Topic: Barani pro passive shield

[ivano]

hi, after many tests with my meteshield pro and sht35 EP sensor, the optimal position for the sht35 probe is this

Thanks for that! What kind of material did you use to extend the length of the probe body?

i used a piece of a carbon fishing rod, but you can use a pvc pipe the diameter of the sensor base

[Julius]

My assumption is that adding the SHT35 probe (https://nl.aliexpress.com/item/4001220756351.html?spm=a2g0s.9042311.0.0.70234c4dEBTHiQ) will see the same results in a second Barani shield I added.

Did you add this sensor directly to your Davis VP2 base? Interesting ali link you've posted there.

[hmderek]

My assumption is that adding the SHT35 probe (https://nl.aliexpress.com/item/4001220756351.html?spm=a2g0s.9042311.0.0.70234c4dEBTHiQ) will see the same results in a second Barani shield I added.

Did you add this sensor directly to your Davis VP2 base? Interesting ali link you've posted there.

No the sensor is connected to custom setup with a Wemos microcontroller. (Inside the box next to the left of the Davis Rain collector)

[hmderek]

This should work.

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[vsakalis]

Hello to everyone

During my 2 yeas of scientific researtch in passive radiation shields,  I want to put into conversation some desigh parameters which I thing they are very interesting:
1. The time constant of the temperature devices which is very important and differs when several coatings of the sensor are used
2. The performance of the radiation shield/temperature sensor under low wind speed (less than 1 m/sec)
3. The position of the sensor inside the shield
4. The material of the shield (ABS plastic, PVC, HDPE...), affects the performance especially during the night when long wave radiation is important

Generally speaking, as a results from my experience, the test periode of the radiation shields performance must be more than 1 month and at least with 5 min time intervals. This month couldnot be the only June or December, preferable the period between May and September.
Mean temperature error, mean absolute  error and root mean square error during this period must be calculated in order to check the performance. In addition, the difference between max, min and average temperature could be one more option. All these parameters need a more accurate reference temperature device, which must be of course arificially ventilated.
And something more...dont forged the need of calibration of the devices owing to the drift of the sensor!

[galfert]

My assumption is that adding the SHT35 probe (https://nl.aliexpress.com/item/4001220756351.html?spm=a2g0s.9042311.0.0.70234c4dEBTHiQ) will see the same results in a second Barani shield I added.

Did you add this sensor directly to your Davis VP2 base? Interesting ali link you've posted there.

It would be nearly impossible to add the SHT35 to the VP2 because the SHT35 only comes with I2C bus protocol version and the VP2 does not support this. The VP2 uses the SHT31 because it is available in LSS (Lagacy Sensiron Sensibus) version. The SHT31 also comes in I2C version. Therefore the VP2 is limited to no better than the SHT31.

[hmderek]

Well it definitely looks like adjusting the placement of the sensor has had desired effect. Of course I'll have to wait until summer to see how it really fares, but the jumps in temp under solar radiation spikes are gone for the SHT35.

[Marty]

This should work.

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Is that 1/2 " pvc  pipe  ...

   Just installed my Meteoshield Pro with Ecowitt 32wh-ep sensor   and i have to say comparing this to a converted and painted inside flat black vp2 24h  newer year old sht 31 sensor    is   that right of the bat 10%  Humidity difference  at peak but overall all day is around 7%..
 As far as Temp very quick response with  Pro shield compared to Davis but as 40 Latitude there is very littles sun now.  High temp .5F lower on pro  but was the    same for low   for 1 day comparison ...

Just checked Barani web site and sensor placement is 7.5cm  +-2.5cm  so around 3+ inches from base

[CW2274]

This should work.

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comparing this to a converted and painted inside flat black vp2 24h 

This is not meant as a criticism, my VP2 has modifications as well, but the 24hr VP2 shield is patented. The sensor chamber has the large, black disc at the bottom for this purpose. Do you feel your mod is necessary/beneficial over stock?

[Marty]

This should work.

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comparing this to a converted and painted inside flat black vp2 24h 

This is not meant as a criticism, my VP2 has modifications as well, but the 24hr VP2 shield is patented. The sensor chamber has the large, black disc at the bottom for this purpose. Do you feel your mod is necessary/beneficial over stock?

No worries ,   My vp2 is total Frankenstein  started as standard vp2 then added daytime fars and ended up with 24h conversion ...

and its for sale ,   best offer 

20201224_112231 by Marcin Madry, on Flickr

[Jorginho]

So we have had a lot of snow (for our standards, about 15-30 cm of snow fell in most parts of the country) and since yesterday it has been very sunny and bright. Now today in the centre and north of our country we see KNMi stations shooting up in temp. From -9 C to 0 C in a matter of an hour. First people thought it was an error, but soon others followed. All above zero. Not in my regio. One reason: no wind. No wind meant -15 to localy -21 C. But it also means plus degrees. So we have Hupsel at +1.7 C and Twenthe, just 20 miles NE under the very same local conditions but with a little wind at -2,8 C.

What have we witnessed: KNMI removing at least some of the exceptional values. I checked it and the KNMI has three screens operating at the Bilt and all showed  a similar rise with the 0,0 C value sitting right in between. My suspiscion: they have corrected here due to radiation errors.

Now interestingly at Silvolde we have a Davis that registered -2,8 C and a Barani at the same field that registered -3,8 C. Silvolde is close to Hupsel. It has a little wind (1 m/s). But it seems we seen the problems with radiation errors now: very clear sky, no wind and lots of snow...

I also noted a KNMI station at De Bilt named KNMI LoRa...It is not in use currently, but what could that be? May be...?

[jerryg]

I haven't post on here in some time but i decided to try testing how the height of the sensor placement in the shield might make a difference in performance of the Pro shield. I am comparing it to my Young 43502 shield. Both sensors are the sht 31 and have been calibrated to match each other and the shields are co-located on my weather tower at the same height. First results with wind blowing all night both shields read the same low temp of 56.3 and with the sunshine this morning and still good wind blowing the Pro  has been running about .4F lower than the Young. Now i need a calm wind day with sunshine to see how The Pro with the repositioned sensor holds up against the Young. I have high solar here in South Texas at a lat. of 27.8 degrees and no snow problems so readings are over grass.

[jerryg]

A quick update, winds were blowing today and mostly sunny with some clouds in the afternoon and surprisingly the Pro was running 1.3 degrees lower than the Young shield and when a cloud moved over the Young temp dropped down to the Pro temp and went back up with the return of the sun. Now which is right, so i put my Davis 24 hour shield back out and calibrated to match the other two. It is supposed to be sunny tomorrow and i will get to see if the Young is reading high compared to the Pro and the Davis shields.

[ashland weather]

It is good to see you back.  I have been thinking about getting the Barani shield.