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3D Printed Radiation Shield for Meteo Stations
#1

3D Printed Radiation Shield for Meteo Stations - Part 1

Overall View

Since long time that I'm thinking in a 3D printed Radiation Shield to replace those I have, with more than five years of use. Recently, I found on Thingiverse a model with a detail which I particularly liked, which is the capability to easily remove the sensor for replacement, or just for the annual inspection.

However, from my past experience with radiation shields, the original design doesn't full fit my requirements, but the idea of being able to easily remove the sensor is so good that I decided to take it as a base, and make some changes:

[Image: RadiationShield_07.jpg]...[Image: RadiationShield_08.jpg]


- Instead of having the plates just on top of the other, they are now overlapped by a distance of 50mm, this reduces the possibility of rain to reach the central part of the radiation shield and damage the sensor.
- The size of the plates was increased to 110mm.
- The size of the central hole was increased to 40mm to accommodate an optional 40mm fan.
- Redesigned the support of the sensor to:
  • Include an optional connector for the fan.
  • Allow using an additional chamber for the sensor (more on this later)

[Image: RadiationShield_04.jpg]...[Image: RadiationShield_12.jpg]

- There are two construction options:
  • Standard Radiation Shield
  • Standard Radiation Shield plus a small (25mm) box integrated on the base, intended to place some electronics when needed, which can be the case of those who are using I2C Extender circuits.

[Image: RadiationShield_01.jpg]...[Image: RadiationShield_10.jpg]


Everything prints fine without supports.
Ideally, for UV protection and additional mechanical resistance, it should be printed using ASA, PETG or ABS.
I printed the first unit in PLA with a resolution of 0.3, and painted each piece with enamel acrylic ink. Blush
Later I plan to print a second unit in PETG which is waterproof, impact resistant and more durable than ABS. Thanks to a strong layer adhesion, it can better withstand UV light and is generally less challenging to print with. Additionally, PETG emits no smelly fumes.

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#2

3D Printed Radiation Shield for Meteo Stations - Part 2

The Parts

After the overall view, we are now going to focus on the elements needed for building our Radiation Shield.

List of the 3D printed parts:
  • The top plate: 1 unit
  • The middle plates: 5 units (if needed can be more)
  • The base to fix the sensor mounting piece: 1 unit
  • The wall (or pipe) mounting piece: 1 unit
  • The sensor mounting piece: 1 unit
  • The sensor protection chamber: 1 unit
  • The box for additional electronics (optional): 1 unit
  • The bottom cover for the optional box: 1 unit

The pictures below show each part by the order they are listed.

[Image: RadiationShield_Elements_01.jpg]...[Image: RadiationShield_Elements_02.jpg]...[Image: RadiationShield_Elements_03.jpg]...[Image: RadiationShield_Elements_04.jpg]

[Image: RadiationShield_Elements_05.jpg]...[Image: RadiationShield_Elements_06.jpg]...[Image: RadiationShield_Elements_07.jpg]...[Image: RadiationShield_Elements_08.jpg]

List of other hardware parts:
  • Three M4 rods with 12cm (size is for an assembling with 5 middle plates. Increase 2cm by each additional middle plate)
  • Three M4 nuts
  • Three washers suitable for M4 size

These are all the parts we need to build the Radiation Shield. On next topic we will focus on assembling.

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#3

3D Printed Radiation Shield for Meteo Stations - Part 3

Assembling the main body of the Radiation Shield

Having all the 3D printed parts at hand and the M4 rods already cut with the needed size, assembling the whole body of the Radiation Shield its an easy task, that doesn't require any special tool.

After having 3D printed all the required parts and having the M4 rods already cut with the needed size, assembling the whole body of the Radiation Shield its an easy task, which doesn't require any special tool.

Start by doing a mark on each M4 rod, at 1cm of one of the extremities. This will help you to know how much you should screw each M4 rod on the holes of the top plate. With the help of a pliers, it should not be hard to screw each M4 rod. Do it up to the 1cm mark.

[Image: RS_Assembling_01.jpg]

Before going further, decide if you want to have an aspirated Radiation Shield, or not. All WeatherDuino transmitters have a port to control the RS fan. The software allow the users to define in which conditions the fan should be turned ON. Having a fan always on, or just during the day light time, in most cases don't bring any benefits. For more info on this matter, please refer to some scientific studies (search the forum, you will find info and links to them), which clearly identified the conditions where having an aspirated Radiation Shield is important. Mainly such conditions are, high temperatures together with week winds.

Continuing with our assembling.

If you decided by having an aspirated RS, take a small 12 Volt 40mm fan (you may reuse one from an old computer hardware) place it in the underside of one of the middle plates, then do a mark corresponding to the four fixing screws of the fan. Next, using a drilling toll, do the four holes.
Before fixing the fan, verify the direction of the air flow, it should NOT be blowing the air in the direction of the sensor, but aspiring the air from inside the RS.
In the end, you should have something as shown in the picture bellow.

[Image: RS_Assembling_02.jpg]

Continuing...
If you have a plate with a fan, start by inserting it on the M4 rods. It should be the first plate counting from the top plate, then insert the next four plates. If you decided by not having a fan, insert the five plates on the M4 rods, one at a time. The holes on the plates have been designed to allow an easy insert.
After having inserted all the five plates, insert the piece which is used to later fix the sensor mounting part. Pictures below show the correct position of this part.

[Image: RS_Parts_03.jpg]...[Image: RadiationShield_07.jpg]

By last, insert the wall (or pipe) mounting piece.
If you don't want or need the optional small box under the RS, its time to put one washer in each rod and tighten the whole set using the three nuts. The assembling of the main body of the RS is finished. It should end up looking like the picture below on the right.

[Image: RS_Parts_04.jpg]...[Image: RS_Assembling_03.jpg]

On next post, we will talk about the physical and electrical installation of the sensor, and why choosing to add the optional small box below the body of the RS, can be an wise and important decision.


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#4

3D Printed Radiation Shield for Meteo Stations - Part 4

Installing the Temperature / Humidity sensor

Prior we go to the physical installation of the Temperature / Moisture sensor, let's talk a little about the sensor itself.
The most common type of T/H sensors used on DIY weather stations, no mater its brand or type, use the I2C protocol to communicate over our well know SDA / SCL lines.
The I2C (Inter-Integrated Circuit) protocol, as its name seems to indicate, was developed to interconnect devices at short distances. Often, when we want to install an outdoor T/H sensor, the distance between the best location for getting accurate readings and the microcontroller used to read the sensor, exceeds the tolerances of the I2C protocol, and we have difficulties to read our sensor, or even no readings at all. Depending on the cable used and the number of devices already existent on the I2C bus, the maximum cable length we can use to connect our T/H sensor rarely can be higher than 1 meter, which is quite limiting.
How can we surpass this limitation? There are any solutions? Yes, there are. The use of the called I2C bus extenders.

Basically an extended I2C bus is composed by two small devices, one installed near the microcontroller, the other at the end of the cable where we intend to connect our sensor. By using an I2C bus extender circuit, we can have cable lengths of 50 meters or even more.
Picture bellow illustrate the concept.

[Image: I2C_bus_extender_circuit_00.jpg]

There are on the market (ex eBay) many ready made modules which allow an easy implementation of an extended I2C bus.
WeatherDuino users are a little more lucky, as all of our transmitters, already include onboard the first part of an extended I2C bus, so users only need the second part of the circuit to place at the end of the cable, near the T/H sensor.
Here is a picture from our I2C bus extender PCB, which currently we offering with any of the WeatherDuino bundles.
(Real size is much smaller, only 30mm x 14mm)

[Image: WeatherDuino_I2C_Bus_Extender.jpg]

The reason of this preamble before starting with the physical installation of the T/H sensor on the RS, is because depending on whether you decide to use an I2C circuit or not, you will need to add the optional small box under the RS, or not.


So, lets start with the assembling of the T/H sensor.
Case you have decided by installing a fan on the RS, then you will need to add to the sensor mounting piece a small connector for connecting the power for the fan.
Pictures bellow shows the placement of the fan connector and how I have fixed the sensor to the sensor mounting piece.
Each one can find other ways, important is that the body of the sensor stay above the mounting piece.

[Image: RS_SensorMounting_00.jpg]...[Image: RS_SensorMounting_01.jpg]

If you haven't installed a fan, then, now you only need to carefully fit the sensor protection chamber into the sensor mounting piece, and insert the set inside the RS, fixing it using an M3 screw.

[Image: RadiationShield_12_small.jpg]...[Image: RadiationShield_03_small.jpg]...[Image: RS_SensorMounting_04_small.jpg]

If you have installed a fan, then start by partially insert the sensor protection chamber piece into the RS (see picture above on the right), then pass the fan power cable through the square hole near the top that piece. Plug the fan power cable into the connector. After that, carefully fit the sensor protection chamber into the sensor mounting piece, it should enter with some resistance. Now, just insert the sensor mounting piece inside the RS, and fix it using a small M3 screw (there is an hole on the base piece for that). The job is done!


Optionally, you may want to put inside of the sensor protection chamber some kind of dust filtration material. I did it.
Despite what may seem on the picture, the material used is fully waterproof while air can flow easily.

[Image: RS_SensorMounting_03_small.jpg]


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#5

3D Printed Radiation Shield for Meteo Stations - Part 5

Installing the extended I2C bus circuit.

Due to the very small size of the WeatherDuino I2C bus expander circuit (other models are small too), my first attempt was installing it on the sensor mounting piece right below the T/H sensor. This has proven being a big mistake. Don't do it.

[Image: I2C_Install_01.jpg]

Despite the circuit don't produce any detectable warm, the true is that after having installed my new RS side by side with the one I use as reference, the readings from the new one were consistently around 1.5ºC higher. This value is far from the maximum error of the sensor, so something was wrong. Initially I though the cause was the sensor protection chamber, and removed it. The high readings continued... then I removed the sensor mounting piece from inside the RS, and exposed the sensor to wind. The readings started to be very similar to my reference, with just 0.1ºC or 0.2ºC difference.
Then I realized that I would have to find another solution to place the I2C bus expander circuit, while keeping the main vantage of the RS, which is the easy removal of the sensor.
Thus was born the small box under the wall mounting piece of the RS. Now, with 2C bus expander circuit installed on the small box the readings from the new sensor are inline with my reference. I'm monitoring the logs of both for three days.

[Image: RadiationShield_10_small.jpg]...[Image: RadiationShield_Elements_07.jpg]

I think there isn't much more to say, just a few more pictures will be enough to illustrate the final construction steps of the 3D printed Radiation Shield.

[Image: RS_SensorMounting_05.jpg]

[Image: RS_SensorMounting_06.jpg]

And here is it, ready for the job!

[Image: RS_final.jpg]


STL files for 3D print this Radiation Shield are on next topic,
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#6

3D Printed Radiation Shield for Meteo Stations - Part 6

STL files for 3D print the Radiation Shield


Everything prints fine with 0.3mm resolution, without supports.
30 to 40% infill for the wall mounting piece.

Ideally, for UV protection and additional mechanical resistance, it should be printed using ASA, PETG or ABS.
I printed mine in PLA and painted all pieces (except the sensor mounting and protection chamber pieces) first with a primary for plastic, then three coats of enamel acrylic ink. Let's see how long it lasts.

This thread is now open for discussion, feel free to comment on.

To finish, I would like to apologize each of you, by had the tolerance of reading this article written in a poor English.
Thank you.


Attached Files
.zip WeatherDuino_3D_Printed_Radiation_Shield.zip Size: 837,34 KB  Downloads: 223



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#7

Heart Like Music

Best Regards
Zdenek

[Image: banner.php]
My outdoor AQM-I: here
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#8

(12-02-2021, 00:37)Werk_AG Wrote:  3D Printed Radiation Shield for Meteo Stations - Part 4

Installing the Temperature / Humidity sensor

Prior we go to the physical installation of the Temperature / Moisture sensor, let's talk a little about the sensor itself.
The most common type of T/H sensors used on DIY weather stations, no mater its brand or type, use the I2C protocol to communicate over our well know SDA / SCL lines.
The I2C (Inter-Integrated Circuit) protocol, as its name seems to indicate, was developed to interconnect devices at short distances. Often, when we want to install an outdoor T/H sensor, the distance between the best location for getting accurate readings and the microcontroller used to read the sensor, exceeds the tolerances of the I2C protocol, and we have difficulties to read our sensor, or even no readings at all. Depending on the cable used and the number of devices already existent on the I2C bus, the maximum cable length we can use to connect our T/H sensor rarely can be higher than 1 meter, which is quite limiting.
How can we surpass this limitation? There are any solutions? Yes, there are. The use of the called I2C bus extenders.

Basically an extended I2C bus is composed by two small devices, one installed near the microcontroller, the other at the end of the cable where we intend to connect our sensor. By using an I2C bus extender circuit, we can have cable lengths of 50 meters or even more.
Picture bellow illustrate the concept.
 
 

There are on the market (ex eBay) many ready made modules which allow an easy implementation of an extended I2C bus.
WeatherDuino users are a little more lucky, as all of our transmitters, already include onboard the first part of an extended I2C bus, so users only need the second part of the circuit to place at the end of the cable, near the T/H sensor.
Here is a picture from our I2C bus extender PCB, which currently we offering with any of the WeatherDuino bundles.
(Real size is much smaller, only 30mm x 14mm)



The reason of this preamble before starting with the physical installation of the T/H sensor on the RS, is because depending on whether you decide to use an I2C circuit or not, you will need to add the optional small box under the RS, or not.


So, lets start with the assembling of the T/H sensor.
Case you have decided by installing a fan on the RS, then you will need to add to the sensor mounting piece a small connector for connecting the power for the fan.
Pictures bellow shows the placement of the fan connector and how I have fixed the sensor to the sensor mounting piece.
Each one can find other ways, important is that the body of the sensor stay above the mounting piece.

[Image: RS_SensorMounting_00.jpg]...[Image: RS_SensorMounting_01.jpg]

If you haven't installed a fan, then, now you only need to carefully fit the sensor protection chamber into the sensor mounting piece, and insert the set inside the RS, fixing it using an M3 screw.

......

If you have installed a fan, then start by partially insert the sensor protection chamber piece into the RS (see picture above on the right), then pass the fan power cable through the square hole near the top that piece. Plug the fan power cable into the connector. After that, carefully fit the sensor protection chamber into the sensor mounting piece, it should enter with some resistance. Now, just insert the sensor mounting piece inside the RS, and fix it using a small M3 screw (there is an hole on the base piece for that). The job is done!


Optionally, you may want to put inside of the sensor protection chamber some kind of dust filtration material. I did it.
Despite what may seem on the picture, the material used is fully waterproof while air can flow easily.

[Image: RS_SensorMounting_03_small.jpg]


Continue on next topic...

Werk do you know what exactly the material is that you used for dust filtration? I have been having problems with dust killing my temperature sensor in my fan aspirated radiation shield and would like to build a similar protection chamber.
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#9

Hello, Werk_AG,

My translation of your posts is finished, here it is:
.pdf WeatherDuino 3D tisk RS pro meteo stanice.pdf Size: 1,47 MB  Downloads: 187

Best Regards
Zdenek

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My outdoor AQM-I: here
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#10

(11-03-2021, 00:19)hornychz Wrote:  Hello, Werk_AG,

My translation of your posts is finished, here it is:

Dear Zdenek,

Do you believe that I don't even have a PDF or Word document of the original post?
Well, now I have one!!! Like
Thank you very much, it looks really good and I'm sure it is very well written. This should have took a lot of your time to do. Thanks again.

Rgs.
Werk_AG
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