Sensors and Snow

[Admin]

whats up with the picture?
all i got from it was a bunch of the navy standing on a ship

The forum auto-shrink image feature broke during the last software upgrade . . . you'll have to use the scroll bar to see the rest of the image for now

[Soeren]

It's only part of the picture - Follow the link, it shows the picture in whole.

[SmAsH]

It's only part of the picture - Follow the link, it shows the picture in whole.

what? what link?

[Admin]

It's only part of the picture - Follow the link, it shows the picture in whole.

what? what link?

Otherwise I like Soerens idea. The Navy does that, covering up radar dishes with bowls. For example, those ball thingies on this ship are covered up dishes:

http://aycu20.webshots.com/image/47099/2003529587801442487_rs.jpg

[kpmcgurk]

Hmmm, Im confused with the picture?

[SmAsH]

admin was showing that the navy cover they're dishes with bowls do
prevent... damage?
i think i get it now, thanks guys.

[kpmcgurk]

I see that actually would be a great way to do it, this would keep the snow off of them in general!!

[SmAsH]

does anyone know if it being closed interferes with the signal quality?

[Soeren]

Hi,

It won't interfere if the material is carefully selected - a metal dome would be a big no-no of course

[HDL_CinC_Dragon]

If it interfered with the signal strength im pretty sure the Navy wouldnt use it Heck im sure if you just Saran wrapped the thing youd be good to go lol

[GearMotion]

If it interfered with the signal strength im pretty sure the Navy wouldnt use it Heck im sure if you just Saran wrapped the thing youd be good to go lol

Or like I suggested on the first page - tarp. I've seen many dishes covered in tarp like a drum skin stretched on a frame. Again - A physical solution to prevent snow accumulation might just be the easiest.

[paulstreats]

back to the original problem.

Roombas have a sensor that detects heavy particulates. meaning that if a lot of crumbs hits a sensor then it concentrates on cleaning that area more.

A similar sensor could detect rain and possibly snow drops hitting it. I would imigine its just a simple piezo type sensor with a program that detects high/fast rise peaks...

[kpmcgurk]

I would see what I could do as far as making something, and then testing it, but unfortunately it is the summer(springish), and there is no snow so I cant

[Asellith]

They make dome tarps designed to do this but they cost around $500 to buy per site. Thats is way out of the budget. The budget for this project is like under $30 because it will cost me about $200 to have the tech install it and ship it. Let alone my time building the device. We just can't justify spending to much money on these sites as some bring in like $1500 a year in contributions and thats barely enough to cover the rent at the site.

[paulstreats]

piezo discs can cost like $1 each...

[HDL_CinC_Dragon]

1) Would the current generated by a piezo being struck by a rain drop be enough to read by a cheaply available MCU?
2) I thought piezos only reacted to the intial change in pressure on their surface so like if you pressed down on one with 5 newtons of force and held it w/ 5N of force for like 10 seconds, wouldnt their only be a current from the time it takes the ~0 newton forces on it to reach 5 newtons(such as a fraction of a second if you were pressing on it with your finger)?

If my second question is indeed correct then that method would be entirely ineffective because you wouldnt be able to tell if there was anything currently on the piezo, you would only be able to tell if something was enacting a force on the piezo at that point in time... and even if you had some sort of memmory for it so that when you woke up in the morning to look at the display it said "something hit the piezo" or w/e think of how annoying that would be every time a large gust of wind came by and pushed on the piezo. If its sensitive enough to detect the force of a rain drop, a moderate gust of wind would surely be able to set the thing off.

[Soeren]

Hi,

As you assume, a piezo only gives a signal when hit (actually, when flexing). The signal looks like a dampened sine, since a hit will vibrate it like that.