a custom script file, etc)

12

Not to mention the xml output which contains everything you could possibly need.

Julian