Author Topic: Economy Radiation Shield (Read 26332 times)

DanS · « **on:** March 14, 2009, 02:03:44 AM »

I recently constructed a stacked bowl type of radiation shield to experiment with and found some interesting results in the tests.
The construction and materials are pretty much the usual or standard stuff. However, I wanted to make sure that the bowls overlapped enough so no outside area was visible confirmed by looking down through with the top bowl off. The top and the bottom bowls are the only two not cut out.

The interesting results now. 1st chart shows 3 days temp readings of a standard WS-2310 with it's "hat" on located in the shade with only the ground below lit by the sun. The sun keeps the ground lit until around noon where it is then blocked by my house for the rest of the day. The peaks on the charts show the sunshine until the house blocks it. The 2nd chart is two days with the "hat" removed and the shield on the sensor.

Measurements in the same location and all clear sunny days. The sensor "sees" the sun's radiation on the ground almost like a photocell.
Oh, total cost of the bowl shield came to $2.80. I like it better than the WS-2310's supplied weather "hat".
I hope this helps anyone thinking of building one in the future.
Dan

edit: Since the time of this project I've learned that this type of thermo/hygro sensor uses a thermistor type temp sensor which is sensitive to sunlight. Most wx stations today use a temp/hygro combination chip that is not sensitive to sunlight so this isn't an issue.

SlowModem · « **Reply #1 on:** March 14, 2009, 02:39:06 AM »

That's pretty neat! I'll have to give that some thought and see if I can sneak some bowls out of the kitchen!

DanS · « **Reply #2 on:** March 14, 2009, 02:45:49 AM »

Better not let momma catch you though. She might hang you up outside to use as a wind sock.

SlowModem · « **Reply #3 on:** March 14, 2009, 03:57:39 AM »

Quote from: DanS on March 14, 2009, 02:45:49 AM

Better not let momma catch you though. She might hang you up outside to use as a wind sock.

With my build, I'd look more like a wind ribbon than a wind sock! ROFL

SlowModem · « **Reply #4 on:** March 18, 2009, 11:15:02 AM »

So what did you use to cut the bottoms of the bowls out? Knife? Saw? Hot iron? They look perfectly punched out.

SlowModem · « **Reply #5 on:** March 18, 2009, 06:32:52 PM »

Well, I had a bunch of little white bowls (made in Thailand by the way!) ready to go under the knife. I don't have any double sided tape. I was leaving to go to the dollar store when I saw an old, plastic flower pot. Hmmmmm

This has one big hole in the bottom and lots of little holes in the top (depending on which way you hold it). That would allow for air circulation while shading the sensor (well, it should allow me to see if the helmet is restricting the accuracy of the sensor, and it does get 10 degrees hotter than the OS unit when the sun shines on it). So, flower pot and wire ties in hand, I headed to the weather pole. It should be interesting to see if there's a difference in readings in the morning. (with my luck, it'll be cloudy and rainy and won't make a difference). Anyways, I'll keep you posted on the results.

Greg

PS: Yeah, I know it's green and not white.

DanS · « **Reply #6 on:** March 18, 2009, 07:07:59 PM »

Hi Greg. Your dark pot will give you slightly higher readings due to the absortion of heat, white reflects better. I don't know about Davis and OS sensor sensitivity to heat but I do know the WS-2300 sensors react to any sunlight "seen" by the sensor, reflected up from the ground and nearby objects as well. So the inverted pot will help keep the direct sun from above off of it but the bottom is still exposed and the small drain holes up top let in light. If you use WUHU and set it's temp graph to zoom in so it's updating by the minute you can see what I'm talking about by watching it as you block sunlight around the sensor's area. They're really sensitive! This is the reason I'm experimenting with using deep dish bowls for a shield. They block any sunlight, direct and indirect/reflected, and still allow air. You can understand this better also by checking out professional stevenson screens and why they use double louvered walls. I'm also currently experimenting with different solar panels and fans for aspiration to see how that effects response times of the readings. Between all of us forum'ers conducting all these tests somebody's sure to find a happy result.

Cheers,
Dan

WeatherBeacon · « **Reply #7 on:** March 18, 2009, 09:57:57 PM »

Oh. And here I thought you meant shielding ourselves from the current economic meltdown.

DanS · « **Reply #8 on:** March 18, 2009, 10:03:38 PM »

Boy I wish I did have a solution for that! That problem makes you "clock hands alignment" problem child's play.

WeatherBeacon · « **Reply #9 on:** March 18, 2009, 10:06:34 PM »

Quote from: DanS on March 14, 2009, 02:03:44 AM

Measurements in the same location and all clear sunny days. The sensor "sees" the sun's radiation on the ground almost like a photocell.
Oh, total cost of the bowl shield came to $2.80. I like it better than the WS-2310's supplied weather "hat".
I hope this helps anyone thinking of building one in the future.
Dan

Interesting plots, Dan. Puts it in perspective. Nice design!

DanS · « **Reply #10 on:** March 18, 2009, 10:12:28 PM »

Thanks Kevin. The construction is just temporary to see what happens. Later I'll make something a little more solid from the results of all the experiments. I'm stiil going to add a small fan and solar panel for aspiration.
Anyway I'm seeing results to confirm my suspicions.

Cheers,

Dan

SlowModem · « **Reply #11 on:** March 19, 2009, 07:46:29 AM »

Quote from: WeatherBeacon on March 18, 2009, 09:57:57 PM

Oh. And here I thought you meant shielding ourselves from the current economic meltdown.

DanS · « **Reply #12 on:** March 19, 2009, 08:28:50 AM »

Got some news to add about shields and solar fans. I added a panel and a fan today but haven't had a chance to see results yet. Some pics,

The panel is from an old broken solar lamp (see pic) and the fan came out of one of those novelty solar caps. The panel produces around 3.2V in full sun with the fan connected. I've also learned that computer fans made to run on 5v won't work with these kind of small panels. Just not enough power from them. The little hand held personal fans will work because those motors run off 2 AA (3V). When I get a couple of sunny days I'll compare old and new readings and post 'em.

Dan

SlowModem · « **Reply #13 on:** March 19, 2009, 08:33:30 AM »

Dan,

You should have worked for the Patent Office or something!

Greg

sam2004gp · « **Reply #14 on:** March 19, 2009, 09:04:36 AM »

Hmmm, Dan gave me some more ideas for my search for a cheap solar solution. Time to find a solar landscape light on clearance at my local hardware store.

DanS · « **Reply #15 on:** March 19, 2009, 09:22:33 AM »

Great Sam. The one I used was a wall mart clearance item. Something like a pack of 6(?) for around $20 or so. That was years ago and I know you can buy them in single packs real cheap. Just be sure you find one with the biggest panel you can can get and not one of those types with a bunch of little panels lined up around the rim. You posted a picture of a computer fan you already have. It will not work with a solar light's panel. That fan is 12v, way to high for this type of panel. I was hoping the little 5v computer fan would work and bought a couple to try. Nope, no go. Now I have spare mini 5v computer fans for the next project if I need 'em. I also bought a couple of those little hand held personal fans and busted one open for it's motor. It worked o.k. but I didn't like the little soft flexible "safety" blade on it. Then I saw on the internet those solar fan baseball caps and remembered that I had one somewhere. Located it, dissected it, installed it, and it all works.

Let us know if you do decide to do this and there will be loads of help.

Dan

Bushman · « **Reply #16 on:** March 19, 2009, 09:33:09 AM »

DAn, regular PC fans are 12v while video card fans are 5v. They work at lower voltages and should work with your panel. You can literally get them for a couple of bucks brand new.

DanS · « **Reply #17 on:** March 19, 2009, 09:54:37 AM »

Bushman,
I understand what you're saying about the different fans. The 5v computer fans are also used with USB driven computer accy's. because of the USB power available. I have several electronic shops nearby that carry them for about $1.20 a piece so I got a few to try with these little panels. The panels I tried don't have enough current capability to drive these 5v motors. The little 3v fans I talked about work though. I can't find any specifications written on either the motors or the panels but believe the fan draws just about the maximum the panel can provide. Also both the panels and fans come from 2 AA (3v) battery devices.
You can still try though. Maybe you can find a more efficient panel. Mine is ancient. Good luck and keep us info'd on your progress.

Dan

SlowModem · « **Reply #18 on:** March 19, 2009, 09:58:22 AM »

Quote from: DanS on March 19, 2009, 09:54:37 AM

Bushman,
I understand what you're saying about the different fans. The 5v computer fans are also used with USB driven computer accy's. because of the USB power available. I have several electronic shops nearby that carry them for about $1.20 a piece so I got a few to try with these little panels. The panels I tried don't have enough current capability to drive 5v motors. The little 3v fans I talked about work though. I can't find any specifications written on either the motors or the panels but believe the fan draws just about the maximum the panel can provide. Also both the panels and fans come from 2 AA (3v) battery devices.
You can still try though. Maybe you can find a more efficient panel. Mine is ancient. Good luck and keep us info'd on your progress.

Dan

If I remember right, you can hook two or more panels in series to increase the voltage, or in parallel to increase the amperage.

I over E except after C? ::::looking at left hand for a rule::::

Greg

SlowModem · « **Reply #19 on:** March 19, 2009, 10:02:04 AM »

Oh, speaking of flower pots.....

I have been monitoring the temperature difference between the 2315 (now in the inverted flower pot) and the 968. Yesterday the difference got up to 10 degrees. Today, the difference has only gotten to 5 degrees.

So......

In a few minutes I'm going to go outside and place the 2315 in the good (store-bought) shield and try to make a bowl shield for the 968 sensor (actually a THGR122NX).

More news as it develops.

Greg

DanS · « **Reply #20 on:** March 19, 2009, 10:03:08 AM »

You remembered correctly. 2 in par. to double the current or 2 in ser. to double the voltage but I don't want a bunch of panels all over my dinky little shield covering it up so the "neighbours" can't see it.

mackbig · « **Reply #21 on:** March 19, 2009, 10:24:18 AM »

I was going to try and use my old solar xmitter with battery from stock thgr968. but I think it only puts out 3 volts with low amperage.....

However now I have decided to go this route.

Buy a clearance 12 volt low volatge lighting system. use a 12 volt pc fan. I doulbt it will draw much wattage. then next fall i will hook up my rain gauge heater to that as well. then I will only be running the fan and one light bulb next winter..... as it was I ended up running my entire landscape lighting system 24 hours a day from November to last week. At a couple of hundred watts, that wasted a bunch of electricity per day... not to mention I probably shortened my bulb life tremendously for the other lights that were typically only on dusk to 11pm prior to that.

Andrew

sam2004gp · « **Reply #22 on:** March 19, 2009, 10:36:18 AM »

mackbig, I thought about doing the same thing you mention, but my Temp Sensor/Fan/rain heater locations are a good 75 feet apart from one another, and I would have to run a wire under a sidewalk.

SlowModem · « **Reply #23 on:** March 19, 2009, 11:02:46 AM »

Well, when all else fails, tear it apart.

The more I looked at my setup, the more I thought I could get chocolate in my peanut butter. So I took the radiation shield apart, took the "stick" out of it that the sensor was attached to, crammed both the OS and LaCrosse sensors up into the shield, put a solid bottom piece on it and it is done. You can see bits of this process on my web cam: http://www.wunderground.com/webcams/Slowmodem/1/video.html?month=03&year=2009&filename=current.flv

The sensors are touching the sides of the shield in places. This will probably affect it somewhat. However, it's supposed to be made of low-heat-conductivity material, so I think the shade effect will be much more than the conductive effect. We'll see.

Of course, placing a fan on top will require a complete disassembly again. But I'm getting good at it!
No disassemble! No disassemble!

mackbig · « **Reply #24 on:** March 19, 2009, 11:03:41 AM »

Both of mine are in backyard relatively close along the same run between the border fence and interior privacy lattice fence.

Hmmm, just had an idea, I could acquire one of those highway sized solar panels mentioned earlier (6 feet by 6 feet), angle it towards the sun, but out of my "view", my neighbour who had conerncs about my little white radiation shield would get a kick out of that... I could get some of those fallout shelter signs too.

Andrew

Quote from: sam2004gp on March 19, 2009, 10:36:18 AM

mackbig, I thought about doing the same thing you mention, but my Temp Sensor/Fan/rain heater locations are a good 75 feet apart from one another, and I would have to run a wire under a sidewalk.

News:

Author Topic: Economy Radiation Shield (Read 26332 times)